by Tom Gaylord, a.k.a. B.B. Pelletier
Today’s report comes from a question asked by blog reader Richard, who is perplexed by his Benjamin Marauder air rifle. He said he wondered what pressure he was supposed to fill his gun to, and then at what pressure he was supposed to stop shooting.
As the days passed after asking his question, Richard eventually figured it out on his own and now knows what to do, but today’s report is for all those who haven’t figured it out yet, as well as for those who have held off buying a precharged airgun because they feel there’s so much they don’t understand.
More power!
At the Roanoke airgun show last weekend, I talked to a shooter who claimed he pumped and pumped his old Sheridan until it cracked like a .22. Now, I know that’s impossible and I’ll tell you why.
Firearms and airguns are NOT alike!
People think that firearms and pneumatic airguns are alike. The more pressure inside them when they fire, the faster the bullet or pellet goes. That may be true for a firearm (within reason), but never for a pneumatic. You see, a pneumatic airgun has something that a firearm doesn’t have — a valve.
The pressure generated by exploding gunpowder gets directly behind the bullet and pushes it. More pressure equals higher velocity — within reason. There’s nothing in the way of the expanding gas to prevent it from pushing on the bullet.
In a pneumatic gun, however, there’s a valve. That valve has to open before any of the pressurized air can get behind the pellet. If the air pressure is too high for the valve to open, it doesn’t matter how much pressure there is — the pellet is going nowhere. That’s the difference between a firearm and a pneumatic airgun. So, pumping or pressurizing a pneumatic rifle beyond its design limit doesn’t increase the velocity — it slows it down and eventually stops it altogether.
Therefore, Richard was asking how he was supposed to know the max fill pressure of his gun so it would operate correctly. He wondered that because of conflicting information from Crosman, my blog and probably from other sources on the internet. The fact that the Marauder lets you adjust the maximum fill pressure just made this more confusing for him, and I can see why.
He asked me how he was supposed to figure out the max fill pressure and at what pressure he should stop shooting — the starting and ending fill pressures. There are several ways to find this out. The easiest way is to use a chronograph. To do this, you fill to a given pressure — say 3,000 psi — and start shooting through the chronograph. If the velocity of the pellets continues to rise as shots are fired, the valve isn’t opening all the way; and you know that 3,000 psi is too high for a starting fill pressure.
As you continue to shoot, the velocity will stabilize at some point. When it does, you know that the valve is now opening all the way on each shot. Of course, you will have shot several shots past this point before you recognize it, but usually it will be a very little pressure above what remains in the gun when you notice it. So, fill the reservoir again and watch the needle on your fill gauge. When it stops rising fast (if you’re using a scuba tank) and starts rising more slowly, you’ve opened the inlet valve of the gun’s reservoir and are now adding air to the reservoir. Add just a few hundred pounds of air by watching the gauge on your tank, then shut off the valve and note the pressure at which you stopped. Maybe it will be 2,600 psi. If the gun fires as fast as it did before, you know that the max fill pressure for your gun is at least 2,600 psi or maybe a bit more. Refine this by iterating the process.
The following graphic shows the relationship between pressure and velocity as I have described it here.
What if you don’t own a chronograph? This may be Richard’s dilemma. Is there any way he can figure out the max fill pressure and where to stop shooting?
Of course there is. Airgunners a hundred years ago didn’t have chronographs, yet they did fine by watching what their guns would do. If they wanted to know how powerful their guns were, they shot them at an anvil and looked at the lead splat. If they wanted to know when to stop shooting, they watched the guns and when stopped when they could see the bullets coming out of the barrel. They filled their guns until they couldn’t pump anymore, so max fill pressure was taken care of.
But Richard shoots a gun that’s much faster than a 100-year-old pneumatic. His pellets don’t make splats — they disintegrate! And he fills his rifle to a much higher pressure from either a scuba tank that gives him very little feedback or a triple-stage hand pump that doesn’t have much more feedback.
How does he know when to stop filling and when to refill the gun? Simple, he watches his target and sees where his pellets land.
