by Tom Gaylord, a.k.a. B.B. Pelletier
The Lightweight Disco Double in its new stock looks striking!
Okay, all joking aside — today, we’ll look at the performance of the Lightweight Double Disco that Lloyd Sikes built. Lloyd tested this exact rifle when it was still in its factory original condition, so we can compare that to the performance of the rifle after the conversion. I was pleased to see that my chronograph results and Lloyd’s are very close.
Before the conversion, the stock Benjamin Discovery accepted a fill to 2,000 psi. From that fill, the rifle got 21 shots of .22-caliber Crosman Premiers at an average 845 f.p.s., which works out to an average 22.7 foot-pounds. Lloyd did get more shots in his string, but he discounted all those that were not within 4 percent of the average velocity. That’s a subjective choice, but it’s what drives the numbers Lloyd is giving us for the factory rifle. The maximum velocity spread in this string of 21 shots was 40 f.p.s., with a low of 820 f.p.s. and a high of 860 f.p.s.
After the Lightweight Double Disco conversion, Lloyd shot the same Crosman Premier pellets on a similar 2,000 psi fill and got a string of 33 shots at an average 849 f.p.s., for a muzzle energy of 22.9 foot-pounds at the average velocity. Again, this number includes all shots that fell within 4 percent of the average velocity. The maximum variation in this string of 33 shots was 34 f.p.s., with a low of 831 f.p.s. and a high of 865 f.p.s.
The shot count made possible by the Lightweight Double Disco conversion went from 21 to 33 shots. The average velocity did increase by 4 f.p.s., but I wouldn’t concentrate on that because these numbers will change a little each time you record them. Essentially, the gun shot this pellet the same before and after the conversion — it simply got more shots after.
What did I get with Premiers?
I filled the rifle to about 2,100 psi because I wasn’t sure that my best pressure gauge agreed exactly with Lloyd’s gauge. I wanted to start in a slightly valve-locked posture and move up into the power curve as I went, and that’s exactly what happened. Here’s my shot string.
1-20 21-40 41-end
802 856 836**
822 856 832
817 852 828
826 852 825
831* 857 824
831- 855 820
833 857 816***
837 853 STOP (47 shots)
842 853
842 860+
846 853
848 855
849 848
852 848
850 842
851 848
852 840
851 843
847 838
851 839
– Slowest shot in acceptable string
+Fastest shot in string
* First gauge photo
** Second gauge photo
*** Third gauge photo
This is where the needle was just before the fifth shot in the string was fired.
This is where the needle was after 41 shots had been fired.
This is where the needle was after 47 shots.
If I accept the shots in this string starting at No. 5 and continuing through No. 41, I get 37 shots. They’ll have a maximum spread of 29 f.p.s., with a low of 831 f.p.s. and a high of 860 f.p.s. If I’m more critical and start with shot No. 8, which went 837 f.p.s., and still stop at shot 41, the total is 34 good shots, with a maximum spread of 24 f.p.s. The low in this string is 836 f.p.s. and the high is 860 f.p.s.
Do you see how this works? It’s entirely subjective. I’m deciding what to accept and what to reject. Once I start accepting shots, though, I keep on shooting until the last shot in my acceptable string has been fired. I can’t ignore any shots in that string because I won’t be able to chronograph my shots when I’m shooting in the real world, away from the chronograph.
You must pick the starting and ending points that you feel are best for what kind of shooting you want to do. That’s why a chronograph is so essential to the owner of a PCP. If I were to shoot this same string again with the exact same starting pressure, which is very difficult to control, I might get numbers that are similar but slightly different from these.
Baracuda/Beeman Kodiaks
Next we will look at the performance with .22-caliber H&N Baracuda pellets. Lloyd tested the rifle with them, but I didn’t have any .22-caliber Baracudas on hand, so I substituted the Beeman Kodiak, which is the same pellet under a different name.
