Gamo’s Urban precharged air rifle: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2

Gamo Urban
Gamo Urban.

This report covers:

  • Scoped
  • The test
  • Sight-in
  • JSB Exact Jumbo
  • Air Arms Diabolo Field
  • H&N Baracuda Match
  • Other pellets
  • Experience
  • What next?
  • Summary

Today we start our look at the accuracy of Gamo’s Urban PCP. Fasten your seatbelts, guys, because today will be a bumpy ride!

Scoped

I mounted a 4-16X50 Leapers scope that is obsolete, and is unlike any scope they make today. But 4-16 power is the key.

Knowing the Urban’s performance curve, I filled to 3000 psi and shot 20 shots before refilling. There are 25 available at this pressure, but I was shooting 10-shot groups, so 20 was the limit.

The test

I shot the Urban off a sandbag rest with the rear of the butt rested for extra stability. The range was 25 yards.

Sight-in

The first shot hit the target from 12 feet about 1.5 inches below the aim point, and centered on the target, so I moved back to 25 yards and resumed sight-in. In 5 shots the rifle was zeroed, and I sighted the first pellet a little high to preserve my aim point.

JSB Exact Jumbo

First up were 10 JSB Exact Jumbo pellets. I thought they might be great in this rifle. But the shots seemed to scatter, despite all that I tried to do to hold the rifle steady. In the end there were 10 pellets in a group measuring 0.683-inches between centers. That would be good for 50 yards, but not so great for 25 yards.

Gamo Urban JSB group
The first group of JSB Exact Jumbos was okay but not great. It measures 0.683 between centers for 10 shots at 25 yards.

Air Arms Diabolo Field

Next I tried 10 Air Arms Diabolo Field pellets, thinking they would be the ones to make this Urban shine. Ten went into 0.623-inches at 25 yards which is a little better, but not much. What was going on?

Gamo Urban AA group
The second group was 10 Air Arms Field Diabolo pellets that was better, but not by much. It measures 0.623 between centers for 10 shots at 25 yards.

I would like to point out that I shot out the aim point this time. In fact, the first shot was a pinwheel that took out the 10- and 9-rings. I’m just saying that I managed to better without a precise place to aim.

H&N Baracuda Match

Maybe the Urban wants a heavier pellet? So H&N Baracuda Match pellets with 5.51mm heads were next. They hit the target almost 1.25 inches below the aim point and nearly the same distance to the left. They hit so close to the edge of the paper that I left the target taped to the cardboard backer for photography.

I really hoped this pellet would be the one I was looking for but the group measures 1.479-inches between centers, so I guess not. Also, this was the first group with significant fliers. What was happening?

Gamo Urban Baracuda group
Ten H&N Baracuda Match pelletsmade this 1.479-inch group at 25 yards.

Other pellets

I had only planned on shooting three pellets in this test, but the best-laid plans of mice and men gang aft agley! So I looked around for others to try. The first that came to mind were Gamo Hunter pellets. I’ve never done well with these, but the Urban is a Gamo rifle, so if they are going to shine, this would be the place.

They were horrible! One missed the target trap altogether and I stopped shooting after 4 rounds. I was about to give you a lecture on non-premium pellets, but first I thought I’d try the old standby — Crosman Premiers. And, when they shot no better than the Gamo Hunters, I knew there was a problem. This Urban I’m testing isn’t working right.

Gamo Urban scattered pellets
Three holes are Gamo Hunters and the rest are Crosman Premiers. When Premiers do this, something is wrong. Notice than several of the pellets wanted to go to the same place.

Experience

This is where experience pays off. The Premiers grouped tight when they weren’t scattering. This was not a pellet issue — it was the gun!

My experience is whenever pellets start scattering this way out of a silenced gun, they are touching something on their way out — especially the last baffle. Sure enough, when I looked I could see where they had been hitting the baffle.

Gamo Urban baffles

What next?

I do not plan on taking this Urban out to 50 yards the way it is now. I probably couldn’t keep them all on the paper at that distance. This has to be corrected before anything else happens.

If this were my rifle I would drill out the last baffle, going through the muzzle. You have to go through the muzzle because the silencer seems to be permanently attached to the barrel. The end cap is pinned on and that might give better access to the baffles, but I think the silencer remains on the gun.

It’s all moot, though, because I don’t own the rifle. So I can’t modify it in any way. I will ask Pyramyd Air what I should do.

Summary

I hope this isn’t the end of the Urban test because I think it’s a very nice air rifle. This one just has a problem. I don’t think it’s something that’s common because I have heard a lot of good things about this rifle.

156 thoughts on “Gamo’s Urban precharged air rifle: Part 3

  1. Kudos for correctly quoting Rabbie Burns.

    I am betting you get permission to drill the suppressor. It would be shocking if Gamo wanted to leave your review as it is, and Pyramid couldn’t sell the rifle in this condition even as a discounted, “demonstration model.”

    I hope you tell us who is footing the bill on the write-down when you retest this after drilling it, I am 60/40 on Gamo marketing department.


    • But what about all the other Urban’s? Does Pyramyd Air get a flood of returns?

      And now do people take a chance on getting a good one or a bad one. Yep opening up the silencee and removing the baffles is a option as stated below. But what about the people that are buying it because they want a silenced gun.

      I never been crazy about the Gamo silencer design in the first place on their other guns. And of course they would carry it over to this gun.

      I do like the Urban. But to bad they didn’t put a shroud on it like other manufacturers are using. I think I could say I would of tryed one if they did. Or even left it off completely for that fact.


  2. B.B.

    Wow! That’s too bad about the baffles. I wonder if the baffle could be moved a little so it didn’t interfere with the pellet. I have only been able to get outside to shoot my Urban once because of the cold and snow here in MI. I did manage to shoot a few shots at 25 and 30 yards and the groups were less than 1/2″. Most of my shooting has been down in my basement at 17 yards. I get hole in hole at that distance with JSB Jumbo Heavies 18.13g. I had a few JSB 15.89s and they appeared to do well too. I need to test those out at longer ranges. The CPHPs didn’t do well even at 17 yards, nor did Superdomes.

    I sure hope you can resolve this issue and continue the test. I was so looking forward to it. Darn 🙁

    Geo


    • Geo,

      I finally finished gathering the data on the hammer spring preload for both of my Urbans. You will be able to tell by the charts and graphs that Gun1 is broken in and Gun2 still has a ways to go. I’d say I had about 750 more shots on Gun1 when I started this. I did both guns so that you guys that will be using the info would have an average to work with, but now I think I would characterize it more as a before and after break in study.