Let’s take an example and have Richard fill to 3,000 psi, then shoot at a bullseye 35 yards away. If the pellets are climbing while he aims at the same aim point every time — making a vertical group, Richard knows the velocity isn’t stable. He doesn’t know what the numbers are — just that they aren’t stable.
Then, when the rifle starts grouping all the shots together, he knows the velocity has stabilized. Like before, by the time he notices this, he will have shot past the optimum starting fill pressure; but he can always fill to a few hundred psi more than the gun has in it at the point he notices, and eventually he’ll find the optimum fill pressure. The graphic below illustrates this.
Finding the stopping pressure is just the reverse of this. Shoot until the pellets start wandering on the target, again (usually dropping down, again, but sometimes just wandering to one side or the other). Then, you can start filling the gun, and the ending pressure will be a few hundred psi above where the gun begins to accept pressure. From now on, you’ll know approximately how many shots or magazines you can get from a fill; or, if there’s a gauge on your airgun, you’ll know when it’s dropped off the power curve.
You don’t know until you know. You know?
You can read about this all day long and never understand it. This is something you must experience firsthand — as in shoot a PCP and watch it happen. The first time you see it, you’ll understand…and forevermore you’ll wonder why others have so much trouble understanding how precharged airguns work.
When I was contemplating entering the world of pre-charged pneumatics (pcp’s) I was overwhelmed and therefor stymied for awhile by the amount of equipment necessary.
A pump or a tank, right hoses, gauges, adapters, chronograph, etc. I sat on the fence for awhile but finally bought a pump and fumbled around trying to find fill pressures and determine the power curve by shooting at 30 yards. You can do it but it takes a lot of time and effort.
The investment in a carbon fiber tank and pro chrono chronograph was well worth it to me since it opened the door to all pcp’s. Once you have a tank and chronograph it unlocks the secrets and makes filling all pcp’s a breeze.
Since my time is limited I’d rather be shooting for accuracy than pumping or shooting to determine fill pressure and power curve. The chronograph and carbon fiber tanks are the best money I’ve spent in airgunning. Took my affinity for shooting guns to a whole new level.
I stayed on the fence too long. Should have bought a tank and chronograph sooner.
Kevin
You need to slow down and enjoy shooting your air rifle more.
I’m with Kevin! It is not about “speeding up” the shooting process, but maximizing the enjoyment and value of the limited time we may have to shoot.
I got my Marauder and worked with just a Hill pump for many months. I did enjoy shooting that way, but once I got a CF tank it became much more enjoyable. Now if I have an hour or two to shoot, I shoot for most of that time rather than pumping for about a quarter of it.
I still use the hand pump to refill after limited sessions of one or two mags, but the option of the tank on hand really makes things better.
The Chrony I had from diagnosing problems with spring guns before, and I can’t really imagine being “serious” about working on and improving your own guns without one.
I agree that neither are really needed if you just want to have a gun to shoot, but if the guns themselves are the hobby, they really are needed. I think of it as kind of like a car: there is no problem using them as a tool for transportation and having no tools to work on them, but if the car itself becomes the hobby, you are probably going to want to have something more than just a bucket and sponge to enjoy it with!
Alan in MI
RidgeRunner,
“You need to slow down and enjoy shooting your air rifle more.”
Exactly what a carbon fiber tank and good chronograph enables me to do :-).
kevin
When I bought my first PCP I got the pump too, it seemed like the way to go and how hard could it be, it’s a bike pump on steroids.
Then I noticed I wasn’t shooting my PCP’s as much as I wanted to because I had to fill them up afterwards and I didn’t like pumping all that much… Then I got a carbon fiber tank, man are these things cool or what?!?
I was trying to get the best deal on tank and was trying to figure out how to get the good hoses the first time and for the smallest amount of money possible. That’s when Ninja came out with the small 90 cu/in tanks and hoses that PA sells as AirVenturi tank, 10$ to get it filled, a lot of fills for my guns these are THE way to go.
If you’re only using a Disco to get rid of pests in your yard once in a while and take only a few shots once or twice a week, you’ll do fine with a handpump, if you want to shoot, you want to have fun with your guns, GET THE TANK!
J-F
…and a chrony
J-F,
I would add that if you get a big bore you need a CF tank, too. Pumping for 5 minutes for just 2 or 3 shots gets old real fast!