With the Discovery in factory trim on a 2,000 psi fill, Lloyd got a string of 22 shots that averaged 717 f.p.s. They produced an average muzzle energy of 24.2 foot-pounds (compared to the 22.7 foot-pounds produced with Premier pellets in the factory trim). Heavier pellets will almost always produce more energy in a precharged rifle. The maximum velocity spread with the Baracuda pellet in the factory Discovery was 29 f.p.s. The low was 697 f.p.s. and the high was 726 f.p.s.
The Lightweight Disco Double conversion running on the same 2,000 psi fill with Baracudas gave a string of 38 shots that averaged 713 f.p.s. The low was 699 f.p.s. and the high was 729 f.p.s., so the spread was 30 f.p.s. The average muzzle energy was 23.9 foot-pounds.
Baracudas got more shots per fill than Premiers
With Baracudas, Lloyd got 22 shots per fill in factory trim and 38 shots with the Lightweight Disco Double conversion. In both cases, the rifle gave more shots per fill with the Baracudas than with the Premiers. My thinking is that the heavier, slower pellet holds the valve open a bit longer and is able to go to lower pressure before it falls off the power curve.
What did I get with Beeman Kodiaks on a 2,000 psi fill (refer to the first photo of the pressure gauge to see where I actually stopped the fill)?
1-20 21-40 41-end
702 712 701
699- 720 693
707 716 695
714 718 696
709 714 683
719 726 STOP (45 shots)
717 728
711 725
723 722
718 709
711 709
715 712
728+ 708
728 716
712 721
716 711
717 718
719 715
724 715
718 707
– Slowest shot in string
+Fastest shot in string
While this string has fewer shots than the first one with the Premiers, there are actually more usable shots here because I learned where the needle on the gauge had to be in the first test. No air was wasted at the start of this string. I would accept everything from shot No. 1 through shot No. 41, giving me a total of 41 usable shots, with a spread of 29 f.p.s. The low was 699 f.p.s. and the high was 728 f.p.s.
I got more usable shots from Beeman Kodiaks than from Premiers, just like Lloyd did with H&N Baracudas. Our data seems to agree very closely. Lloyd’s low velocity was 699 f.p.s. and so was mine. Lloyd’s high was 729 f.p.s. and mine was 728 f.p.s. How is that for consistency? As I said, the H&N Baracuda and Beeman Kodiak are the same pellet.
Analysis thus far
The Lightweight Disco Double increases the useable shot string significantly, even though the rifle is no larger nor heavier than a factory Discovery. You can tell from a glance at the onboard pressure gauge if the rifle is still on the power curve, so there’s no need to count the shots.
All of what you have seen to this point was done with the stock Discovery striker spring (0.035″wire, 0.289″ OD, 1.99″ long , 16.5 coils) in place. But Lloyd also provided and tested a heavier striker spring (0.041″ wire, 0.300″ OD, 1.78″ long, 19 coils) that gives both the factory Discovery and the Lightweight Disco Double conversion more power.
To see what the heavier striker spring can do with Baracuda pellets in the Lightweight Disco Double, Lloyd recorded that the average velocity climbed from 713 f.p.s. to 764 f.p.s. That is an energy increase from 23.9 foot-pounds to 27.5 foot-pounds. The total number of shots dropped back from 38 to 25 shots. This shows how the Disco Double allows the power to be increased, and the total shot count to remain the same as the less powerful factory gun.
Trigger
I haven’t reported on the trigger, yet. You may recall that I had Lloyd install an optional trigger from a Benjamin Marauder. Lloyd told me in a message that it’s set for a light first stage, and then an extremely light second-stage pull. I found at first that it was so light that I pulled straight through both stages without recognizing stage 2. But when I adapted to it, it’s really not as sensitive as a 10-meter target pistol trigger. Stage 1 takes 14.4 oz. of effort; and stage 2, while recognizable, does not increase the number on the electronic scale. It’s on the order of 10 grams or less.
Summary
So far, I’m delighted with the Lightweight Disco Double. If it turns out to be accurate, it could become my go-to PCP!
