Posts Tagged ‘accuracy’
by Tom Gaylord, a.k.a. B.B. Pelletier
A couple weeks ago we had several comments that said there are people who believe all pellets are the same, and it doesn’t matter what you shoot in your airgun. Then others chimed in and said the same is true for .22 rimfire ammo. Well, I started a test of .22 rimfire ammo last week and hope to finish it soon, but today I thought I’d start exploring the pellet side of the question.
Today was supposed to be a first look at the accuracy of the BSA Supersport SE; but for the first time that I can remember, I couldn’t get the open sights on target at 25 yards! I didn’t want to fool with the rifle for a long time, so I set it aside and picked up my super-accurate Beeman R8 Tyrolean. That’s a rifle I know I can count on.
My original plan was to buy .177 pellets from wally world and pit them against the best premium pellets I have; but since this was a last-minute test, I just selected some pellets from my supplies. I made this a Part 1 because I still intend doing what was planned.
Today, we’ll look at 4 pellets. Two are what I consider premium, though one of them is pointed and I usually don’t shoot pointed pellets for accuracy. That should be interesting.
The other 2 pellets are ones I actually bought at a discount store some time ago. They’re representative of what’s out there right now. One’s a wadcutter; but since I’m shooting indoors at 25 yards, I felt it might still do its best. The other is a pointed pellet that Crosman made for Remington several years ago. These 2 pellets are the ones I believe will not do well.
I shot the rifle at 25 yards rested directly on a sandbag, which I’ve determined works well for this gun. In the entire test, there were no called fliers.
Air Arms Falcon
The first pellet I tested was the Falcon from Air Arms. It’s made by JSB on dies owned by Air Arms, so there’s no equivalent JSB pellet. There are several that look similar, but testing shows they perform differently. Ten Falcons went into a group that measures 0.667 inches between centers. You can see a single pellet hole to the right of the main group. That was the third shot. Nine of the 10 pellets went into 0.399 inches.
This group of 10 Air Arms Falcon pellets measures 0.667 inches between centers, but 9 of them are in 0.399 inches at 25 yards.
I normally don’t recommend pointed pellets for accuracy; but 25 yards isn’t that far, and RWS pellets are certainly in the premium category. I didn’t expect RWS Superpoints to do as well as the Falcons…and they didn’t. But they were close! Ten made a group measuring 0.732 inches. Once again, one pellet was outside the main group, and 9 pellets went into 0.43 inches
Now, it was time to test the 2 pellets in which I didn’t have any faith. I still tried as hard as possible to shoot the best group. Frankly, I’m surprised they did as well as they did!
Daisy Precision Max wadcutter
The next pellet was a older pellet I had that is similar to the Daisy Precision Max wadcutter – a flat-nosed target pellet. I didn’t expect it to do much, but 10 of them went into a group measuring 0.804 inches. And, to be fair, 9 of them are in 0.591 inches. While that’s not great for this particular rifle, it’s a lot better than I expected.
Remington pointed pellets
The last pellet I tried was one Remington sold for many years, but one that Crosman made. So, it has a sort of premium heritage, though the discount store pellets that Crosman sells (which is where I got this tin) are not normally as good as the ones they make for their cardboard boxes — by which I mean Premiers, of course. I didn’t know what to expect from these pellets. Ten went into 0.821 inches, which is better than I expected, and 8 of them went into a group that measures 0.402 inches. That’s hard to argue with.
Ten Remington pointed pellets made this 0.821-inch group. Eight went into 0.402 inches.
This test worked as expected, but it wasn’t as conclusive as I’d hoped it would be. Clearly, I need to look harder into these discount store pellets.
The Beeman R8 rifle is really an accurate platform that makes all these pellets look good. I think it’s a great testbed, but I won’t rule out trying the same test with a different rifle at a later date.
I could run the test at 50 yards, and the groups would all open up a lot — but that isn’t what I’m testing. Most airgunners don’t often shoot at 50 yards. I think 25 yards is more representative of what they do most of the time. I think I’ll just stick to the original plan of buying some representative pellets at a discount store and pitting them against the best premium pellets I have.
by Tom Gaylord, a.k.a. B.B. Pelletier
Today’s report is a guest blog from duskwight, our blog reader in Moscow. It’s a report of a test to determine if changing the power of a variable scope affects the potential for accuracy
If you’d like to write a guest post for this blog, please email me.
