Archive for April 2008
Introduction by B.B. Pelletier
Here’s another guest blogger. BG_Farmer customizes a QB36-2 for us. He admits to not being an experienced airgun tinkerer, so this will provide some encouragement to those who’ve been waiting for a beginner’s project.
If you would like to write a post for this blog, please email me at email@example.com.
Bloggers must be proficient in the simple html that Blogger software uses, know how to take clear photos and size them for the internet (if their post requires them) and they must use proper English. We will edit each submission, but we won’t work on any submission that contains gross misspellings and/or grammatical errors.
From Clunk to Thunk: A Beginner Customizes a Chinese QB36-2
After just a couple months of airgunning, I dedicated my Hammerli 490 to 10m targets and 20m plinking with open sights, as it’s too much fun to mess up with a scope. However, I wanted to keep up my skills with scopes for firearms, as that was one of my initial justifications for getting an airgun.
I decided to get another air rifle to dedicate to long-range targets and silhouette shooting with a scope. Since we have a breakbarrel and a sidelever (my wife’s QB88), it seemed that an underlever would be best, especially considering the scope requirement.
At my level of the sport and cheapness, however, a TX200 or HW97 seemed silly. That kind of money would go to a 10m gun or PCP, so I ended up with a QB36-2 (generic industry base for Tech Force 99) for a low price, with the hope I could improve and fix it if necessary and learn something in the process. I wasn’t disappointed.
Canted action, massive stock – my work was cut out for me
Out of the box, the gun was pretty much as BB described it in his Tech Force 99 blog, except that the entire action was mounted at an angle due to an improperly drilled rear action screw (behind the trigger group), resulting in a cant.
It was easy to fix the cant with a drill and tap, but the huge stock and excessive length of pull just didn’t fit me, so I whittled down the tight-grained, beech-like wood (acacia?) substantially with 50-grit sandpaper and some saw and chisel work. I removed all but what was necessary of the cheekrest.
I recontoured the forearm since the original design looked racy but resulted in thin, fragile wood at the front. The pistol grip was reduced from chunky to merely substantial. I block-sanded up to 220 grit (at least as thoroughly as the factory) before using a water-based walnut stain and 3 coats of oil-based semi-gloss polyurethane with a scrub-pad finish (to cut the sheen a bit). The finishes were chosen mainly because I’ve used them before and had the materials on hand. My goals were function and fit beyond all else, although I may try my hand at making it fancier or even adding checkering later.
Accuracy testing…and more problems
After the stock work, I was pretty happy with the rifle, as it fit me and was shooting accurately and powerfully. Accuracy at 20 yards was approaching .50″ with little effort using Crosman Copperhead Competition Wadcutters. You can see why I liked it despite its problems. As far as power, it penetrated both sides of a steel, water-filled can at 20 yards with the same pellets. With open sights, I consistently hit targets at 50 yards and a coffee can at 75 yards.
I added a scope, according to my original plan. I originally selected a 4×32, but it broke within 50 shots. A 3-9x32AO went on next. It held up but wouldn’t stay in place after several hundred break-in shots. The scope stop bent like a potato chip. The rifle also started to shoot erratically, which I blamed on the scope-shift at that time, although now I don’t think that was the main problem.
One day, the rifle wouldn’t cock, so I shook it vigorously and whacked it gently against a post, whereupon a coil of spring fell out. The rifle actually cocked better and shot smoother afterwards, despite the occasional piece of spring jamming the action. However, I knew I needed to fix it before it could be used seriously.
Having spent a good deal of time redoing the stock, I decided to see if I could also improve the firing cycle rather than simply replace the broken spring, so I ordered an aftermarket spring (Jim Maccari’s e3650) and synthetic seal (Maccari’s Apex) along with some of Jim’s heavy tar.
The spring was broken in several places, with the longest piece being roughly 8″ long. The leather seal was torn (probably at time of manufacture by the rough cocking shoe cutout) and dry, despite having lubricated it as much as I dared. It’s amazing that the gun shot at all. I think the torn seal allowed enough energy to come up from the spring to put out pretty good (but inconsistent) power via dieseling.
The piston is fabricated out of rolled steel and had some pretty rough welds on it. Remarkably, the finish inside the cylinder was smooth (except for the cocking shoe cutout). I’m no tuner, but it seemed pretty obvious what had to be done in terms of polishing and lubricating. After degreasing with acetone (I’m not recommending it; it’s just what I used), all contact surfaces and rough welds were smoothed down to 220-grit smoothness. Sounds coarse, but it did the job. It was certainly much smoother than the factory finish on the interior metal, even after several hundred shots of break-in.