B.B.
Amen !
Amen, Kevin. Hand pumping isn’t all that bad, but if tank fills aren’t a problem, go directly to a CF tank! I’m rationalizing a little bit here, but 1) the cost of a tank is approximately zero across the humongous amount of airgun shooting it enables, and 2) the cost of a tank is not that much more than a hand pump, and 3) a CF tank holds its resale value very well, if by some strange twist of fate you decide PCP shooting isn’t your thing.
And while a chronograph isn’t mandatory for enjoying your shooting, it sure does provide a *lot* of useful insights. Of course, I would count a chrony as mandatory if you ever fancy an adventure like, say, going within ten feet of your Marauder’s various adjustments! I also endorse the ProChrono Digital. I sprung for the computer connectivity kit and software, which enables you to download long PCP shot strings into, say, an excel chart. I think it’s Windows-only, though.
-Jan
If you want to try slow, you need to take up blackpowder. I got a good look at it from the obnoxious guy next to me at the shooting range. Between loading and fussing around, it literally took him 20 minutes between shots. It didn’t bother him at all. He was talking up a storm and having a good time with his friends in the interim. It was also interesting to me to see the gun in action, especially the way the flint sparked. I would be nervous about having sparks so close to my eyes, but this didn’t seem to bother the guy and his friends who followed nature’s way without eye protection.
Matt61
Great blog BB.
Before I got my chrony the above is exactly what I done.
Watch where your pellet hits and keep track of your pressure. And write it down. Then you can go back and compare.
Also forgot.
The 12 gram CO2 cartridge guns will teach you about pellet drop verses pressure left in the cartridge.
They are even good (CO2 guns with the 12 gram cartridges) to practice hold over of your scope as the cartridge gets empty.
I guess I am going to have to break down and get a chrony sometime. I was glad I borrowed one when I got that Talon SS from Mac. It took about forty shots before I reached the top of the curve. I started at 3000 PSI and when I reached the peak my pressure was only 1800 PSI. Of course this one is sort of a hybrid, but I like that low pressure.
Hi B.B. You commented on the bloke who could pump and pump his old Sheridan and make it crack like a .22, and with the valve it has is limited by the hammer spring as to how much air is released (along with valve spring and transfer port diameter to some degree). However I’m very fond of the Sharp Innova and Ace which have exhaust valves, they just dump all the air in the valve as soon as the sear moves. My Innova though not quite as loud as a .22 came pretty close at times, but then there is a lot of plastic on those and i thought it prudent not to push it past it’s limits.
I recently fixed up an old Chinese SMK B45-3 which is a 12 shot repeater multi pump in .177, a lot more metal on that one and it has an exhaust valve. Though i have to admit that it’s no where near as loud as i could get the Innova, but its surprisingly accurate and fun to mess around with.
TTFN
Best wishes, Sir Nigel Tetlington-Smythe
Sir Nigel,
Yes, the blow-off valves are different. Of course they have their own set of limitations, such as the trigger getting harder as the pressure rises. But you can put a lot more air into one of them.
Maybe I should do a blog sometime?
B.B.
“Crack like a .22”. Yeah….. Amazing what a lot of imagination , acoustics, and a failure to make a direct comparison under the same conditions can do to boost your ego.
twotalon
Hi B.B,
I’m a day late with this comment, but anyway….
Thanks for your coverage of the Roanoke show! This was the first time I’ve missed it in about 6 years or so, and I really appreciate seeing what I missed.
Like several other readers, I am anxious to hear more about your BSA Meteor. I grew up shooting airguns as a child and teenager, but then set the shooting sports aside for many years. What re-ignited my interest was when I inherited my grandfather’s old air rifle: a BSA Meteor Mark 4. I bought a new breech seal for it and a replacement rear sight (those are notoriously fragile), and promptly had a blast with it. One thing led to another, and soon I had a pair of Weihrauch springers and was restoring old CO2 pistols as well….