      I elected to do two turns of adjustment at a time because of the number of shots involved. I think that you will be close enough if you just halve the distance between two adjustments’ results. It still ended up being well over 2500 shots anyway because the three gauges involved don’t agree with each other. I was not consistent in which gauge I was referring to at different stages of the test so I had to throw out all of the first data set and do it all over– live and learn. The upside is that Gun2 got more break in before I collected usable data. I also chose to use the cheapest pellets that I had, which as we all know, is Crosman Premier Hollow Points. And that was also because of the number of shots involved.

      Rather than list every shot in my charts, I chose to list the average of each 10 shot group and I recorded, on paper, the other statistics for each 10 shot string, but didn’t include them in my charts. I can say that the SD,MAD,and ES for Gun1 was much tighter, usually, than for Gun2 in pretty much all instances.

      I was as careful with my method as I know how to be after having to throw out my first data set. My SCBA tank’s gauge readings match my hand pump’s gauge so I chose to trust the tank gauge. Gun1’s gauge reads 100 PSI high and Gun2’s reads 300 PSI high. The gun’s gauges are tiny little things and they are only graduated every 1000 PSI, which isn’t fine enough, so I used an app on my smart phone, Geo. Let me repeat that, an app on my smart phone 😉 that allowed me to capture an image of the gauge face that was 3 3/4″ in diameter. I could read it confidently to the nearest 50 PSI. I would then subtract 100 PSI when I was testing Gun1 and 300 PSI from Gun2’s readings. I recorded that adjusted number and it should be what you would fill your gun to using an accurate gauge. I had to do this at the beginning of every string but it was what was required to gather meaningful pressure data.

      When I got to the 14 and 16 turns part of the test, I chose to record the entire string since it only required 30 -35 shots and if anyone wanted to hunt using the highest available power from one of these guns, I thought it would be more useful than a couple of 10 shot averages would be. I also put those strings into their own charts.

      This is Gun1 from 0 turns to 12 turns. The lower set of numbers is the starting pressure of each string. In each column, the last number is usually the pressure that was left when I finished the test at a given number of turns. I stopped recording data when a string returned an Extreme Spread of 50 or more. The velocity numbers in the middle of each test will usually have the tighter statistics within each string of 10 and they increase as you move out from there.


      • Thank you for all your efforts. I don’t quite understand your charts. Let’s take Urban one at 8 turns for example. It looks like the average velocity for the first 10 shot group was 751. What was the number of shots per fill? What was the fps spread per fill? Thanks


        • I think I got it now. The number of shots per fill was 60 at 8 turns. As you said you stopped when the spread got greater than 50. You started at 3300 PSI and ended at 900 PSI. Did I get it right?


          • Johncpen,

            That’s it exactly. It’s 60 shots but I have to leave it to you to decide how many of them are ” useful “. The last string would have a spread of at least 50 fps or I would have kept going, so that average is a little shaky, if you know what I mean. Listing every shot would have been too much of a job so I used averages.

            I, for instance, might conclude that on Gun1 at 8 turns I could fill to 2650 and shoot down to 2000 and I would get about 30 of the most stable shots I’m gonna’ get at 8 turns and that they will average around 810 fps. Your mileage may vary, as the saying goes.

            Half


        • Johncpen,

          You’re quite welcome. Just let me know if it was helpful if you end up using it somehow, and by all means ,DO use it if you can. That’s is what will make the effort worthwhile to me.

          Half


          • I haven’t adjusted anything yet. I’m still at factory settings. I pump it up to 2500 and get 20 or 25 shots before I pump it up again. I use it to plink but I like to be able to hit at 60 yards or so. Once I figure out how it does at lower power, I will enjoy getting more shots per fill. To begin I want to turn the screw counterclockwise all the way out and then turn it in clockwise counting the number of turns, correct?


            • Johncpen,

              That’s correct. I went by what I could remember from the “lost comments” from Part 2 of the Urban report. If you go more than 16 1/2 turns CLOCKWISE the adjuster unthreads and just spins with no additional adjustment. On one of my guns this also resulted in not being able to cock the gun because the spring became coil bound. So to get a starting point you have to turn it all the way COUNTER-CLOCKWISE (Anti-clockwise, to our British friends) until it stops. I tested it and it is repeatable.

              Half



                • Johncpen,

                  I did all of this with Crosman Premier Hollow Points ( CPHP ), which I think look just like the Ultra Mags with a tiny dent in the nose. I shot over 2500 of them but I actually shot them from nearly a dozen tins. It was at 12 yards and the guns were out of their stocks and clamped in a portable vise-like tool called a Jaw Horse ( you can Google it) that I have weighted down with some sandbags and lead bags. I watched every shot go down range and found that pellets from some tins would group great, which I defined as 10 shots in a group around the size of a pencil eraser at this distance, at 600 or 700 fps and then fall apart as the velocity increased. Pellets from other tins shot like crap at lower velocities and only shined (shone ?) at the max velocity that the gun would produce (900ish fps). Pellets that shot well in one gun didn’t always in the other. Sometimes it was rainbows and unicorns in both guns. I would see 3 or 4 shots go into a .22 hole without enlarging it and the next 2 would hit 1/4″ high then 1/4″ low. All of that was secondary to what I was trying to accomplish so I don’t have a ton of notes, but I did try to note on the tin what gun and velocity it seemed to like. For my own purposes, I may explore this more. I also had a couple of tins that weren’t much good in either gun at any velocity and they were the ones that I did most of the shooting with ’cause they were junk, right?

                  If what I saw with the CPHPs carries over to the Ultra Mags, then you may find that your next tin doesn’t shoot well or has to be fired at a lower velocity to get the results that you are getting now. Most of these pellets were bought at the same time, for what that’s worth and I just received 10 tins of Ultra Mags today, all from the same place. I will probably do some tin to tin compares with them as well, at some point. I’m dying to figure out why some folks rave about how well Crosman pellets shoot in their guns and others think they are a waste of lead that could have better used to poison our environment. ( What , me bitter?)

                  Half


                  • Halfstep,

                    I would not hold my breath on Crosman pellets being very consistent from tin to tin,.. or even within the same tin. They are cheaper for a reason. Extensive PelletGage testing would be needed to confirm. You may look back at B.B.’s PelletGage reports to see if any data exist there.