Over to you, duskwight.
How scope power affects accuracy
Hello, my airgunning friends! This is a report of a small test I performed recently to see if changing the power of a rifle scope affects the accuracy potential in any way. I guess the thing I’m testing is if you need to see the target as large as possible for aiming precision, or if you can be just as accurate when it appears smaller, because the crosshairs of your scope will still be in the same place.
B.B. tested this for me last week and reported it in the most recent test of the TX200. He shot two 10-shot groups at 50 yards with the scope set on 4x and 2 more with it set on 16x. In the first set of targets, he admitted that he wasn’t holding the rifle as good as he could and the 16x group was smaller than the one shot on 4x. But in the second set of targets, when he said he tried his best, the 4x group was smaller than the 16x group.
B.B.’s test was shot outdoors with a recoiling spring rifle. I decided to shoot mine indoors with a modified Gamo CF-X spring rifle I built. I call my rifle the Shillelagh, and I’ve taken a picture so you can see what it looks like.
My Shillelagh (Gamo CF-X) was used for this test.
I’m shooting indoors, so wind isn’t a factor. The air is dry and the temperature is 20 degrees C, or 68 F. I am shooting off a soft rest like B.B. used with the TX200. The distance is 50 meters, and my targets are made of 2 black circles, the inner one 1/2″ in diameter and the outer one 1-1/2″ in diameter. I’m measuring the groups from the outsides of the pellet holes farthest apart, and my groups each contain 10 shots.
I decided to select the power settings 6 and 12 magnifications for this test. I shot 2 groups on each magnification. In one set of targets, I concentrated on the hold very much; and on the other set, I went faster, with less concentration. Let’s take a look at the results.
The first group that was fired on 6x with extreme concentration measured 0.906″ across the outside of the group at the widest point. If we use a nominal .177 inches for the pellet diameter, that group would then measure 0.7295″ between centers.
This 10-shot group came with the scope set at 6xr and using extreme concentration. The outside measurement in 0.9065″; and using 0.177″ as the pellet diameter, the center-to-center measurement is 0.7295″. Nice to know my Shillelagh can shoot!
The first group shot with the scope set at 12x and using extreme concentration measured 1.4455″ across and 1.2685″ between centers. That’s quite a bit larger than the 6x group!
This 10-shot group was made with the scope set at 12x and using extreme concentration. The outside measurement in 1.4455″ across; and, using 0.177″ as the pellet diameter, the center-to-center measurement is 1.2685″. Quite a difference from the 6x group.
More relaxed shooting
Now, it was time to shoot groups from a more relaxed rest. I tried just as hard, but things went faster this time. The first group was shot at 6x and measured 1.003″s across the outside. The C-T-C measurement is 0.826″. Also not too shabby!
Here are 10 shots with the scope set at 6x with a more relaxed shooting style. The outside measurement is 1.003″ across, and the C-T-C measurement is 0.826″.
Next, I shot another 10-shot group in the more relaxed style with the scope set on 12x. This group measured 1.7325″ across, which gives us a measurement of 1.5555″ between centers. This is the largest group of the test and more than double the size of the first group shot on 6x.
Ten shots with the scope set at 12x with a more relaxed shooting style measured 1.7325″ across, and the C-T-C measurement is 1.5555″. This is the largest group of the test.
It’s clear to me that lower magnification isn’t any hinderance to accuracy, as long as you can see the target clearly. In fact, I think lower magnification is the way to go.
I made a huge mistake when I edited this text for duskwight. I assumed that his Shillelagh is his recoiless rifle project, when in fact, it’s a highly modified Gamo CF-X. The rifle seen in this test is that Gamo CF-X. I apologize for the confusion this has caused. — B.B.
Some of our newer readers probably don’t know the story of how duskwight built a recoiless spring rifle from scratch. Like you he was a reader of this blog and he was also an airgunner before finding this blog. He knew about the famous Whiscombe rifles, but they were hard to come by — even when John Whiscombe was still making them. Adding the extra difficulty of getting one all the way to Russia made him think about building his own rifle. When he first told us his plans, I thought it would never happen; and he shared all his struggles with unreliable machine shops and companies that could not meet his specifications. It seemed as though it wasn’t meant to be.