My goal was not to equal the original factory specification of 900 fps or the 1100 fps claims some make for this rifle. I just wanted to make it smoother and more consistent, with just enough velocity (gauged by use) to shoot well to 50 yards with the proper pellets.
I spaced the preset spring in the piston until there was a little preload on it when pushing in the end cap. It’s still a hand operation. WARNING: Use a spring compressor. I knew my spring was broken, so there was very little tension on it, but I should have been more careful and used a compressor anyway. The stock spring on a QB36-2 is monstrously long, so it has a huge amount of preload (compression when uncocked).
The difference in stack height (compressed length) between the old and new springs was approximately 1.8″, but I spaced the new spring about 1.25″ inside the piston, using washers to take up the space. When I ran out of washers, I used pennies sandwiched between washers.
Due to the position of the piston latch, there was very little (if any) room for spacing at the base of the guide. I was afraid that making the piston heavier would degrade the firing cycle. In the end, I think the extra weight in the piston may have actually improved the firing cycle, working in concert with the somewhat softer spring to stabilize the piston’s velocity.
Sealing the deal
The synthetic seal got a custom (shade-tree engineered) mounting, made with a plastic conical washer to fit inside the seal. The new seal also required spacing (fender washers) on top of the piston, since it was thinner than the factory one. The design depends on the seal thickness, as the seal and piston are pushed back by the sliding cylinder. I added a drop of silicone oil on the edge of the seal before inserting it in the cylinder.
On the forums, I’ve seen many nice lathe-turned seal conversions, and was afraid mine would explode on the first firing, but it’s held for about 300 shots with no sign of degradation. Maybe the blue thread locker I used on the (original) screw secured the seal. If it breaks, I’ll make something better. Meanwhile, it works.
Tarred & molyed
After polishing parts and assembling the piston and seal, the cylinder and main tube got very spare amounts of Beeman M2M Moly Paste rubbed in, while the spring got a very light coat of Maccari’s heavy tar on the outside and on the plastic spring guide, as well as a little bit of M2M moly on the ends.
The trigger was light enough for me, so I didn’t do anything fancy other than make sure it had no burrs. I also added a little M2M moly. If I were to do it over again, I’d do even less to the trigger and dispense with the moly, since the trigger is now almost lighter than I like it. Variations are almost a certainty, however, with these guns.
How it all turned out
Putting the rifle back together, I didn’t have high expectations, given my level of knowledge (none) and mechanical ability (little), but it did cock and fire. Actually, it cocks very smoothly and lighter than before, with the cocking effort roughly in the high 20s, whereas it was in the mid-30s when new. The firing cycle is now amazingly smooth, just a little harder/rougher than my Hammerli 490 (which is not a harsh shooter at all). Of course, the power is higher, too.
There was no dieseling, even on the first shot, and no vibration to speak of, although I could have been just a little more generous with the heavy tar. The power is probably slightly reduced from stock, but nowhere near as much as I would have thought. It still puts a Copperhead wadcutter through both sides of a water-filled, steel can with a nice plume of water for effect, and 75-yard shots at coffee cans with RWS Superdomes are possible.
The weight of the gun and its muzzle-heaviness have now become an asset. With the new spring and seal, the rifle doesn’t move when fired, so it’s excellent for offhand (which is good, because that’s the way I shoot). I believe the original spring with its significant preload might have been too much for the stroke, not to mention obviously brittle or otherwise deficient. I was amazed at the obvious differences in quality between the stock spring and seal and the Maccari replacements. I shouldn’t have to say it, but I will anyway…the Maccari parts were of much higher quality than the Shanghai originals.
Soon, I’ll remount the scope. I expect it to stay on better, although I still need to deal with a bit of barrel droop. Accuracy is consistent now with RWS Superdomes and Crosman pointed pellets, so I’m hopeful that the rifle is going to work out for my application. Ironically, while continuing to shoot the 490 and debugging this one with open sights, I’ve found that I’m getting good enough with open sights again (even at decent ranges), that I would consider getting rid of scopes. Almost daily practice with airguns is better training than what I formerly thought was frequent shooting.
by B.B. Pelletier
This thumbhole HW 35 is a rare version of the popular rifle.
The Weihrauch HW35 holds the record as the spring air rifle with the longest continuous production. Started in 1951 and never out of production through the present time, the 35 has seen hundreds of other classics come and go. When it was launched, the 35 was the first air rifle to have the famous Rekord trigger, which must have looked pretty spectacular back then. It’s still the gold standard for sporting triggers, but a half century ago there was nothing even remotely like it.