                    I would bet that data already exist from people who have already done extensive head and weight sorting on the Crosmans.


                    • Chris U,

                      The thing I find intriguing is the tins that seemed to shoot well at one velocity and not others from the same gun. I’d kind of like to get a handle on the differences between the pellets that may be causing it. That will be down the road though.

                      Half


                  • In my limited experience I find my Benjamin Maximus shoots the hollow points just as well as the domes. I started reducing my power today in the urban. I was a little concerned that it took a lot of effort to start screwing counterclockwise but then it got easier. Currently, I am at four turns and with a little bit more hold over I’m still hitting accurately at 40 and 50 yards. I only filled to 2000 PSI and have shot 30 rounds. I’m going to go for 10 more and see if the power drops. This experiment is helping me to decide between this gun and the Benjamin Maximus. I am leaning towards keeping the Urban and returning the Maximus. The trigger being stock on the Maximus is a big negative. I haven’t done anything to reduce the pull of the trigger, but I prefer the pistol grip much better in the urban anyway. With the longer screw in the urban I think the trigger is terrific. I got a good deal on the urban for $228. Thanks to BB’s timely review, I found a good deal, and will probably be happier with the Urban.


                    • Johncpen,

                      One of my screws was stiff for the first few turns but the other one was easy from the git go.

                      Is the setting that you are using better for your needs than the factory one, that’s assuming you can get 10 more shots, I suppose ?

                      When making an adjustment with a threaded adjuster it is always best to keep the backlash out of the threads. For instance if you decide that you only want 3 turns after this, I wouldn’t advise just backing off 1 turn. I think you will get a more repeatable result if you start from 0 and go forward 3. May not matter here but in general it will serve you better.

                      Anywhere in that price range and this gun is a steal as far as I’m concerned, especially now that I know that it has a hammer adjustment. I wish I could remember who posted that so I could thank him. I really do feel like I just got 2 new guns.

                      Did you leave the end cap off when you restocked your gun? It looks like it will give access to the adjuster without taking it out of the stock while you are trying out different settings. I think I’m going to give it a try.

                      Half


                    • John
                      So now that you reduced power and I guess shot group’s. Can you tell what your usable shot count is? And that’s with no chrony right?



                  • I only filled to 2000 PSI and seems like I got 40 good shots before the power dropped off and the gun started sounding differently. Yes the groups opened up but I was still able to plink easily. I have no chrono.


                    • John
                      That’s how I use to do it before I got a chrony.

                      Well still do even now that I have a chrony. The only time I really use my chrony is if I made a power change.


      • Halfstep,

        You sure did a lot of research obtaining all this data. I am a little confused as to the number of turns. What was the original setting before you made you adjustments to the hammer spring. Did you back the screw out completely for “0” and then start from that point turning the screw to increase the pressure. I’m kind of lost with the chart with no point of reference.


        • Geo,

          As I explained to Johncpen, I had to go with what I could remember from that post in Part 2 about the Urban. That person revealed then ( I really wish we could recover those comments so I could acknowledge the poster) that the Urban had an adjustment of 16 and some odd number of turns. I think it was 16 1/2. He said, at that time, that you had to begin from a completely bottomed out, counter- clockwise start because if you go clockwise you will eventually unthread the adjuster completely and it will just spin without making any further adjustment. So for both guns, 0 turns means all the way COUNTER- clockwise.Then I turned the adjuster in 2 turns to begin each of the subsequent tests. So I guess the short answer is, yes, I started with the screw backed all the way out.

          It isn’t a factor in the test results, but for informative purposes, Gun1 was set at 10 1/4 turn and Gun2 was set at 10 3/4 turns from the factory, again, clockwise after being turned all the way counter-clockwise as a starting point.

          Half



          • I found in another forum that the way you did it is exactly the way they did it for the same reasons. Mine was set at 13 and a half turns from the factory by the way.


            • John,

              As for why it started hard and got easier,…. it is not uncommon to have bolts with a strip of thread locker built in/applied to the threads. The striker adjustment on the M-rod had that. I also found that the striker adjustment would (migrate) and required some blue Loctite to keep it in position. So yea,… while we are talking about screwing things in and out,… it pays to keep in mind that the adjustments may move on you during shooting. I know for a fact that they did on the M-rod.

              The Maximus trigger can be set up real nice with minimal work,… but I think that I may have mentioned that before.


              • As I was unscrewing it, I was hoping it was tight due to threadlocker. Thanks for your comments. I’ve done some research on how to improve the Maximus trigger, but if I like the Urban Better (which I am leaning towards), then I’m going to return it anyways.



                  • With my limited testing I’d say the urban is a little more accurate, but it depends on your power setting. Maybe the Maximus would be as good or better with a lighter trigger.


                    • John
                      My Maximus is very accurate. Even when. I had the factory trigger.

                      Yep it’s always nice to have a “better” trigger. But usually I can adjust my trigger pull to whatever gun I’m shooting.

                      And maybe more like it’s pellet choice to me that would make the gun more accurate.


              • Chris USA

                I was curious about whether or not that would happen with my Urban while I was testing, so I left the Allen wrench in with the short arm sticking out on the left or right side of the gun ( 9 o’clock and 3 o’clock ) I figured gravity would encourage it to move if it was going to. For what it’s worth, it never did. If I go inside for any reason I will use the Loktite as you recommend, though.

                Half


                • Halfstep,

                  That is good. The striker adjustment on the M-rod is inside the hammer. A hammer within a hammer if you will. At any rate,… it is something that is good to keep in mind. (Good) idea on leaving the allan wrench in. That is real time testing with 100% visual conformation. 🙂


                • Halfstep
                  From what I gather the Urban only has the striker spring adjustment.

                  The Marauder has two adjustments that can reached at the back of the air tube. And without having to take the stock off.

                  But as Chris said the striker stroke adjusting screw can turn as you shoot. Not so much the striker spring pressure adjusting screw.

                  What I found to do on the Marauders is back the stroke adjustment screw all the way back for full stroke. That way you can lock it in tight and not worry about that. Also that helps to prevent the striker from resting on the valve stem and causing a slow leak from the valve.

                  I believe the wound ends of the spring keep the spring pressure adjustment from moving.