But he persisted, and finally, he had a working prototype. It took years of effort…and I don’t want to know how much money. But he did it. Then he sat down and whittled out a stock from a raw wood blank.
This Gamo CF-X, which he calls the Shillelagh, is just one example of his expertise building custom airguns. I think the accuracy he got with it is quite stunning!
Duskwight is Russia’s airgun answer to New Zealander Bert Munro, who took a 1920 Indian motorcycle and modified it into a 200 m.p.h. streamliner in the 1960s! People like this are in extremely short supply, and it’s our honor to know this one!
by Tom Gaylord, a.k.a. B.B. Pelletier
I was getting ready to go to the range yesterday to shoot several airguns for this blog. When I go to the range, I usually try to take a couple of firearms along, just to justify the time and inconvenience of loading the truck and driving all the way out there. The range doesn’t cost anything, but the time spent getting there, setting up and getting back home again seems like an expense.
Anyway, I decided to take my Desert Eagle .357 Magnum pistol along this time, to find a good long-range cartridge for it. Up to this point, I’ve just function-fired the gun for a couple hundred shots or so at shorter distances because I read on the internet that this gun is unreliable with lighter bullets. Well, I’ve shot only 125-grain bullets that are considered light for a .357 Magnum, and to date the gun has never malfunctioned once. So, that much of what I read turned out not to be true!
Monday morning, I’m was online looking for some good accurate loads, and this is what I found:
“I don’t own a Desert Eagle .357, but I have read that they are unreliable boat-anchors. They are way too heavy and they recoil too hard! I don’t need that. They also cost three times as much as my Taurus wheelgun. Why would I spend that kind of money, just to have a gun that jams?”
So, you DON’T own a Desert Eagle? Then why are you commenting on its performance? I’m all for open discussions; but when you don’t have any experience, why not just say what you’ve heard and ask whether or not it’s true?
I DO own a .357 Magnum Desert Eagle and here are the facts. They DON’T kick very hard. They feel about like a 1911 pistol shooting Plus P ammo when they shoot full-house .357 loads. And they DON’T malfunction! At least mine has never failed to feed — ever! They ARE heavy, but I don’t find it debilitating to carry a 5-lb. pistol from my truck to the firing line — a distance of about 20 feet.
Then, I found another website with guy who lists all the factory ammo brands that don’t work well in his Desert Eagle. Excuse me, but who said anything about shooting factory ammo? I reload! Why would I care if one brand that does function costs more than another brand that has feeding failures? I’m going to make up loads for my gun that ALL WORK. Who buys an expensive handgun like a Desert Eagle and then shops in discount stores for the cheapest ammo? That’s like going to a 5-star restaurant and looking for their dollar menu. If you want to save money so bad, cut a slot in your head and become a bank.
Finally I find the worst one of all. I swear I am not making this up:
“When I shoot targets, I shoot Winchester White Box (a type of commercial ammo) in my DE. It’s the cheapest stuff I can find locally. I used to shoot some Lapua imported stuff that was really accurate, but it cost a lot more than the U.S. stuff. I can’t tell you how accurate any of this is, but most of the really hot stuff cycles the action fine.”
Is the last writer shooting his gun just to hear the sound? Is it News Year’s Eve and this is his noisemaker? What is he doing? He says he shoots targets, but he can’t tell me how accurate any of the ammo is. Is he closing his eyes when he shoots? Does he just shoot at the targets and then never looks to see if he hits them?
Applying this to airguns
I know what this guy is really trying to say, but he can’t find the words. He’s saying that he uses his Desert Eagle as a bragging-rights gun, and he doesn’t care how accurate it is. He doesn’t shoot it to hit things — he wants to be seen shooting it and to be able to tell his buddies that he shoots a Desert Eagle.
I’ve seen enough guys like this at the range to know what I’m talking about. A couple weeks ago, a man at my range was warning everybody on the line that he was about to shoot a .300 Winchester Magnum, and everyone should be careful of the blast! When he shot his rifle, it was anticlimactic because the guy next to me had been shooting a 7mm Remington Magnum for the previous hour that made just as much noise. But Mister Win Mag wanted to be noticed, and he needed to draw attention to the fact that his rifle was a tactical nuclear weapon!