Rekord trigger shown here in the cocked state has ruled the airgun world for over a half-century.
The HW35 has always been described as a big airgun. In its heyday, it reached velocities in the mid-700s in .177 caliber, which was as fast as a spring gun could shoot. The leather piston seal it originally had was no drawback to speed, but when the velocity races began near the end of the 1970s and Weihrauch switched to synthetic seals, the 35′s major shortcoming became glaringly obvious. It had a huge piston that was, unfortunately, short-stroked. More on that in a bit.
When the 35 came to market, airgun designers were not sure that the breeches of breakbarrel rifles remained sufficiently closed during firing, so a number of models had positive breech locks. The HW35′s lock extends from the left side of the base block, where the left thumb can hook it during cocking. It really doesn’t take much longer to cock this rifle, so the lock remained on the rifle. Breech locks are not common today, now that breech locking detents are more trusted, but the lock on the 35 is a pleasant reminder of the age of the design.
To open the breech, pull the latch forward first.
When the 35 was launched, scopes were uncommon for sporting airguns, so a fine open sighting system was installed. The front is a globe with interchangeable inserts, and the rear is a click-adjustable open notch. At the extreme rear of the rifle, an 11mm dovetail and two vertical holes were not for scope mounts but for Weihrauch’s diopter target sight. There were no formal airgun target matches in those days, but they were coming, and rifles like the HW35 were perceived to be suitable for target use, as well.
Globe front sight comes with many replacement inserts.
Articulated cocking link
In those days, all spring rifles vibrated, so anything that could lessen the buzz was considered. The HW35 had an articulated cocking link that allowed the cocking slot in the firearm to be very short, and the belief was that a solid forearm helped dampen the vibration. Whether it did or not is open for debate, but it provided a good place for a front sling swivel.
The Diana 45 (top) has a one-piece cocking link, while the HW35 below has a two-piece articulated link. The steel bridge holds the link close to the spring cylinder.
The Diana 45 (top) forearm needs a long slot for the link to clear while cocking. The HW35 (bottom) has a much shorter slot.
It couldn’t keep up
The 35 is a large air rifle, which led a lot of people to think it should also be a powerful one. When first launched, it was among the most powerful spring guns, but when the velocity races began in the late 1970s, the 35 just couldn’t keep up. It became obvious that although it had the largest piston on the market, the stroke was too short, robbing the gun of a lot of potential. Some 35s could make 800 f.p.s. with proper tuning, but that was as far as they went.
When the R1/HW80 was developed in 1982, it used the same diameter piston but had a much longer piston stroke. The result was the fastest spring rifle in the world for a little while. That dramatically demonstrated how much a piston’s stroke affects power.
Because of the length of the production run, the HW35 has been made in dozens of different styles. The thumbhole stock shown here is uncommon, as are all of the walnut-stocked rifles. The EL 54 is a special HW35 variant that has an ether-injection device on the side of the compression tube. It uses controlled detonations to shoot heavy pellets or round balls up to 1,000 f.p.s. It is the most valuable of all the HW35s.
Not gone, but forgotten
As mentioned earlier, the HW35 is still in production today. Beeman stopped importing it many years ago. Since they’re the exclusive U.S. importer of Weihrauch, the model is no longer available to us. No doubt, Beeman believed that Americans want only the most powerful air rifles, which is correct. If they tried to reintroduce the 35 here in the U.S., the high price and mediocre velocity would spell disaster. Fortunately, there are still plenty of nice used 35s available, and they aren’t commanding a lot of money. Just make sure you buy one for the right reasons, because nobody can turn it into a powerhouse.
by B.B. Pelletier
Pyramyd Air will have a booth in the exibit hall at the NRA Annual Meetings in Louisville, Kentucky, May 16-18 at the Kentucky Exposition Center. Admission is free to NRA members. Be sure to stop by the booth and say, “Hi,” if you’re at the show.
Also, the Little Rock Airgun Expo will be held this Friday and Saturday at the Saline County Fairgrounds in Benton Arkansas. Visit their website for all the information.
The first thing you’ll notice about the SIG Sauer SP 2022 BB pistol is that the sample I’m testing does not have the white letters shown in the photo on Pyramyd Air’s website. It is made by KWC, a well-known airsoft manufacturer that’s now making conventional airguns, as well.
This pistol is mostly polymer – something many shooters will want to know. With firearms being made from similar material these days, it isn’t that much of a stretch for air pistols to be made of the same material. Of course, the critical operating parts are metal, so the longevity is there just the same. And, the SIG Sauer SP2022 is in good company with other air pistols in its price range.