I like that it has a very consistent power curve. Its almost acting like the gun has a regulator installed after the dual reservoirs were installed.
And the gun is make more power and getting more shots with the heavy spring installed than a stock Discovery with the single tube and stock spring.
I’m glad both results happened. Now for the big question.
lloyd
Are you planning a double tube conversion for the Marauder rifles? My .25 caliber Marauder would be a very happy gun if it had dual reservoirs. Then I could turn it up and use it the way I would like and still get a fair amount of shots. I have the gun de-tuned for every day shooting. But if I go in to the woods I have my allen wrench with me for the striker spring if I need to turn up the power. I leave the striker/hammer adjusted for full stroke.
So I don’t know if you got anything in the works for the Marauder rifles. But I would think they would make for a good candidate for a conversion also. If you prototype one for a Marauder rifle and need somebody to test it I would be more than happy to. I will even pay you for it. Even if its the only one you ever make. 🙂
GF1,
Sorry for not answering yesterday, but I was away from my computer all day.
A lot of people have asked about something for the Marauder and I am seriously considering it. Someone already makes a steel extension tube for the Marauder that just screws right onto the end of the main tube. It works well, but it adds a lot of weight on the front end of the rifle.
Part of the issue with adding a second lower tube to the Marauder is the depth of the stock at the very front end. Adding a second full size 1-1/4″ tube like is on there now would break out of the bottom of the stock about 6″ from the front end. In aluminum, it would add about 195 ccs (and 12 ounces) to the 230 that the main tube holds. Another option would be a 1″ diameter tube which would just barely break out of the front end of the stock. That would add about 125 ccs and (8 ounces).
I think the 1″ tube is the more viable option, but I am always listening for suggestions.
Lloyd
Lloyd
The small diameter tube would be just fine for me.
I have a extra Marauder pistol trigger assembly that always has the 1399 Crosman custom stock on it. So sometimes if I’m going to take the. 25 cal. Marauder out for a day or weekend of shooting at my brothers house. I will take the wood stock off and put the pistol trigger and stock on the gun. It makes it a little lighter and easier to carry for me it seems anyway. So the stock isn’t a concern for me. I will leave the gun set up that way when I get one of your tubes installed.
I will go to your website and leave you a message. And thanks Lloyd.
I thought I would post this in case maybe other people would be interested.
I did talk to Lloyd this morning on the phone and thought I should share this info. And I thought again because its something new and I didn’t know if I should really comment about it yet. But here it goes.
He is going to make me a 1″ diameter aluminum tube kit that I could add to my Marauder rifle with the band clamps that will be needed for the Marauder rifle. Its going on my .25 caliber Marauder when he gets it made.
He has to make some design changes and he said he would let me know when he gets it planned out. I’m kind of excited because he said you know this will be the first one. And you all know me. But all I can say is I can’t wait for this to happen.
And again Lloyd thanks for taking the time. And I couldn’t resist commenting. I hope that was ok.
GF1,
That is fine. I studied the standard Marauder barrel band, and if you twisted it around so that it hung off the bottom of the front fill adapter (instead of sticking up to contain the shroud), and bored it out to 1″, that could grip the new lower tube. But then you’d have nothing protecting the shroud if it got bumped hard. A thought anyway.
Lloyd
Lloyd
I was wondering if that was going to work out ok.
And I probably wouldn’t care about the shroud so much not having something there to protect it. But remember I got my shroud and barrel truly floating. I got thinking about that after we talked. Maybe it will be better to have that extra bit of protection around the shroud incase of the hard bumps like you say. I think it would probably make people more comfortable having that protection there. I know more work for you to design and make it. But it will probably be better in the long run.
So I guess that means that it should work out then for the Marauder. The band clamp being the big issue? Other parts of the kit should work out then I guess from what you said yesterday when we talked. Right?
Might look silly but… there’s already a fitting for the pressure gauge — what if one removed the gauge and just fit an extension tube that stuck straight down? Put a rubber foot at the bottom end at it might double as a monopod support.