I don’t know the age of your Meteor, but mine was made in the mid-1970’s. It has a “loose” breech and barrel compared to the Weihrauchs, and shoots best with large-diameter pellets. I found after much experimentation that mine really likes the old (discontinued) Beeman Bearcubs, so a few years ago I found a online retailer that still had some and bought them out. Although it is nowhere near as refined as my German rifles (the trigger is a bit stiff and the rifle is very buzzy), the Meteor is still a lot of fun to shoot. Mine makes ~9.2 ft-lbs and is quite accurate at 20-30 yards. I have even shot aluminum cans at 60+ yards, but the trajectory gets very loopy at that range.
Thanks again for your great blog!
Neil in VA
Neil,
Well, you just made it official. Of the 3 vintage guns I got at the show, the Meteor ranks as number 1 in interest, with the Falke falling to a distant number 2. The Diana 25 has had no interest at all, which makes it number 3 by default.
I will review them in that order.
Kevin said he thinks I may have a Mark III from the picture, but it’s had to say for sure. I have made no attempt to discover what it is, because we will all do that together.
Thanks for the advice on the pellets. I will keep it in mind as I test the gun.
B.B.
BB
What kind of finish should the metal have in the compression chamber? Should it be mirror smooth if possible?
RR,
Not mirror smooth. It should look like an automobile piston sleeve, with a light crosshatch pattern to hold the lubricant.
And that rifle doesn’t need silicone oil, though it isn’t bad for it. Plain old 3 in 1 is fine. That’s a low compression gun.
B.B.
B.B.
I have a large quantity of silicone oil so I am using it to soak the seal in. I am thinking of using moly grease on the piston side of the tube or should I use something else?
RR,
Moly is fine, as well as lithium.
B.B.
I don’t know if anybody has tryed these. But a brake cylinder 3 finger hone (like when you rebuild a wheel brake cylinder for drum brakes) they work great.
I have a old one that you can replace the honing stones and it has about a 12″ reach of depth. Works great for smaller bores like air chambers on air guns.
A bit of “off to the side ” about sound…
I was thinking yesterday about an experiment involving sound. My T200 sounds different with or without the thing on the end of the barrel. I will not call it a “brake” because it does not function as such.
I want to check out the difference in sound from in front, to the side, and behind the muzzle from the same distance with and without the “thing” installed. I have decided on using the video cam and shooting in a wide open flat area to minimize reflected sound.
It will take some experimenting to figure out how far away to set up the camera and what microphone mode to use. I don’t want the automatic recording level to hide the differences. It will also have to be a quiet time of day to keep background noises from playing with the audio.
Anyone interested ? If so, it will require more editing to keep the footage as short and clean as possible. Then I will have to hope that file conversions and such will not louse it up.
twotalon
I love it!
Silencers and shrouded barrels are illegal here so we’ve talking about sound redirection and been wondering how well it could work. This could offer some insight.
J-F
J-F
An interesting thing that has me wondering is that the report sounds louder and sharper WITH the thing installed. Has to something with how the sound is focused.
twotalon
TT
I haven’t tryed using a recorder but I have done it by standing in different places with my buddy shooting the gun. Makes a difference were your at in relation to where the gun gets fired from.
I would be interested in the results if you did the experiment.
GF1
I will do it. Got 2 votes already.
Recorders are tricky. Does not make any difference if they are the little pocket memo things, tape recorders, or video cams. Probably the cell phone cams and cam/airgun-video cams (like my Nikon D 3100) too.
They have automatic recording levels. You have some different modes on some, but you usually have to get far enough away that the audio does not easily max out .. or you will hear about the same loudness, but maybe a bit different quality of sound.
Went out a bit earlier to try to figure out modes and distance, but had too much wind noise in the mic and combine noise in the distance. Was sprinkling too.
Must figure the whole thing out, then run the test. I want to edit six clips together in less than the length of time that it takes to shoot once then reload once. The visual reference should be self explanatory .
twotalon
Great blog B.B. PCPs have so many more variables than springers that the intimidation and confusion for a newcomer seems inevitable. Especially for a gun like the M-rod where you not only have to deal with the reservoir pressure changing, but then you can also adjust the hammer spring force, hammer stroke, and transfer port cross section. And … you can use different weight pellets. With all those adjustments it isn’t too hard to get the gun where you wonder what is wrong with your M-rod. Oh, and you can foul up the trigger adjustment too. Been there plenty, LOL.