The controls are partly operational and partly for show. The magazine release on the left side of the grip does work and the mag drops free, just as it should. The safety is also on the left side of the grip and can be applied by the firing hand. That makes this pistol one designed for right-handed shooters, though I tried it in my left hand and found that both the mag release and the safety can be operated by that hand as well.
The hammer does move and is under spring tension, but it doesn’t move when the trigger is pulled. It can’t be cocked by hand because there’s no sear to hold it in position. The slide release is a separate part of the gun but it has no function. The slide is also separate but non-functional. When the gun is fired an internal striker does the shooting; the hammer doesn’t move and the slide remains stationary.
The box includes a small packet of BBs that appear to be of extremely high quality and uniformity. The surface finish is beyond any BB I’ve ever seen, and the diameter ranges between 0.1729″ and 0.173″. That’s one ten-thousandth of an inch of variation, which is ten times better than a BB. They look more like ball bearings than actual BBs, but I’ll wait until I shoot the gun to tell you if it makes any difference.
The forward underside of the frame has a short Picatinny rail, so you can mount aftermarket lasers and tactical flashlights with no problem. Pick something short, like Leapers deluxe tactical laser perhaps. Just pick something that doesn’t have to conform to a specific shape of the triggerguard – something that’s not model-specific.
The instruction manual is very much like an airsoft gun manual – lots of pictures with few words. It fits on one side of a single 8.5″x11″ sheet of paper. Both outside covers contain standard warnings, and everything is written in proper English.
The sights appear to be adjustable for windage by sliding them in their dovetails…until you look closer. They’re molded in one piece and the dovetails, while appearing very realistic, are not. The front has a single large white dot set into a conventional square post. The rear is a wide square notch.
The pistol is double-action only, with a light, smooth trigger-pull. It breaks at 6 lbs., 10 ozs with no noticeable creep. You should be able to fire the 23 BBs from the magazine very fast.
The BBs load in a single stack in the front of the aluminum magazine. A 12-gram CO2 cartridge is housed in the rear, where it’s entirely out of sight. KWC has recessed the cap that covers the CO2 cartridge so, from the side, the pistol’s profile is clean. That’s a feature air pistol shooters are very sensitive to, so this was a good move. To open the cap and change CO2 cartridges, you the large 1/4″ Allen wrench that comes with the gun. The cap is molded plastic, but the large size of the Allen wrench socket means very little strain is put on it when tightening to pierce the cartridge.
Remember to put Crosman Pellgunoil on the tip of each new CO2 cartridge you pierce. An alternative way to do it is to turn the gun so the magazine hole points straight up, then just drop the Pellgunoil straight down inside. That’s what I did, and the gun sealed quickly after piercing.
The advertised velocity is 330 f.p.s., so I will also be counting the number of good shots I get with a cartridge. I’m guessing at least 70 or so, which would be three magazines of BBs. The BBs are loaded one at a time through the same hole they’re shot from, while your other hand holds down the spring-loaded follower. It takes quite a while to load them all, and the irony is that you’re probably going to dump them in less than 20 seconds. The BB count of 23 is right on the money, so no confusion about how many this gun holds.
Well, that’s it for now. No good/bad assessments yet, but a hunch tells me KWC wouldn’t make a gun that wasn’t good. At least, that’s been my experience with their airsoft guns.
by B.B. Pelletier
Pyramyd Air will have a booth at the NRA show in Louisville, Kentucky, from May 15-17. They’ll be selling guns! This is an opportunity for you to see the guns before you buy them and save on shipping at the same time.
Now, on to today’s post.
I was going to start a report on the SIG Sauer BB pistol today, but that will wait until Monday. BG_Farmer posted a comment about how difficult handguns are for him, so today I want to tell you a story about how I took an anti-gun person and converted him into a 10-meter pistol shooter.
I was serving in Germany in 1976 when my first wife’s parents came for a visit. I was scheduled to go to tank gunnery for a month, so I missed most of their visit, but they really didn’t come to see me. We lived in an apartment on the American Kaserne (Ferris Barracks) in Erlangen.
Our front door was sheathed in steel, so I hung a pellet trap on it and used it as a backstop. In all the time I shot at that door, I never missed the pellet trap. If I had, the steel door would have stopped the pellet perfectly. The only gun I shot was a Diana model 10 target pistol. Because there was very limited space in the apartment, the longest distance I could get was 19 feet, so I used 10-meter rifle targets instead of pistol targets. They have a bull that measures 1.211″ across. The scale wasn’t perfect, but it was close enough for me.
Diana model 10 was a top-of-the-line target pistol in 1976.