Wulfraed
I don’t know if you get Shotgun News. But on page 106 of the Feb. 3rd. 2014 issue there is a picture of a vintage Crosman CG Model 101 pneumatic rifle. The description says that Crosman modified it to accept a 4oz. surplus C02 tank.
Guess where it is mounted. Straight down about right in the middle between the trigger and wood front grip. And it looks to me like its about 3″ in diameter and about maybe 8″ long.
Who knows maybe certain people would like something like that and it could maybe have something like a rubber grip slipped over it and you could use it like a vertical front tactical style grip.
Wulfraed,
Silly looking or not, that is a great idea, and it would be so easy to do. Just a 1/8″ steel pipe nipple (rated for adequate pressure) and a tube with a pipe thread in the end. That would really work well on a bullpup, too, by putting a new hole in the bottom of the tube forward for a front grip.
Lloyd
Of course the next variation is a harness mounted SCUBA tank, hung upside down, with a suitable high-pressure rated hose attached through the opening (and maybe a high-pressure regulator so one can dial the tank into the optimal fill pressure). <G>
Wulfraed
If I remember right I think that very thing was brought up when we had our conversations about the 100 dollar PCP gun.
A bit off topic here….
Is there any way to shorten the second stage in the AA S500 ? I looked around the web and could not find much info for adjusting the trigger. I have a long and creepy second stage.
twotalon
twotalon,
Here’s a pretty good tutorial on tuning the AA S4XX/5XX triggers. If you decide to polish the sears with a dremel and toothpaste/brasso go easy.
http://www.shootforum.com/forum/s4x0trigger.html
kevin
kevin….
Thanks. That gives a much better description than the book does. The book does not include the actual procedure. I have no intention of taking it apart and messing with it. Only interested in HOW TO adjust the thing at this time.
twotalon
twotalon,
Didn’t know you got one of those “things”. LOL! Congratulations.
The AA S4XX/5XX triggers can be adjusted to one of the best sporting triggers out there. Almost infinite adjustability. The side to side play is common and the washers or an aftermarket trigger from Rowan make a significant difference. I installed a Rowan in my S410 years ago. I’ve had a lot of pcp’s come and go but the S410 is still here. Hope you enjoy your 500.
kevin
kevin
Got it set up. Thanks again. Feels good. Hopefully the barrel will be good with no extra work required.
twotalon
twotalon,
Mine was new from the factory years ago. I had to clean it with B.B.’s jb bore paste method. It was greasy dirty and shot all over the place. Haven’t cleaned it since and it’s still very accurate.
If yours is a .22 caliber make sure you try the jsb 15.9gr and 18.1 gr pellets.
kevin
kevin
If it shotguns, I would like to clean it. Is it hard to pull the barrel so I can do it the way I want to ?
I don’t know how to get it apart. I WILL NOT do it from the muzzle.
twotalon
twotalon,
Shoot it first you may not have to clean it.
Never had the barrel off of mine. I cleaned from the muzzle with a soda straw for a guide and a dewey rod. I have also ground down the sides of a .22 caliber brass loop that holds patches so it fits into the bores of my guns easily. The brass brushes I use fit fine without modification. Cleaned many guns from the muzzle this way.
kevin
kevin
I will do a pull thru a couple times with CLP and try it. That’s about all I did with my 97K.
If it looks ragged, I will try to get it apart. I have my own methods of doing things. Hope this goes easy.
Won’t know how it does outside very soon. Don’t want another bad LW barrel. Still cold here.
Rough bore or corckscrewer not welcome.
twotalon
Also
I have about every pellet from JSB except the 18 gr. .
twotalon
I’ve had my S500 for about a year now. It is one of my 3 or 4 go to guns. (I have more than one). The trigger on mine was very short and light when I got it. I have found mine to be sensitive to fill pressure (light valve lock). It seems to be best at about a 2700 or 2800 fill pressure.
Have fun with it. I love mine.