            • Johncpen,

              Wow, that’s higher than either of mine by a good margin. I wish you had a chrony so you could tell me how fast it was shooting like that. LOL I wonder if Geo791 has turned his out to see what it was set at?

              Half.


              • Halfstep,

                No, I have not touched the screw on my Urban. Really, I see no need to adjust it from where it was set at the factory. I would add that the hammer springs may not all have the exact same length, or force at a set length. I used to measure the rate on coil springs used in our hydraulic pumps at work. There is a tolerance but as long as they fall within the engineering specifications they are good. But there is some variance from spring to spring.


              • All I can say is that it penetrated more than my Benjamin Maximus. I shot at 40 yards with four turns and so far it seems like my groups opened up quite a bit, but I can still hit cans most of the time. I got 40 good shots only pumping to 2000 PSI. I’ll have to try leaving the end cap off. Thanks


              • Halfstep
                I mentioned this before. Kind of like the spring guns I have had. I cut upto 4 inches of the spring and the gun still shot the same velocity.

                What I think is happening on the Urban is the spring is doing nothing for velocity after a certain preload is met.


              • I haven’t done too much shooting on paper but I just wanted to let you know that at 4 turns and 40 yards my target of a small prescription pill bottle is getting hit 9 out of 10 times from a rest. Considering I get 40 shots from 2000 PSI, I’d say your information was very beneficial to me.


                • Johncpen,

                  That’s great! I’m really glad it helped. I benefited too. Look at my comment to Idaho on Part 4. It’s near the end of the comments at around 8:57pm. I turned my adjuster in to 15 to get those results. ( I have a compressor so I can go big time. Only get 22 good shot though.)





      • Halfstep,

        Thank you for that extensive testing. Superb data/graphs as always! 🙂 I appreciate the hard work, time and expense incurred.

        So,.. we now know that not only the hammer preload can be adjusted on the Urban, but we also now have very good data from not just one gun,.. but from two guns!

        I think most people will not have a chrony and also think that most owners will be shooting the cheaper Crosmans. Your data also enables a person to use Chairgun with a fair bit of confidence on fps input.

        Again, fine job! I would have commented sooner, but yesterday the laptop was running super slow and acting really stupid. It may have been the incoming speed at the time? and I just shut it down around 3pm. It is all good this AM.


        • ChrisU,

          It must have been something in the air. At one point yesterday I was runnin’ super slow and acting really stupid, too.

          You’re welcome and thanks for the accolades. I had really hoped for a better average between the two guns but Gun2 is just not as broken in yet. It doesn’t show in the charts and graphs, but within each of the 10 shot strings on Gun2 the SD and ES were pretty high. Gun2 , on the other hand, had some impressive numbers, I think at least, for an unregulated gun. Would you think that hammer roughness or need for lube on the hammer could be what is causing the spiky graphs for Gun2? I also wondered if introducing a little silicone oil into the air stream to lube the valve would help.

          Half


          • Halfstep,

            The oil can’t hurt. As for the hammer,… I do believe that when I was playing around with the M-rod,.. bone dry was the preferred method. I do believe that others have reported bone dry ~ to all gunked up when tearing into them. Burrs could be an issue, but you won’t know until/if you tear into it. If you think it is still breaking in, then I would ride it out awhile longer.

            As for pellets,.. there is as many variables as the day is long. It could be that all pellets have a (magical optimal speed)? Collecting hard data from something like PelletGage and weighing would be my first plan of attack. Eliminate and control that,.. and you are left with pellet fit, fps and shot curve characteristics. So many pellets are so close in appearance that it would take something pretty scientific to determine which design has what effect and limits.

            Lets say a pellet likes to be launched at 850, but you are doing them at 950. Does the ballistics suddenly get better when it slows to 850? They all slow down right after leaving the barrel,.. so what matter is launch speed anyways? I don’t know. Just thinking out loud. 😉

            All that is nice to know,… but for me, today, it is just a tin of JSB’s. I have done it though.


            • Chris USA,

              From the same barrel, a different velocity would impart a faster or slower spin rate on the pellet as it travels down the barrel and even the diabolo shape relies on that, after a certain distance down range, for stability. I was also thinking that too fast could possibly rip the pellet out of the lands and prevent it from spinning or even worse distort its shape so much that it wasn’t as aerodynamic as it started out. And I think you are right on what a complete study would entail. Maybe a project for next winter. 🙂

              Half


              • Halfstep,

                Yup,.. you can’t spend all of your time researching ehh? 😉 I suppose the goal is good ballistic coefficient (BC). We all know that Diablos are not known for that.

                Sometimes I think,.. and pretty well know,… that I almost enjoy solving problems, testing and crunching data more than I do shooting. The “thrill of the hunt” so to speak,… The hunt for the “ultimate” answer. I have also learned that it can be slippery slope down the proverbial rabbit hole and a never ending slide.

                I would imagine after this recent test that you have done,… that you may feel like you have been on a week long big game hunt, climbing up and down the Rocky’s, in pursuit of big horn sheep,.. or something? 😉 Exhausted.

                I know that when I have been on a “mission”,.. I find it to be nearly all consuming.



                  • Halfstep,

                    “Scientific (ballistic) research” at any rate ehh? 😉 I know only because I have been there. I must say though,… your efforts and data representation have far exceeded mine. Keep it comin’ whenever the mood strikes ya’.

                    My biggest downfall,.. if you can call it that,… is cooking. I find that I do so much that I am worn out and not in the mood to shoot. I must find a balance,… as I enjoy both.
                    Then again,… maybe pellets with a balsamic reduction sauce???? Naw,… that sounds like a pretty bad idea come to think of it! 😉



    • Geo,

      I hope you and anyone else that has an Urban and no chronograph can at least get some notion of what power you’re getting at a given hammer preload. Let me know how you use it or if there is any way that I could present the info that would be easier to use, since that’s mainly why I did it.

      Half


      • Halfstep
        Man gun2 is definitely not consistent compared to gun1. I wish you would of shot group’s at like 25 yards or something to see what each gun did on paper.

        The guns were definitely more consistent at the lower spring pressures.

        That brings up the next point of tuning a PCP. The transfer port diameter size. I know your showing people facts about how your Urban’s are performing. But that’s the thing about a Marauder. You have the option to make the transfer port flow change. That also helps get the gun more consistent. As it goes less is more. You can get a much more consistent gun if you decrease transfer port flow. Plus helps you tune velocity for a given pellet.