Ten-meter air rifle target has a smaller bull than the pistol target. It’s more suitable for close-range target practice.
When they arrived, the first thing my in-laws noticed was the pellet trap hanging on the front door. Both of them were anti-gun, but they liked me and knew I was a shooter. Plus, they were very aware that my branch in the army was armor (tanks) which is a very violent combat arm, so they understood that shooting was what I did for a living. Yet…that pellet trap hanging on the inside of the front door really got to them.
Finally, my father-in-law asked me about it. “Why do you shoot inside your house?”
“I do it for relaxation.”
“Isn’t it dangerous?”
“Well, I don’t shoot if anyone else is home.”
“Yes, but what happens if you miss that little trap?”
“Well, I don’t miss, but if I ever do, the door is made of steel, so there’s no danger of penetration.”
“But wouldn’t the pellet bounce around the house and break things?”
“No. It would fall to the floor beneath where it hit. It’s only going about 475 feet per second. It doesn’t fragment at that speed and it can’t bounce back from a flat steel plate like the door. But why worry? The trap is five inches square and I can’t miss it from 19 feet.”
“I sure could!”
“No, you couldn’t. In fact, I’ll bet you couldn’t miss a quarter from that distance.”
[Now, pay attention, folks, because this really happened exactly as I am telling it and it's how I can get YOU to be a 10-meter pistol shooter, too.]
My father-in-law, who said he never shot a gun in his life, looked at me and said, “You think I couldn’t miss a quarter from way back there?” pointing to the back of the hallway. “You’re crazy!” Then he turned to his wife and said, “He’s crazy!”
So, I bet him he could learn to shoot a Diana model 10 target pistol so well that he couldn’t miss an American quarter (about one inch in diameter) from 19 feet. He thought I was insane, but he agreed to try, so when everyone else went shopping, my father-in-law and I stayed home to shoot.
I showed him how to cock the gun, which he thought was hard (it was) and then we started. I asked him to stand five feet from the trap. Naturally we both wore safety glasses. When he extended his arm the way I will show you in the next 10-meter pistol installment, the muzzle was about two-and-a-half feet from the target.
“Well, I agree that I can’t possibly miss from this distance. I thought you meant from back there” (indicating the end of the hallway).
“We’ll get there. But let’s start here. I want you to sight the gun by putting that huge black bullseye on top of the front blade, with the top of the front blade even with the top of the rear notch. Make sure there is equal white space on either side of the front blade.”
So we began. His shots were all below the bull and grouped in a hole the size of a dime. After about 20 shots, I asked him how he felt about it.
“Well, it’s easier than I thought it would be. This trigger is so light that I barely touch it and it goes off. But I’m hitting way below the bullseye.”
“That will change as we move back. Are you ready to try?”
He was, so I moved him back to about 8 feet from the target. This looked like more of a challenge to him, but his shot group was no larger. It did climb on the target just a little, but it was still below the bull.
After another 20 shots, he felt good enough to move way back to 12 feet. Now the shot group was touching the bottom of the black, and it was still dime-sized. After he got comfortable at that distance, we moved back to 15 feet. This looked like a long distance to him and he said so. He could see that the slightest twitch of his hand would throw the shot off the pellet trap. I told him not to twitch. By now he was comfortable enough with the pistol that there were no surprises left. He knew the sights worked, and that what I had told him about sighting also worked. In fact, I had described the same procedure used by top Olympic pistols shooters, so I knew it would work for him. All he had to do was try. He was also used to how the trigger worked, so the chance of a flinch or a “sniped” shot (a shot in which the shooter pulls the trigger instead of squeezing it until it breaks by surprise) had passed.
So he started shooting from 15 feet. His group opened to the size of a nickel (just over three-quarters of an inch), and it also climbed well up into the black. He was concerned about this distance until, after about 25 shots, he saw that he could not miss.
“I never would have believed it, but I guess you were right. I really can’t miss the target.”
“Now let’s back up all the way.”
It was only four more feet, but they were the most daunting of all, because he knew what he had done in such a short time. And now he was about to take the acid test. I had to back up into my bedroom, because there was room in the hall for only one person. That first shot took a long time to come, but finally he fired. Then he lowered the pistol and walked forward until he could see the round hole in the bullseye. It wasn’t in the center, but it wasn’t that far out, either.
After seeing the first shot, he never doubted himself again. He fired about 15 shots and then we both walked up to the target. I’d like to tell you that all the shots were inside the bullseye, but a couple were in the white, close by. Still, the point had been proven. In about one hour this man who had never shot a gun before was shooting at targets from 19 feet and hitting within 1.5 inches. None of his shots ever came close to the edge of the target trap, so he finally understood what I meant when I told him how difficult it was to miss.