G&G
G&G
I will burn a string or two over the chrono to figure it out about half way as soon as I get my pellet trap back from my wife. She has been using it in the living room with her Nighthawk .
Need to get a longer hose for the pump. P.A. has some two footers that should work.
twotalon
Nice tutorial, Kevin, thanks! That link is going in the favorites!
/Dave
/Dave,
You’re welcome.
kevin
B.B.,
The Disco Double conversion seems to be a very good idea.
I agree with your comment about chronographs. I’ve learned a lot shooting over one.
It’s already been suggested, but I wonder how many shots the Disco Double could manage with CO2.
From a man who owns many air rifles, your comment, “it could become my go-to PCP!” surprised me.
As always, thanks for another great report.
RB
RB,
I didn’t say that lightly. The Disco Double is a single shot, which I prefer always. It has a wonderful trigger, which puts it slightly ahead of the Talon SS. The power and shot count are fine. If the accuracy is also superb it will be hard to beat. At this point the Talon SS is my go-to PCP.
B.B.
RB,
My Benjamin Katana (same air tube and valve as the Discovery) gets about 60 shots on CO2 with no special charging process. I would expect the double-tube version to get around 120 shots.
Paul in Liberty County
Paul,
What velocities/fpe do you get with your Katana on CO2? Is the rifle significantly quieter on CO2 than HPA? I’ve never used CO2 in a PCP rifle, and would like to try it in my Discovery when the weather warms up.
You have an interesting and unique rifle.
RB
RB,
I did a guest blog a while back covering those very questions. The gun is quieter using co2 – maybe 60% as loud.
/blog/2010/05/the-benjamin-katana-on-co2/
Paul in Liberty County
Paul,
Thanks! That was a great write-up on shooting with CO2.
RB
Good report, but I have to wonder what the advantage is of a double disco? When you pay for the conversion, and better trigger, wouldn’t it make more sense to get a marauder? You have a good number of shots because of the higher pressure, the better trigger out of box, noise shroud, and still with the advantage of tuning power for fps/shot count balance. It seems we are just trading higher pressure for higher volume…
Mark,
For starters, this is a single shot, which I prefer. I can shoot anything that will fit, rather than being held hostage by what the magazine will accept.
The Marauder gets lots of shots, but the Disco Double is ahead of it.
As for the noise, I have yet to try the TKO silencer.
I don’t understand your last comment. The Disco Double runs on lower air pressure and gets a higher shot count.
B.B.
Okay, I had to go dig through some past reviews to answer my own feeble-minded questions. The question in my mind was whether we were using the lower-pressure-but-higher-volume (126cc x 2) of the Disco double to slightly increase the shot count as compared to a higher-pressure-but-lower-volume (215cc) Marauder. Short answer is no. In your past reviews you were getting ~23 shots within spread from a .22 Marauder (albeit at a much higher 863fps velocity), you you are indeed getting significantly more shots from the Disco Double. You would know better than I whether the Marauder could be tuned down to to 710fps velocity, and what shot count would be like if you did.
I will go to the back of the room and be quiet now, please continue… I will take notes…
Mark,
To answer your question, I ask you to pick each rifle up and shoulder it. Totally different guns. The Discovery is light and maneuverable and you can tote it around the woods all day. The Marauder is a much larger and bulkier gun and is 50% heavier. That is significant. The Discovery can easily be tuned to give the same power, and with the double air tubes, the same shot count, as the Marauder.
Lloyd
That’s a really nice result! I like my AA S410E for power and number of shots, and my Discovery for its lightness. This conversion puts the Discovery right up there with the S410E for power and number of shots too! I can’t seem to get the accuracy of my Air Arms, but that may be due to the stock trigger in my case. Even so, it’s accuracy is nothing to sneeze at and its not a gun that I’m embarrassed to own.
/Dave
BB
This is off topic.
Do you by chance know what month your article of the SHOT Show will be in Shotgun News?
GF1,
It will just be a column — not a feature article. It will be in the third issue in March, which is a color issue. I also have a full feature article on the new AirForce Escape rifles in that issue.