        Nobody that I know of yet that knows anything about PCP tuning says it’s easy. I mean you can get good results. But to get the best results you need that transfer port adjustment.



        • GF1′

          When the weather around here improves my next move will be to shoot Gun2 at 30 and 50 yards with a large number of pellets. I will set the gun back to the original factory setting of 10 3/4 turns when I do. For the record, Gun 1 was set at 10 1/4 turns from the factory. Hang in there ,I want to know the same things that you do about these guns.

          Half


        • GF1,

          I can’t remember who it was at the moment, but before I read their post here, I didn’t know, and I’m not sure anyone else did either, that there was ANY kind of power adjustment to work with on a Gamo Urban. Just one more thing to confirm for me what a value it is. I feel like I just got two new guns, frankly, and couldn’t be more tickled about it.

          Half


          • Halfstep
            I remember that. And now that you found out. Does it make it help you tune it.

            I’m just glad that you are seeing how difficult it can be to tune a PCP. Or not.

            If you would back up your graphs and such with actual paper groups it might just make things easier.

            I hope it don’t discourage people from getting a PCP by all your data and such. It’s not really that hard.

            Shoot some group’s from a beginning fill to a end fill and you will see what your gun can do.


            • GF1,

              It sounds like you might be intimating that I wasted my time to some extent with this project. I hope that’s not the case because I put a lot of effort into it and to my mind, at least, it could have some value to people who don’t have chronographs.

              I don’t think anything that I have reported with this would remotely discourage anyone from getting a PCP or tuning their gun after they get it. Quite the opposite, I think it is giving them a place to start and showing them what to expect from different adjustments of the hammer preload spring. Of course they will have to shoot different pellets to hone the accuracy, but there really isn’t any point in searching for an accurate pellet at 4 turns on the adjuster if the aim is to use the gun to kill a ground hog at 40 yards. There won’t be enough power. If an owner wanted to get more shots at a lower pressure because they have to pump by hand, as reader Johncpen expressly told me when I asked him, I think this information will help.

              I had a particular goal in mind when I undertook this; to provide some sort of reference for the folks that owned this gun and wanted to change the hammer preload, for whatever reason, and would have no idea what velocity they were shooting at because they couldn’t chrony it. I can’t fathom how adding “actual paper groups” would have moved me closer to that goal. If you, on the other hand, want to chronicle the need to “shoot some groups from a beginning fill to a (sic) end fill” let me be the first to encourage you to devise a test and put up the results. All information is good.

              Half



                • GF1,

                  “Shoot some group’s with the info you gave and I might get interested.”
                  I don’t understand so I wouldn’t know where to begin.

                  “What happens on paper is what counts.”
                  That seems like a rather narrow view that may not be shared by the folks that I did this for.

                  Half


                  • Halfstep

                    Show me groups.

                    Again. I Want To See Results On Paper.

                    That means I want to see the group’s the gun gets at that setting.

                    Nothing else but that.

                    Is that hard to do for you or hard to understand?

                    GROUPS ON PAPER.

                    That IS what matters. That’s all I’m asking for if you give your data. Then it will be more realistic.

                    I’m Done.


              • Halfstep,

                Thank you for putting forth all the effort to do this research for us Urban owners. I will have to study your graphs more to understand better what the data shows.

                Based on your research, do you feel that the factory optimized the setting as a compromise of power and number of shots per fill? From studying the graphs, I don’t see how an adjust would improve the Urban’s performance. I did see where you said the original hammer spring setting was 10 1/4 turns on Gun1. How did you determine that?

                I have found your research to be interesting but not sure how to apply it to make the Urban perform better than it already does.


                • Geo,

                  Can you see how it would enable a person to fill at a lower pressure and still get more shots if he wanted to just use it for plinking candy suckers at 25 yards? If you look at Gun2’s chart for 0 turns you should see that you can fill to 2100 (easy with a hand pump) and shoot down to 1050 and get 70 shots that will be powerful enough for feral cans before needing a refill.

                  If you look at the 16 turn chart for Gun1, you can tell that if you fill to 2850 and shoot down to 2050 you’ll get about 21 shots between 885 and 900 fps. I think most hunters would be thrilled with that tight range at that power level and you can’t get it with the factory setting of 10 1/2 turns, and without a chronograph or this kind of information I don’t know how you would get there.

                  I asked if there would be an interest in this info and you said you would be interested in anything I could produce. I assumed you had a use for it. I hoped there would be several.

                  Half


                  • Halfstep,

                    Yes, I am very much interested in any information regarding the Urban that you would like to share. I do appreciate all the work you have done to show what various hammer spring tensions have on fps and shot counts. I do see what you mean about more shot count, or more power, with the settings.

                    There is nothing in the Urban’s manual indicating the adjustability of the hammer spring tension. Would changing this setting void the five year warranty? If so, this would not be a good thing to do with a new rifle.


                    • Geo,

                      Since the manual is so generic and doesn’t address the adjustment in any way, specifically, I tend to think it would be allowed. All it requires is unstocking the gun and my two guns each had different settings so I don’t know how they would ever detect that they were adjusted by the owner.

                      Half


  3. B.B.,

    The only thing I could think of is to basically shoot it until the baffle problem is resolved. That, however, will take an inordinate amount of pellets.

    Siraniko


  4. B.B.

    What would you do if it was your rifle?
    I would think about sawing off the last 1/2 inch off of the entire LDC housing. Making the barrel one baffle shorter. It looks like the are still 2 others. Then I would take a round piece of plastic and drill a 1/4″ hole in the center and glue in a new endcap. Assuming I like the rest of the gun and did not have the warranty to rely on.

    -Yogi


    • Yogi,

      The baffles are molded as two halves of a clam shell. With the pins removed from the end of the suppressor the cap will come off and the two halves of the baffle assembly can be removed. It will be loud but the pellet won’t hit the baffle as the test goes forward. We would even get a before and after review on the effectiveness of the suppressor.

      The hole is so much bigger than the pellet it might respond to a little heat from a hair dryer and a nudge over towards the point of contact.

      Hope it doesn’t end the review here.

      Half



        • Yogi
          Probably so on the alignment.

          On some guns I had. And notice I say “had”. The pellet would clip the baffle once and then start getting bad groups. Then if you continued shooting kind of like Siraniko said. You would shoot that flared out spot off. But it would be so close to hitting and then finally clip it again.