I had to leave for tank gunnery the next day, but the folks stayed with my family for two weeks. When I returned a month later, my wife filled me in on the details. Her father had shot up about 3,500 of my RWS Meisterkugeln pellets, practicing with the pistol every day. When he left he was thinking of buying a target pistol of his own. That never happened, of course, because back in the States he fell back into more familiar routines. But he did buy a BB gun to keep the birds out of his apricot trees. As I understood it, he taught his wife to shoot, as well and they both guarded the ‘cot trees in their Campbell, California, backyard from that time on.
This report was part of the 10-meter pistol report, though I haven’t numbered it as such. If you want to learn how to be a better pistol shot, this is how I would teach you. But you don’t need me. You can do this yourself.
by B.B. Pelletier
First things first. Reader K. Rihanek mentioned that the rear sight notch on his Gamo Compact was adjustable, so I read the manual and learned that it is. I have owned a Compact and tested several and never before noticed this feature. You can open that notch to almost double the width via a cleverly hidden adjustment screw on the sight. I’m showing you where it is in case you own a Compact.
Gamo Compact rear sight notch adjustment screw (on the left side of the sight) is headless and hollow. I missed seeing it for 10 years.
This removes the biggest objection I have to the gun. It’s very easy to see a 6 o’clock hold now.
The 6 o’clock hold
Speaking of 6 o’clock holds, Matt61 was describing how he did his, which prompted me to start this series on 10-meter pistol shooting now. Matt was using a center hold, which doesn’t work at all for 10-meter. So, I’ll now show a true 6 o’clock hold.
6 o’clock hold
Now I know that thin sliver of light under the bull is going to unnerve many of you. I can see the comments now – “How thin should it be?” The answer is as thin as you can make it. This is a topic of great discussion among ten-meter shooters the world over.
Some say they don’t leave any light at all, but the majority leave a thin sliver so they can define the bottom of the bull above the front sight.
Please remember what a 10-meter target looks like and where the scoring rings are.
This is an official 10-meter target. Six o’clock means the extreme lower point of the 7-ring, which would be 6 o’clock if the black bullseye were a clock face.
Adjusting the sights
The sights are adjusted so the pellet ends up in the center of the 10-ring, and this is done while shooting offhand. No 10-meter competitor would dream of shooting his gun from a vice to sight in, because he knows the gun will shoot to a different point when handheld. Which begs the question, “How can you possibly sight-in a 10-meter pistol when you can’t even hit the center of the bullseye most of the time?” Think of it this way: Shooting 10-meter pistol is a lot like riding a unicycle. It requires a skill that most people don’t have. You just start trying and eventually you get better. Finally, you remain upright on the cycle all the time.
In 10-meter shooting, you start out with a sight setting that gets you the highest number of points. As you progress, you start noticing that although you’re shooting all over the 7-ring, your pellets are landing in the lower right quadrant of the ring more often than anywhere else. You make a sight adjustment to move the pellet slightly up and to the left. To your surprise, your 10-shot average score climbs from 74 to 81. The sight correction actually helped!
The importance of follow-through
This goes on until the day you notice that if you hold your sights on the target a moment after the shot breaks you can see where the sights were when the gun fired. To your surprise, you’re now able to “call your shots,” which means when you say a shot is high and to the left, that’s where it goes. All of a sudden, you start trying to follow through intentionally, and your average increases by three more points.
The front sight is everything
Then, a day comes when you notice the front sight has more to do with where the shot goes than anything else. Now, you start concentrating on the front sight to the point that the rear notch and the bull become blurry. The fact that you are 60 years old and wear reading glasses suddenly doesn’t matter anymore. You’ve discovered the SECRET! Your average score increases by another point. You’re now shooting an 85 for ten shots.
The next big thing to happen is that the trigger begins to break without your conscious effort. You’re lined up on the shot and the gun suddenly fires before you thought you were ready. It increases your score by seven points. You now shoot a 92 average, which means a score of 552/600 in a men’s match or a 368/400 in a women’s match. At this point, you’re an NRA Expert shooter and any advance from here will require a change in your thinking. Target shooting is a head game, the same as any championship competition. That’s why the books about expert marksmanship all sound like a lesson in Zen. You need to concentrate on the target to the exclusion of everything else. Please watch the movie The Greatest Game Ever Played or the movie For Love of the Game to understand what I’m talking about.