I should hit the newsstands around March 10.
B.B.
Thanks BB I don’t want to miss it.
It could be that the Discovery will be one of those guns that really blossoms with aftermarket accessories. That can be a very important niche as we see from the Ruger 10/22, the AR-15, and the Remington 700.
I have tragic airgun news to report. My Daisy 747 broke the other night! There is no tension on the cocking lever at all and it will not hold any air. Surely the seals did not fail so catastrophically that fast. That’s it. I’m going to buy Russian from now on which never fails. My Mosin-Nagant never ever fails to extract, and it is more reliable than both the Mauser and the Lee-Enfield. And my IZH 61 (with which I consoled myself) keeps running flawlessly. So, I’m thinking of the IZH 46 (the target pistol). Too bad it costs a fortune at over $300. How very un-Russian. Also, is it possible that the seals can fail on it as well as any other kind of gun? Also, it would be a shame to give up Derrick’s fantastic trigger job that he put in, so I’m not done yet.
On another subject, I have an important question that requires some technical expertise. I have a big, deluxe microwave oven that was upper-scale when I bought it in the mid-90s. It’s worked fine, but it’s been 20 years now. Is it possible that the insulation has failed in that time, and I am getting bombarded with damaging rays? When do you know to check something like this and who does that kind of work? Thanks.
Kevin, that business about handguns blowing up reminds me of a dialogue in Clint Eastwood’s film Unforgiven.
Gene Hackman: So then, Two-Gun Corcoran draws his Colt Walker and aims at English Bob, but it blows up in his hand which was a failing common to that model. So, English Bob takes aim real slow…
Report: No, he didn’t…
Gene Hackman: He wasn’t going to wait for Corky to grow himself a new hand…
On another note, how’s this for a radical advance in gun technology. A place called Alexander Arms which has long specialized in modifications of the AR platform has created a new semi-auto .338 Lapua rifle. It’s called the Urfbehlt or something like that which is a Viking word. For some reason, they dropped the AR for this project. The owner said that there are problems adapting the AR to bigger calibers. Instead, for reliability’s sake he built on the design for the old Russian light machine gun from WWII which was utterly reliable like most things Russian. It works great, the guy gets 0.75 MOA at 100 yards and makes reliable hits on a 3X3 foot plate at 1450 yards. The question is what market niche does this gun fill? Who needs a semi-auto at that range? I thought semi-auto sniping was more for a designated marksman on a battlefield with multiple targets. But at a price of $6000, this gun is probably constructed on a custom basis.
Matt61
Matt,
No worries on the microwave unless you’ve bent the door or something. Even then you’ll not likely get cooked. Microwaves use radio frequency electro-magnetic (radio) waves in the 2.4 GHz band. Same as your wireless router only 1200+ times stronger. That radio frequency electro-magnetic radiation is what cooks your food and is contained by a ground metal cage (Faraday cage) that surrounds the oven. The cage absorbs the rf and sends that power to ground instead of out into the room so you can safely watch your food cook. I wouldn’t worry about it even as odd as it is.
/Dave
kevin
First run….
200bar fill. Exact 16 gr . Got 22 shots starting at #4 from 883 running up to 911 and back down to 881 . Smooth curve, no visual flat spot. 30 fps spread.
This is at full power setting.
Will look at CP and Exact RS tomorrow. Will do the CP at full power, and the RS at minimum unless it shoots too slow at that setting. Would like to see 600 fps or a bit better with them. Shoots pretty quiet there.
twotalon
TT
Did you get to do anymore testing?
GF1
Not as much as I had intended , but getting a bit more of the picture.
Did CP (brand new shiny ones) and got a nice humped curve like the 16 gr Exacts did. Same pressure range … 200-150 BAR . Looked like a bit of a flat spot trying to form at the top of the curve . Got 21 shots in a 30 fps spread instead of the 22 that I got with the Exacts . Could be luck of the chrono …insignificant difference. Does meet published velocity (930) with CP .