          Baffle clipping can be tricky. But once you see it happen you might as well just stop as BB said and figure out where to go next.

          That’s the thing about the baffles. The tolerance of the hole in the baffles has to be pretty close to the diameter of the pellet for it to effectively silence the shot. Well guess what happens next if alignment it out. Yep pellet clipping.

          For a silencer to work right it has to be designed and made right.


          • GF1,

            The other thing to consider is any + or – effect on air turbulence on the pellet, not just the ability to reduce noise. Like you say, they have to be made right.

            I used to think that louder and no baffle is better, but that baffle insert that I put on the Maximus seems to be doing better. Since it is open in my application (it is meant as an insert), the baffle unit does not quiet, but it does remove air turbulence to some degree.

            Lots of thing to consider and test when messing around at the muzzle end.


            • Chris
              You got it. That’s why I have always said that a air stripper has to affect a pellet on a air gun.

              That’s why I like a shroud better than the muzzle brake type of silencers like the Urban uses.

              The shroud sends the air back more quickly behind the pellet than the muzzl brake type. The quicker the air is relieved the less it will affect the pellet.

              My next choice after the shroud type would be a air stripper type like your using on your Maximus and like the Air Venturi stripper also.



                • Chris
                  I would like to know more about the Air Venturi stripper.

                  Especially about how you said it slides forward or backwards to change the air flow.

                  I think it is probably a bit tricky to set. But when you get there it will be noticed.

                  Like you said I think you need to experiment more with it.


                  • GF1,

                    It is easy to adjust and use. It just did not cause any improvement over the stock muzzle cap. The other one did as far as I could tell with limited testing. Plus, the AV is like adding a muzzle weight and probably changes the barrel oscillations,… maybe.


                    • Chris
                      So maybe the Air Venturi stripper has multiple benefits.

                      Maybe I’ll get one and try on my Maximus.


                  • GF1,

                    The AV has that brass insert/cone that is held in place with a set screw. It is all metal. It has some weight. It has 13mm of fore and aft adjustment. The “gap” at the rear of the cone is 3 – 16 mm depending on where the cone is set. I took a fine marker and checked it at 5 equal spacing’s. I do not remember right off now, but the POI changed significantly with the stock Maximus muzzle cap, the Crosman insert and the AV. It could be the barrel band would need moved again in conjunction with the AV to find the optimal setting?


                  • GF1,

                    I meant to add,.. there is a nice machined groove in the brass sleeve. That is where the set screw grips. That is what limits the movement to 3 – 16 mm. rear gap. As I recall, the barrel threads do not make full use of the stripper threads, so there is some exposed ID threads in the stripper before the pellet enters the cone. Not ideal for an adjustable cone I would think.

                    You could not use the groove, but the further back it goes, the less it is in the outer housing and might cause misalignment. The back edge of the cone is quite thin and one “clip” would almost certainly destroy it.


                    • Chris
                      You have the hunter model of the Maximus. So yours has the threaded muzzle piece.

                      My Maximus is the standard model. So if I got a air stripper I would need one that slips on and is held with a set screw.

                      I need to see if one is available like that.


              • GF1,

                From what I’ve seen online, your Gauntlet has a set of clam shell formed baffles inside the shroud. I don’t think that they are attached to anything. They just sit on top of a stripper that is pressed onto the actual barrel. In one video that stripper was split from being pressed on crooked or something. I guess as long as the shroud gets attached parallel to the barrel the baffles will stay out of the way of the pellet as it passes through, but poor assembly practices could cause clipping in this shrouded design ,as well.

                Half



              • Yogi,

                In a firearm suppressor the holes are very close to the bore size. In an airgun version I would think they could be more open. The shank of a 5/16″ (.3125″) twist drill will slide down the length of my Urban’s silencer. That’s why I think it may just be canted to the side a little. The whole assembly seems to be attached by a point about 1/2″ long and it’s plastic. Great pains are taken to get the treads on the muzzle and inside the suppressor parallel and square in a screw on silencer so that no clipping takes place. It is also made with metal, which is more rigid. These guns ( Coyote and Urban ), in their BSA embodiments have a threaded on air stripper to cover up the silencer threads when it’s not in use. I guess that’s what they molded or crimped the Gamo silencer to.

                Half


              • Yogi
                Like Halfstep said about firearms and hole size close to the size of the bore. Also true for air guns.

                And think about the question you asked. How could one size fit all be the best. They will probably work. But not work as efficiently as they could.


              • Yogi,

                That is tuff to say. The AV stripper did not work well and I would say it is very tight. With a LDC, they can be doing 2 things at the same time. They can quiet the report and at the same time reduce/confine/restrict air turbulence. The Crosman baffle is bigger ID at the rear and goes smaller the further it gets to the tip. Of course, because it is not contained, it does nothing to quiet the report, but does seem help accuracy. The Crosman was like 5$ and the AV was like 35$, if I recall correctly.


          • Gunfun1,
            I have a Walther CP 88, with an after market adapter and LDC, that clipped the pellets so badly that they were cut in half! Without studying the problem at all, I drilled a bigger hole in the LDC. The gun shot better but the LDC was ruined! It now shoots just as loudly with as without the modified LDC. The up side in my case is that the LDC and adapter are removable. The down is that I have spent close to $100 for nil.


            • Ton
              Yep exactly. If they are not made right why even have one.

              By the time you drill it out so it don’t clip you lost everything that it’s suppose to do.

              And yes that too. Bummer you spent the money for nothing. As it goes. If something is to be done. Do it right or don’t do it at all. Only if the manufacturers would learn this.

              I say don’t have a option available if it’s not going to work right.


        • Yogi,

          It looks as if the silencer is over molded or crimped onto the tip of the muzzle at the point where a screw on silencer would go. This would give the whole thing the chance to lean to one side. The large diameter of the holes could be allowing the pellet to pass through the first baffles and only clip the last one.A cleaning rod stuck down into the barrel could be used as a guide as you push the silencer into a better alignment after it has been warmed with a hairdryer. That’s what I would try, if it were mine.

          Half




              • Halfstep,

                Thanks for the correction. Yes, I knew that but short AM and PM reading has me rushing through comments and thoughts. The thought (at the time) was that the shroud was pinned to the barrel.