Wax on – wax off
For many of you, this report reads like new-age gibberish – except for the part about the 6 o’clock hold. In fact, this report actually is a condensed course in how to become a 10-meter champion. But you’re not ready for that, yet, so I’m giving you an assignment to watch what I consider to be the finest instructional video of all time on becoming a champion. Please watch The Karate Kid. When I say, “Wax on – wax off” from now on, I expect you to understand what I’m talking about.
Matt61, you asked me about my friend who became obsessed with 10-meter shooting. He read everything I wrote, and watched all the films I recommended, and, within 18-months, he was out-shooting me. My top average score with the NRA was a 535. That equates to an 89.16-point 10-shot average. My best individual score in a match was a 545. When I shot it, I was on the cusp of breaking through the 90-point barrier and moving from Sharpshooter to Expert in 10-meter competition. Then we moved and I lost my chance to shoot every day, so today, five years later, I’m lucky to shoot a 475. But I have been there and I know what it takes to get you there.
Rules of 10-meter pistol matches
A 10-meter pistol match is shot at 10 meters from the muzzle of the pistol. Because each shooter has a different arm length, it is physically impossible for them all to be exactly at 10 meters, so the firing line is set up so that no shooter’s muzzle will be closer than 10 meters. There will be differences of several inches among all the muzzles on line. Shooters don’t worry about that. They simply confirm their zero before the match and go with it. A few inches doesn’t make a difference with these guns.
Introduction by B.B. Pelletier
Here’s another guest blogger. Vince Brandolini shows us how he shims a Diana breech seal to gain more energy. Vince has instructed several readers on this blog how to do this and they report similar velocity gains.
If you have an airgun story to tell, maybe you can tell it here. I’m looking for some budding bloggers who would like to help me write this blog. If you would like to write a post for this blog, please email me at firstname.lastname@example.org.
Bloggers must be proficient in the simple html that Blogger software uses, know how to take clear photos and size them for the internet (if their post requires them) and they must use proper English. We will edit each submission, but we won’t work on any submission that contains gross misspellings and/or grammatical errors.
Okay, Vince – take it away!
Shimming the Diana breech seal
By Vince Brandolini
I had gotten my first Diana rifle about 15 months ago – a wood-stocked RWS 34. I found it to be a bit of a disappointment in several respects and ended up selling it after a few months. One reason was the velocity; it generated under 14 ft-lbs at the muzzle. That’s no big deal, but the rifle certainly took more effort to cock than, say, my Gamo Shadow or Crosman Quest, either of which would handily out-power it.
Giving the 34 one more chance
Still, I did sort of miss the rifle. After hearing a lot of good things about the Panther variant of the ’34 (including BB’s review), I decided to take a crack at one. The example I got was a factory-refurbished model, and, frankly, all the reviews were right on the money. It was a much nicer gun to shoot overall, although the velocity was still low.
It didn’t worry me too much until I compiled a list of the mechanical specs of all my springers – including the potential energy stored in the powerplant when the gun is cocked. I then bounced that number against actual muzzle energy and found that all my guns came out at over 30% efficient – except for the Panther which came in at less than 28%. That didn’t sound right to me.
Huge increases in efficiency & velocity!
My suspicions were confirmed when I obtained a .22 caliber Panther a short time later, and it was lobbing Crosman Wadcutters under 600 fps (under 25% efficient). After some investigation, I found that shimming the breech seal resulted in a velocity over 700 fps. That made me wonder about my .177 Panther. So, I shimmed THAT breech seal and the velocity (10-shot average, 7.9 Crosman Premiers) went from 868 to 938 fps – a 17% increase in power and a new efficiency of 32.5%. Incidentally, the efficiency of the .22 is now close to 37%.
Dianas aren’t the only guns that could use a shimmed breech seal
When I found a similar problem with my very recently acquired Ruger Air Hawk (which is a BAM-built semi-clone of the ’34), I began to wonder if this might be a common issue.
How it looks on the inside
Below is what the typical Diana-type breech and seal look like (the pictures are from the near-identical Ruger Air Hawk).
Making & installing the shim is just about a no-brainer
This isn’t an expensive or time-consuming process and no mechanical knowledge is required, yet I found it was one of the quickest ways to immediately get a velocity increase. Let’s get to it!
The seal groove on the Ruger Air Hawk has a .540″ outside diameter and a .340″ inside diameter (measurements are approximate).
The shim can be made out of a variety of materials. Diana uses steel, while Crosman (with a similar setup) uses a thick paper. I settled on plastic from a coffee can lid, which yields a pliable shim about .015″ thick, and aluminum from a soda can, which is about .005″ thick.
Making the shim is a simple 2-step process…
The same procedure is used regardless of the material. If you use aluminum, the punching process will probably distort the ring, so make sure you hammer it flat before installing it.