Because I like to work on guns more than shoot them, I use a chrony all the time. It is a valuable tool, and for a gun like the M-rod, I see it almost as a necessity. But watching the pellet migration on the target is a fair substitute. The chrony should be on the short list of PCP accessories, and I think most serious PCP shooters eventually end up with one.
I wonder if anybody with more than one PCP doesn’t have a chrony?
Lloyd-ss
Lloyd,
I bought my first Chrony used at an airgun show, and I resented having to pay money for something that wasn’t either a gun or pellets. Then I used it for a short time and saw what I’d been missing.
When I decided to write the book about the Beeman R1, I knew I needed the best chronograph money could buy, which is when I bought an Oehler model 35P. Since then I have been an evangelist for chronographs. I do remember my life before them, but it just accents the need to have one when fooling around with airguns.
B.B.
Well, your evangelism worked! I needed the hard data, and you can’t get that without a chrony.
My first Chrony was less expensive than most of my airguns and came with a replacement discount for broken or, ahem, shot up, chronys. I have used that discount twice. That is probably why I don’t invest in an expensive chrony, LOL.
Lloyd-ss
The other “need” for a chronograph for airguns isn’t being talked about.
If you want to sell or trade and airgun you need chronograph numbers today. Without accurate numbers many potential buyers are suspicious about the health of your airgun and expect problems which translates into a wholesale price usually.
kevin
Kevin,
That was the case at a number of dealers’ tables at Roanoke, and I saw that it made a difference. When a gun shoots 150 f.p.s. too slow you know it needs something.
B.B.
Thanks for another interesting read.
I now have two more Blog Topic requests for you:
1. (Maybe you’ve done it already?) Chronograph recommendations. (No, I’m not spending nearly $600 for the Model 35P.)(I’ve been following “The Thousand Dollar Thousand Yard Shot” series and that’s my next project. I think it’s on the MAC Channel on YouTube. Add-in: I found a YouTube comparison of the Model 35P vs. whatever the F1 is. The guy says that if you’re just interested in Velocity, it’s a fine chrony (F1). Any comments about that?)
2. BASS: Breakbarrel Air Suspension System (I really wanted to skip the “B” in the acronym after my rifle (not the M-Rod) started shooting wildly.) I’ll bet you already know exactly how this system would be implemented. (Hint: I think I’m going to put some planter hooks above my shooting stance, spaced slightly less than the gun is long.) I’m hoping this system will be a reliable way to take the shooter out of the equation, since you can’t shoot one out of a rest or on a sandbag.
I’ve integrated pumping the Marauder into my exercise routine. A bulk tank system would be nice (but see 1 above). My wife is already threatening divorce… something along the lines of “The firearms weren’t enough! Now you’re bring all of these toys into the house!” My reply: “They are not toys. I’ll bet California is going to reclassify them all as Assault Weapons soon.” (Seriously, several online vendors WILL NOT ship guns/ammo/pellets/etc to me because they are concerned about being sued by our anti-gun state DA.)
Richard,
/blog/2013/03/how-chronographs-changed-airgunning-and-not-always-for-the-best/
The above is a blog B.B. did about chronographs. Hope it helps.
Edith
lloyd
When I got my first Disco I didn’t have a chrony (all though it would of been nice to have). I use the chrony on my CO2 12gram cartridge guns and my pump guns also (1377 and 2240). Then when I got my Marauders I knew I needed a chrony to accomplish getting them to shoot like I wanted.
I now have air tanks, a Hill pump and a Shoe Box compressor. Oh and of course (I will say it again) the chrony.
Airgunning = bottomless money pit. (But good, clean fun !)
Lloyd-ss
So many interesting things to learn involving air guns.
But yep fun stuff.