Tried it turned down all the way after shooting the string (fell off the curve) and got 447 fps . Came up to the second mark and got 660 fps . That’s 25 yd range for a zero on starlings with quite adequate power if I want. So that is as low as I would want to set it with CP .
Have to check out shot count at that setting with CP and RS . Have to see about what the other settings will do with with different pellets .
Want to test Kodiaks too at full power only.
Observations so far….
Curve does not shift with different pellets so far when cranked to max.
Gun needs to be shot in when switching pellets . Takes some shots to get the POI tightened and into one place.
May be a bit early to speculate, but I think it may continue to operate in the same pressure range for all pellets and settings , and produce a similar curve with the peak right in the middle of the string.
Will work on it some more today after I get done with some serious snow removal . Provided I have the energy left.
twotalon
TT
I know what you mean, snow. I think we are making up for those past years of mild winters in my area anyway.
But I wondered if you tested anymore. My 1720T is good like your describing. But my Monsoon was a picky gun with pressure at first. Now its a lot better. I guess the action and cocking mechanism needed to free up a bit and get broke in. If you have to much fill pressure it will not cycle the action and goes by weight of the pellet. I pretty well use a 3000psi fill on it for all the different pellets I use now.
But post if you get more info on your test.
GF1
I could have used a bigger snow blower this time. But did fairly well anyway.
Will see how things pan out as I go. I know what I’m looking for ,but expect to see some different things along the way that will have to be added to the list. Working out most of the gun’s rules before even getting outside for more distance. Will be plenty of time, considering the weather. That woodchuck needs to die.
twotalon
TT
Hmm a pesky woodchuck. Tearing stuff up I would bet. Sounds like you got a good gun for when the opportunity arises.
GF1
Pesky woodchuck and his lousy weather forecast !!!!!
Just ran a string of Baracuda .
The curve didn’t start until shot # 10 this time (same fill as before ). Peak was about at the middle again. Ending pressure same as before, shot count 21 again.
Peak MV 826, 30 fps spread. Still a rounded curve. Power setting MAX again.
twotalon
TT
Oh that woodchuck. Well you still have something to take care of that problem too I suppose. The snow blower. And the gun is pretty consistent then.
GF1
Moved it up here…
So far the curves are looking the same for the three pellets tested , except that the Baracuda starts farther below the starting fill pressure (200 bar).
It is looking so far that when running full power my starting fill should be about 195 BAR with CP and the 16 gr Exacts , and about 190 bar with Kodiak/Baracuda. Keep ending up with the same ending pressure of about 150 BAR.
Have to decide what to do next. Probably a shot or two at around 170-180 BAR with CP and Exacts with the power adjustment at settings 2,3,and 4.
Later, a string of CP or RS at setting 2 to get a look at what the lower power will do to the curve.
twotalon
GF1
Ran a string of CP at setting 2 . Found that it can be a touchy adjustment.
This time, got a downhill string. Not the regular hump curve of high power. This leads me to believe that there may be some setting that will smooth it out into more of a flat line for a ways. Maybe just a bit more velocity than I was getting. Might try it some time.
I started looking on shot #3 at 608 fps and ran it down from there. Going for a 30 fps spread, got 27 shots. At this lower velocity, I thought that maybe a 20 fps spread might be more suitable. That gave me only 14 shots.
twotalon
TT
I was at work and busy so I couldn’t comment back. But I wanted to ask this when we were talking earlier.
When you are talking about the settings and what number you have it set on. Is it like the power wheel on the AirForce guns where it adds or takes away the spring pressure on the striker? Or is it more similar to the Marauder rifles like the set screw on the side of the air tube that adjusts how much air flows through the transfer port to the barrel?
If it adjusts the way the Marauder does then you can definitely change your shot count per fill. And the other beauty of the Marauder is you can then adjust your fps with the striker spring tension and striker travel or stroke I call it. After you have your air flow set to the transfer port. Results are a good power curve that produces a lot of shots and a powerful shot when you get things right.