What if you need to replace an o-ring?
If you discovered that your gun’s o-ring is torn, gouged, ripped or in some way damaged because that’s how it came in the gun or because you did something when removing from your gun, you can buy a replacement. I checked into Umarex’s replacement breech seals, and found that they charge $4-5 for one. If you need only one, that might be the way you want to go. On the other hand, I was able to buy a bag of 100 McMaster-Carr o-rings for just $3.
Installing the shim
A few minutes of work increases velocity
Yes, it’s still slower than my Panther, but the Air Hawk isn’t a perfect clone. The powerplant has a shorter stroke (by about 15mm) and a slightly softer spring. Out of the three guns I shimmed, this one improved the least. But, the improvement is unmistakable (it was observed over a series of several shots), and it brought the powerplant efficiency up to a reasonable 32%.
Later, I found a fiber washer from McMaster that seems to work well as a breech seal shim. It’s part #90089A330 and sells for $10 for a bag of 100. It’s about .016″ thick, so it won’t do if you’re trying to shim a very small amount.
This naturally leads to the the question – how do you know if your rifle needs it, and how much should you shim? There’s no set rule. My Diana 350 didn’t need any shims, and frankly I don’t know of any way of telling beyond trial and error. There’s a “wax paper test” for a leaking breech seal: load the gun and put a strip of wax paper between the breech and the compression tube as you close the action. Fire the gun. If the seal leaks, it’s supposed to tear the paper. Perhaps this works in some cases, but it didn’t work for me.
That’s about it. I suspect that my first 34 (the one I sold) suffered from this problem. Plus, Hank wrote that his .22 Panther gun picked up 100 fps.
by B.B. Pelletier
Today, we’ll look at the accuracy of the Gamo Compact pistol, and I will try my new pumping technique to see if it produces any faster shots.
General comments about shooting the gun
Now that I’m shooting at targets, I can make accurate comments about shooting the Compact. First, the grips are too large for my hands. I would need a serious session with a round rasp and sandpaper to fit them, however that’s a good thing because it’s easier to take wood away than to add it.
The sights gave me difficulties while shooting for record. The rear notch is so narrow that only under perfect conditions was I able to see light on both sides of the front post. Were this pistol my own, I would open the notch by 50 percent.
The trigger-pull is still on the heavy side. This is magnified by the large grips, so if they were altered the trigger might become easier to pull.
A word about the shooting
I shot from 10 meters, but I rested my arm instead of holding it offhand. I did this to show the accuracy of the gun unhampered by my own abilities. I haven’t shot competitively or trained in five years, so I didn’t think it’s fair to hinder the gun that way.
A 10-meter target is an official target on target paper. The 7-ring is the outer ring of the black bull and it measures 2.362″ across, or 60 mm. The inner ring is not the 10-ring. It’s used for fractional points accessed during shootoffs. In the U.S. we might call the inner ring the X ring, but it’s more than that. The second smallest ring is the ten-ring. Neither it nor the 9-ring are numbered on this target.
This is an official 10-meter target.
I sighted-in with Gamo Match pellets, but they ripped the paper too much for good scoring. Once I was on target, I switched to H&N Finale Match lightweight pellets.
H&N Finale Match
These were the most accurate pellets in this pistol. They also cut the paper reasonable well, though they did tend to tear a bit too much. Still, in a match you never shoot more than a single pellet at a target, so it doesn’t really matter.
This is a score of 50 for five shots – a perfect score. Shot with H&N Finale Match.
RWS Hobby pellets are not too bad in the Compact. They group almost as well as H&Ns, though I wouldn’t compete with them.
This is a score of 49 for five shots. Shot with RWS Hobby pellets.
Now, let’s see what the pistol does when I use the new pumping technique. RWS Hobbies averaged 398 f.p.s., ranging from 387 to 408. As the gun was fired, the average was creeping upward, so after a long shooting session it might be even slightly higher. Before, when I just pumped the gun in the conventional way, it averaged 370 f.p.s. after 50 warm-up shots. So, the gain is 28 f.p.s.
With H&N Finale Match, the average was 389 f.p.s., with a spread from 383 to 396. Before, with the conventional style of pumping, the average was 366, so the gain was 23 f.p.s.
Clearly, the Gamo Compact can shoot well. It’s the kind of gun that a shooter needs to customize to his own tastes. Once that’s done, it can be a very competitive target pistol. The heavier trigger and narrow rear sight notch should be addressed before you attempt any competition, so be prepared for that.
Also, this new pumping routine really seems to bring out the best in single-strokes. If you own one, give it a try.