I never liked PCP rifles until I went hunting with my break barrel at high altitude it just turned out to be a very heavy walking club. I have learned my lesson now and invested in PCPs still don’t like the lack of recoil just don’t get the feeling of satisfaction when huntiing with them like guns wit recoil but high altitude and cold conditions PcPs every thing else I use break barrels. In Trinidad the cheapest PCP goes for $11000 while the high end break barrel is $8000 compared with a high end PCP for $20000 up. Got an import licence and imported my own it was not even close to the prices of the dealers saved up to 50% that way. On today topic I being still blessed with youth so I can walk with a buddy bottle in the field where I can tinker with different pressures in actual hunting conditions which allows the rifle to perform at its fullest potential. I would say PCPs are the most diverse of all airguns But it all depends on what the shoot is looking for. I have seen a boastful person of a Fx got out shot with gamo 1250 hunter customising does make a good marksman.
If you want recoil, you may need to move up to large bore… A Rogue, perhaps…
Remember Newton… The momentum of the projectile is matched by the opposite momentum of the rifle. A 10-20gr pellet is nothing against the 8-10lbs of the rifle (7000gr per pound, as I recall — so 20gr vs 70000gr is imperceptible. But something around 100gr starts to give some push)
And not only is overpressure fighting the valve, but isn’t it positively destructive in wearing out your seals? I am very alive to the possibility of damaging seals after my experience with the Daisy 747. On this subject, something very weird happened with it the other night. In the midst of flawless functioning, I opened the cocking lever and found myself unable to close it because of great resistance. I cautiously retried and experimented but felt the same pressure. I remembered the cardinal rule about never forcing something, but with the lever extended, I couldn’t imagine how to get it in a box to send to Derrick. So, in a moment of desperation, I did force it. There was a loud pop, and the lever closed. I wondered if I had popped a seal, but the pistol continued to function flawlessly afterwards. I still have to follow up with Derrick about that. Whatever it was did not cause the fist sized 10 shots groups that I subsequently shot at 5 yards with the pistol. The groups were all one contiguous hole, just big. Who would have thought the Daisy 747 was so destructive?
Titus, thank you for your kind comments. I didn’t realize that I completely missed yesterday’s blog. Work had me going hard from morning ’til night, and I just spaced it. Yes, you’re right. My book is called The New University Library, and is pretty much like the title says. Do not look for it next to Jack Reacher novels at your local drugstore. It is put out by the American Library Association (ALA). And I found out yesterday that it will be quoted in some ALA report. That means that I will occupy some small corner of some document or website that is visited by 20,000 people a year! Thus one starts on the road to becoming a legend in one’s own mind. Well, my goal was not to be as boring as most of the library literature, and I think I succeeded in that although it is not saying much. The fact is that writing the book felt like nothing so much as writing on the blog, so I have put my training to use. As it turns out, some of that book had to do with the dynamics of communication in the information age, something that we do. I’ll have more to say about my discoveries in the fullness of time… You’re way ahead of me with this let-off business. Are these wheels you mention for a compound bow? It’s nice to know that with my 60 pound bow I’m operating in the power range for such long-distance shooting. My original hope was to experience the faint echo of the 180 lb. bows used by the English archers and to work up to the 60 pound weight. But I’m starting to wonder. When, approaching full-draw, there is a demonic shrieking in the muscles, and I just release. I don’t know when I will get time to build up the specialized muscles.
Does anyone have difficulty with the height of benchrest tables at their shooting range? You can position your sandbags all you want and get your specialized shooting rest. But if the table and/or chair is the wrong height or the table is cut a particular way, you will be out of position, and all that goes for naught. I’m like a pretzel on the benches of my shooting range; natural point of aim is out the window. That I’m able to shoot any kind of groups is somewhat surprising.
Matt61
Matt61
I’m enjoying a beautiful fall day up here in British Columbia. After 3 hot months of summer, it is good to be able to enjoy the cool (20 deg. Celsius) afternoon getting the garden harvested, and ready for next years crop of food. As much as I enjoy shooting airguns, they take 2nd seat when it comes to gardening. Because of the many market gardens close by, people have told me I’m wasting my time growing my own. I just don’t see it as a wast of time. Gardening has always been a passion for me. To me, there is nothing better then fresh vegetables in a salad, or a cool cucumber fresh picked on a hot summer day. Not to mention the tomatoes I will be using this winter for pasta, or chili. When I read about the amount of chemicals used in processing store bought goods, I feel I have done the best I can for my family.