With the AirForce Talon SS I have found that with the power wheel adjustment all you can do is adjust how hard the striker hits the valve. The valve on their bottles has a fixed spring pressure and the hole that transfers the air to the barrel is fixed. And for that fact the striker only moves a set distance everytime the gun is fired. So there is no way to adjust the flow of air to the barrel other than raising or lowering fill pressure. Or with the power wheel of how hard the striker hits the valve.
From what I see on my Talon SS. The only way I can tune that gun with out taking the bottle a part and changing the spring pressure or the hole diameter in the valve that transfers air to the barrel would be to adjust fill pressure. Is that what you have seen with your AirForce gun?
Tell me but don’t you just love tuning a PCP gun.
GF1
If you go to the page for the AA PCPs and pick one, then look at the pictures of the breech you will see the adjustment. There is a small knob on the right side, and an indicator on the left. It is only five little marks . A very FAST adjustment. This is a transfer port strangler.
I really would not say that this is a way to get an increased shot count. I look at the velocity spread. The slower it shoots, the narrower the spread has to be to maintain the same change in POI. I also consider the useable distance for any particular purpose at any given velocity. Let’s just call it “situation dependent”.
I think I should just consider this to be a 20 shot rifle under most circumstances.
There may well be a particular velocity setup for individual pellets for best accuracy. The adjustment is a bit too fast and easy to move for handling this, so I will have to see how this pans out.
When it comes to the talons, I can’t get a decent curve out of the standard tanks. The high flow Condor tank is another story. It makes a nice “hump” curve.
With the standard tanks, I have to set up a fill pressure and wheel setting that start the curve just as it is just coming to the peak . I look for accuracy more than anything else. Forget the shot count. The power setting and fill pressure that give the best groups is what I use.
I will not bother with going to the extremes that some people do to get shot counts or power.
twotalon
TT
I think some of the FX models use a similar adjustment like the Air Arms gun you have. The Monsoon doesn’t.
What I was getting at was that basically the Talon SS has no other tuning adjustment that comes factory with the gun. Only the spring adjustment. So with out getting into the air tank and changing the top hat or flow tube if I’m using the right terms. Or with out changing tanks to the different type valves that they have in them you are limited to what you can do to get a reasonable shot count and power curve with the tank that comes with the Talon SS. But at least that option is there to change tanks on the AirForce guns. You don’t have that option on the Air Arms gun unless there is aftermarket tanks like Lloyd is making.
The Monsoon has no adjustment. And if you search any info about them they depend on fill pressure to cycle the action depending on pellet weight. I’m not sure exactly how the pressure changes how the system works on the Monsoon but you have to lower the fill pressure the heavier the pellet you use. The bolt will not cycle if the fill pressure is to high. And then you have a given amount of shots with that fill pressure before the bolt will not cycle again because the air pressure is to low. So that controls your shot string.
The Air Arms gun you have I guess does not have any other adjustments like the Marauder does then. You can’t adjust the spring pressure or striker stroke then I suppose. If that’s true then I guess you are limited to the amount of tuning you can do. Kind of like the Monsoon. But you can at least adjust how much air you can allow to flow to the pellet that your striker releases from the air valve then. So you have more to work with than the Monsoon but not as much to work with as the Marauder if I’m seeing it correctly.
So hopefully Lloyd will get that Aluminum tube done for me and then I can see how it affects the way I can adjust my .25 cal. Marauder. I’m really excited about that. And can’t wait to start trying it out once I get it and get it installed.
GF1
I can live with the amount of “easy” tuning. Not inclined to do any more work than necessary. Just use the chrono and look at the strings to figure out how it is working.
I have seen some unexpected things so far. I am sure I will see more.
I will pretty well know the nature of the beast before I get it outside for some pellet testing at ranges suitable for my hunting purposes.
Still need to get a couple more kinds of pellets for when I get it outside.
twotalon
TT
At least you now have some good chrony data to use with your outside tests when you get to do them.