                This is what I bought to add to the Maximus:

                https://www.pyramydair.com/search-results-ext?Ntt=py-a-7784&sid=1375A617A415&N=0&Ntk=primary&q=py-a-7784&cx=002970863286801882398:jlcminxfwdw&cof=FORID:11;NB:1&saSearch

                Screw off the muzzle cap on Maximus and screw this on. It does not quiet anything, but it does seem to help with air turbulence and accuracy improvement. Also, since this appears to be an insert for a Crosman NP, I am assuming that screws onto the barrel as well, but goes inside a shroud of sorts.

                I do understand what you are saying with regards to FFL and such.


                • Chris USA,

                  I think the way the shroud attaches to the NP Trail is permanent enough and integral enough to that specific gun to get around the tax stamp requirement. The baffles have to be inside a tube to silence anything so they aren’t a silencer and don’t require a stamp. But I bet if you also owned a tube, threaded to fit your barrel, that would accept your baffle assembly, the ATF would have a problem with that.

                  When you say that the baffle assembly threads onto the barrel, does that mean that the front sight is just screwed on the Maximus barrel?


                  • Halfstep,

                    The Hunter version has no open sights. I am not sure if PA offers it. If not, go to the Crosman site for a view. There is a metal “cone” on the end with male threads and a plastic cap. I tried to get the cone off, even with heat,.. and it will not come off,.. just as an fyi. Why did I try to get the cone off? I wanted to try it with no barrel band,… without tearing it apart.


            • Chris USA,

              I doubt that you would really want the hassle or the expense involved in owning a threaded one in America. That’s why it is permanently attached to the barrel. Only way it can be sold without a FFL holder being involved with the transaction.

              Half



        • B.B.

          I really am hoping you can resolve this issue and continue the test. I am going to be very disappointed if you are unable to continue because of this baffle problem. Shame on Gamo for allowing defective product to leave the factory.

          Are you listening Gamo? Get your act together! One bad apple spoils the whole bushel.


  5. I’d return it. If it was used or out of warranty, it looks like maybe one could grab that thing with the needled nose on my Leatherman, and jerk it out?


  6. BB,

    If you get the baffle issue resolved, you might try H&N FTT 5.55 head size. they are a 1″ at 50 yard pellet in one of my guns.

    At the end of “What Next?” should be “It’s all moot, though, because….”

    Half


  7. B.B.,

    Hopefully Pyramid Air permits you to tear into it (cap pins) and drill the baffles out a bit. Or, just straight out drill it. At this point, there is nothing to lose. If this was an early production model, the baffle I.D. might be different from the current production run? It is obvious though that Gamo needs to have the I.D. opened a up some more. It is obviously too close to the (work/not work) point at this time

    Good Day to you and to all,….. Chris


    • Chris
      That’s exactly the thing that a manufacturer has to be aware of. It’s better to err to the big side of the diameter of the hole in the baffle and make the gun a bit louder. Than go to small on the hole and have accuracy problems.

      From what I have seen and heard of. Gamo don’t have very good quality control. Maybe they should of stuck with the BSA side of of the company. The silencer is definitely Gamo. And the gun is definitely BSA. I myself lean towards BSA 100% more than I do the Gamo side of manufacturing.


  8. BB,

    As soon as you told us you had a pinwheel with the Air Arms Diabolo Field, I knew what the problem was. PA will probably tell you to go into it and fix it, most especially if Gamo is as easy to deal with for them as my experience has been. If I had an available room for another air rifle right now, I would make an offer on that one and tell you to go for it.


    • R.R.
      Got my sports match adjustable rings today, very nice. However the UTG rings with the picatiny to 11 mm adapters placed the scope about a 5/16 above the receiver. The sports match were only about an 1/8 above the receiver. I like the extra clearance and at 50 yds zero with equal height rings I’m only 4 revolutions up on my vertical adjustment. So I’m gonna go back to the utg rings on my TX and put the sports match on my .22 hw 50, it needs some help in this dept. It’s a shame though I liked the idea of English rings on an English gun and I like the roll pin scope stop. What clearance do you have between your TX and the objective bell with the sports match rings?


      • Carl,

        I do not have a TX. That is a very nice sproinger that I have so far managed to resist buying.

        I have my UTG Bubble scope mounted on a .357 RAW HM1000X. I have somewhere under a half inch clearance between the objective bell and the barrel. I shoot this air rifle at 100 yards, so the adjustable mounts help me to still have usable mil dots out that far.

        If you feel like you need more clearance, you can adjust the front mount up also. I myself would not mind only a 1/16 inch clearance as long as my eye is in the right place when I sight.

        This is something else I use for droop compensation on my sproingers.

        https://www.pyramydair.com/s/a/Hawke_Sport_Optics_1_Pc_Elevation_Adapter_3_8_to_Weaver_Rail/4163

        I also have a longer version of this, but it appears PA is no longer carrying it.


  9. BB,

    I am curious as to whether the baffle assembly will move. Have you tried using something to see if it will move over?

    Halfstep mentions that the baffles are in two halves. It may be that the two halves were not properly assembled when inserted. GF1 is correct. Good quality control would have noted the baffle assemblies were misaligned. All you have to do is take a look at the muzzle.


  10. The problem with moving it without removing it is it could move back to interfering with the pellets. As mentioned earlier, if you drift out the 2 pins in the end cap the baffles will slide right out. I don’t think it’s a bad design, they are made to stay centered in the housing. I just think B.B. got a bum gun.

    Speaking of keeping guns silent, has anyone tried to quiet the action of the Urban at all? I think a good bit of the noise from my gun is from the hammer hitting the stop when it’s fired. I have read on GTA about putting an o ring or something similar in between the hammer and the block to cushion the impact. This is usually talked about in the context of limiting hammer bounce, but also hushes the action. Has anyone tried this with our Urbans? If so, would the gun have to be degassed to access the space between the hammer and the valve?


    • Toddspeed
      It’s a good idea does sure. Just a shame it has to be done to a new gun.

      The thing is it might of left the factory and the baffle was aligned. Then shifted while in use or even transporting. That’s another question. How well does Gamo box them. But there were go again sounds like a bad design of the baffle fit to the outer case of the silencer.


    • Toddspeed
      Forgot to say. I have done it on Marauder’s and the o-ring mod works.

      The Urban I haven’t but should work if you have the place to put it in.


      • Thanks for the input.
        This is my first PCP, I’m thinking I should not have to degas. But, I’d like to know if you had to degas your Marauder to put the o ring in it.