I just took for granted you were talking about a compound bow. My long bow is my heaviest weight at 50lbs. It is one of 12 made by Check-Mate Bows, located about 30 miles east of Vancouver. I used it in novelty competitions, such as the clout shoot. To shoot clout, you try to aim at a flag, or the clout, that is placed on the ground at a distance of 165 meters ( 180 yd.). It is difficult trying to aim when your bow is elevated 45 deg. to the horizon. Circles made with string, are placed on the ground every 36 in. from the flag. You get 5 points for the flag, or clout, and then 4,3,2,1. The clout was always a favorite shoot for me. Some people take the clout extremely seriously, and would practise all year for it. I could never find the room to set up a clout. The one re-curve I have left, is made by Les Howis of England. It is a beautiful, all wood, 68″ take-down, with 38 lb limbs. An extremely smooth target bow, right through to my 29 1/2” draw. The most powerful re-curve I owned, was a target take-down bow made by Yamaha. Yamaha was one of the first makers to use carbon fortified limbs. It was 68 in long and had 42 lb. limbs. I don’t think Yamaha is making target bows these days, however, they competed well with bows made by the American giant, Hoyt. The amazing Rick McKinney, from Arizona state, used Yamaha exclusively. Rick McKinney and Daryl Pace were the two dominant archers in the days I was competing. Daryl won the 1976 Olympics in Montreal, when he was 16yrs. old. An incredible achievement that I remember well, happened in Japan. Rick and Daryl were invited to a friendly competition by the Japanese archers. They shot 2 FITA rounds over two days. After the first day, Rick had ended with a 1332, out of 1440 points. That would have been amazing, however, Daryl finished with 1345. To understand why these achievements are amazing, you must realize the distances involved are 90-70-50-30 meters, and 36 arrows shot at each distance. They scored a majority of 10’s, and nothing less then a 9 at each distance. I met both archers at an indoor tournament in Las Vegas. Both were humble, and always ready to help others.
I would love to read your book, however, if I am unable to obtain it locally or through Amazon, etc., I must find another method. I have started writing a book a number of times, but have never got too far. I can admire your achievement on finishing what you started.
Ciao Titus
Titus Groan
Talking about gardening. It was almost like I was hearing my dad talk. He loved his farm and garden.
Then the guitar making and music playing. Then guns.
Is there a possibility the piston adjustment backed out some?
With the cocking level fully open you would see 1) the oil-pad, and 2) the <> wedges for adjustment. I believe the proper setting is something like a 1/2″ gap on the lever to receiver distance. A screwdriver allows you to rotate the piston — lengthening or shortening the piston rod. Too long and the piston will bottom out with too much gap on the lever to “over-center” (the snap-closed position). Too short and the lever won’t “lock” closed.
I started with pcp guns by buying a Discovery. It was a good gun. I still have it but it’s definitely not the same gun it was when I got it. Things broke on it so I ended up replacing them with better parts. Eventually I decided I wanted more out of it and decided to try and see exactly what I could get out of it. So I started putting in bigger valves, power adjusters, tuned heavy springs to help regulate air usege more efficiently. That eliminated hammer bounce since the springs are stiffer so the valve opens and closes without bouncing. Eventually my goal was to make my disco do everything a marauder does. I succeeded but the insides of the gun are no longer a disco. Everything from the air valve back is all custom stuff. PCP guns are fun. Don’t let the high pressure scare you or confuse you. Think of the air tank like a gas tank in your car and the air valve like the engine. You have 24 inches to accelerate that car as fast as you can. That’s the barrel. Overfilling the gas tank will not make the car go any faster, but putting a bigger engine in the car will.
Some how cars always get thrown in with our air guns don’t they. 😉
As far as pcp guns go they work so well when trying to explain how the gun works. If you think about it not everybody understands how a pcp gun works, but everybody understands how a car works. In how they work both function similar but the result is a bit different. For example, you wouldn’t get your car moving as fast as you could to hit a concrete wall…..unless you were a muslim that was promised 72 virgins if you did that….but that’s not the point.
Well… Walking to the range is pretty much out… <G>