  11. I say send it back. There’s nothing more embarrassing for an air gun manufacturer than having a nationally-recognized reviewer have to send their gun back because of a mechanical defect. That should definitely improve the quality control for the rest of us.






        • You are correct. I worked in quality for over 40 years in a manufacturing environment. We used something called an AQL, which is acceptable quality level based on statistics. I always viewed it as the willingness to ship inferior, or defective product to our customers at an allowable percentage level. We had one manager whose theory was that the quality of the product was acceptable if it was shipped out, and was not returned. I added a corollary to his theory; if the product doesn’t come back, but neither do the customers. We manufactured hydraulic pumps and motors for industrial and mobile applications. I used to tell people who were going to fly, “If you look out under the wing and see red fluid GET OFF THE PLANE!” The quality level in our plant regressed to a point I could not stand to work there anymore, and retired. Wish I didn’t know now what I didn’t know then.


        • TT,

          I’d think they have to. Can you imagine the time and man hours that would be required to thoroughly test all aspects of every gun over a statistically significant period of shots, which is what it would take to insure that every gun left the factory in perfect working order. Even this doesn’t eliminate something going awry in the trip overseas.

          I worked in manufacturing for 42 years and if mass producing airguns is anything like appliance manufacturing, a certain sample size will be pulled at certain intervals and put through long range( time, not distance 🙂 )testing to flush out design defects and chronic faults. They probably have a set of QC checkpoints that can be done quickly with automation or by the assembler at various assembly stages. I think that the BSA factory, where these are probably made, does all that they practically can. If this baffle issue is widespread I think it will be addressed.

          For now I vote, Debaffle the thing. I want to see some feedback on how it sounds sans silencer anyway.

          Half


  12. B.B.,
    I hope they send you a different rifle. I am very disappointed in Gamo’s quality control. You would think these issues would be caught. Like on the Umarex gauntlet having a bad magazine. Do they not get function tested? But, if the manufacturers arr willing to make it right, I can forgive them. I read all kinds of stories where some companies don’t seem to want to do that. I sent one off before and it came back just like it left.

    Doc


    • Doc,

      Gamo didn’t send me this Urban. It came from Pyramyd Air.

      I am not interested in a replacement. That just means someone else could get a bad gun, too. Not that PA would resell this one without fixing it, but any one of them could be bad.

      I need to find out what is wrong and what can be done about it — if anything.

      I think the rifle I’m testing is probably very accurate. This baffle is just in the way.

      B.B.


    • Doc
      About the magazine on the Gauntlet. I don’t think I would call it bad or should I say different. The Marauder magazines as well as the FX Monsoon mags that look identical have this same issue.

      I think they don’t have a good standard of what the magazine should be held at design and tolerance wise. And the thing about it. That’s another problem. With these types of magazines you can physically see error in location of the pellet as it’s ready for that particular time to shoot.

      With the round clip kind like some of the Hatsan’s and like the 1077 and WildFire use. Is you can’t see if there is a alignment issue with them because they are inserted in the breech. But I do believe the same missalignment is there from the guns I have had.

      So that was my round about answer of saying that the manufacturers don’t think there is magazine or clip issues. So they don’t even have a idea they need to look into the situation. I believe they think there is no problem.


      • Gunfun,
        I understand. But I think those too should not be that way. I have had more than one Crosman .357 C02 pistol that the circular “clip” was not right. I would get a flyer and wonder why. Finally I studied the gun, “forcing cone area” and the recovered pellets too. Pulling the hammer back, then carefully unlatching the top of the barrel, I’d look and sure enough, the pellet wasn’t always aligned. I found one or two pellets not lined up in different clips. I never had a 10 shot “clip” to see if it were any better. I always blamed the gun back then, but I see now it was probably the clip.

        Doc.




  13. BB
    I know you don’t need my input but here it is anyway. I would put a small punch in the baffle end and see if it will move back to centered. If so add a drop of epoxy to keep it there. The baffle seems to have been in alignment when you started testing so it may just need an adjustment.
    I agree with others here that it should not need to be worked on so soon but that is my idea for a simple fix.
    Gerald


  14. ALL,
    Do you feel like the 10 for $10 or 20 for $20 would have caught this? I’m not saying you should have to pay to find a defect, just wondering if it might have. I know PA and I’m certain if someone would have bought this and couldn’t have fixed it themselves, PA would have made it right. When my friends asked me if they should buy airgun X from ABC company cause it is a few bucks cheaper than everyone else, I always say, buy it from PA. They’ll stand behind it.
    Doc


    • Doc

      Looks like it did not fit tight enough and shifted . A 10 for $10 might not have caught this .
      Maybe a “beer can tune” could fix this . Wrap the baffles with enough cans to keep it fairly close to center.

      tt


      • TT,

        I have done just that when pulling baffles and replaceing with bronze bearing weights,.. except I used masking tape. Scotch tape would be somewhat thinner and allow for a more “refined” fitting. If they are loose, I would go that route. If they are good fitting, I would enlarge the ID.


  15. BB,
    I second Siranko’s advice on shooting this gun until accuracy improves. second that. I have a Gamo Swarm that sprayed pellets like that and that is exactly what I did. It basically settled in after about 200 shots. The pellets I used was the Predator GTO .22. They are harder than lead so that may have accelerated the clearing of a pathway through the baffles. But I don’t think you want to spend so much time on this test lol.


    • Ton
      That is true. But if you shoot like that to clearance the problem. That means you are really close to hitting it every shot. And I mean really close.

      All that’s going to do is come back and bite you.



  16. Gunfun1,
    That’s true no doubt. I will widen the LDC channel one day. I am good at fixing things that don’t need it and bringing grief on myself lol. A silent gun is important to me since I blew out like 95% of the hearing in my right ear after firing a 2240 indoors. It is the only springer I have that is baffled for I don’t find them to be loud. This one is quiet though.


  17. Gunfun1,
    Ear protection definitely recommended particularly for indoors. When I asked my ENT why permanent hearing damage should occur after this particular shot whereas previous sessions did no damage. He explained that the circumstances and situations under which this could happen. 1. Assuming a stress position (such as leaning over heavily to one side while shooting. 2. Shooting when you are suffering from the flu (or soon after) when the inner ear is infected as a result. The later appears to be my case.
    Now I do no shooting when I am down with the cold. A second opinion from another ENT recommended I give up the shooting sports. My response:
    “Ah Doc, I will get silencers for my guns” He just looked at me without comment.


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