And this is how it applies to airguns. These same folks buy those 1,600 f.p.s. breakbarrel cannons and shoot ultralight lead-free pellets in them. If they do shoot at anything specific, they aren’t paper targets — they’re probably metal plates. Then, they can determine how much mild steel their pellet gun is able to penetrate, and at what distance.
Everything they do is a weird science experiment. They’re the ones who wind up on You Tube with blood pouring out of their ears while their friends laugh maniacally in the background.
That’s not airgunning! That’s being back in the fourth grade and trying to light…well, you know what I mean. And if you don’t, you’re probably still doing it. And you aren’t reading this blog, either, because people like that don’t read much of anything longer than the label on a beer can or a juicy tweet on Twitter.
I shoot airguns to augment my shooting experience. And the point of that experience is to maintain and perhaps improve my shooting skills. Small groups are important to me, but so is standing on my feet and shooting the center of a target offhand — as I have done in front of witnesses several times.
I’m in this game to place my shots where I call them, or to know that I haven’t whenever something goes wrong. I’m in this partly to keep my shooting skills sharp and partly to find guns and pellets that can shoot better than I can.
And that’s what’s behind all my reviews. Sure, I like a nice trigger; but without accuracy, a good trigger is like a rusted-out car that has a deep, resonating tone coming from the tailpipe. HEY — I once owned a VW bug with a stinger exhaust that was just like that! It sounded like an expensive sports car and ran like a model A Ford delivery truck.
So, manufacturers, I am warning you here and now — send me your guns and you can expect me to shoot them for accuracy first, and all other things second. I will use every trick I know to make your guns shoot well…and with luck, they will. But if they don’t after I’ve exhausted all attempts to the best of my ability, you can expect me to tell everyone about how it really performed.
So, send me your mega-magnums. Just make sure they’re also accurate. Send me your gilt-edged light sabers, but expect me to turn them on and attempt to use them. I can put up with a lot of things when I shoot, but missing the target because my gun is throwing curveballs isn’t one of them.
The lesson of the wise barber
The wise barber said you can cut a man’s hair every month, but you can only scalp him once. Marketing departments and airgun manufacturers need to internalize this wisdom because putting a bone-jarring air rifle into a customer’s hands may be the ticket to losing him forever. On the other hand, give him a gun so good he’ll want more, and you have created a loyal customer. His business won’t just be worth the $300 he spends today, but tens of thousands of dollars that he’ll spend with you over the next 40 years as he enjoys his hobby.
by Tom Gaylord, a.k.a. B.B. Pelletier
Today’s blog is going to be fun for me, and I hope for all of you, as well. I’m going to talk about one of my favorite subject — the accurate gun. You have to be a shooter to know what I’m talking about because non-shooters assume that all guns are accurate. They assume that it’s the skill of the shooter that makes guns work like they do.
That’s like saying all violins are the same, and a master can make a student instrument sound like a Stradivarius. Or a NASCAR driver can make a minivan perform like a Ferarri. But it doesn’t work that way. While expert handling can extract all the performance from anything, no matter what it is, there’s also no way to get more than it has to offer, regardless of who wields the bow or sits behind the wheel. Or, in today’s case, is on the trigger!
Accuracy is something that lives in the gun. And, in my experience, a really accurate gun isn’t that common. Though I shot a lot starting in my late youth, it wasn’t until I acquired a custom .458 Winchester Magnum in my twenties that I encountered my first really accurate gun. I bought…or more likely, traded…for the rifle at a local gun show when I was living in El Paso, Texas, in the early 1970s. It was a 1903 Springfield that had been rebarrelled to .458 Winchester Mag.; and it came with the reloading dies, a bullet mold, a batch of empty brass and even a recommended load. The seller/trader told me if I loaded it with his load, the rifle would be phenomenally accurate. I’d heard that before, but not as many times back then as I have today. In spite of my doubts, I did the deal.
I cast up some of the 558-grain lead bullets and loaded up the exact formula the seller had recommended, which I recall was 24 grains of 2400 powder and a greased but unsized bullet seated to a certain depth in the case. Then, I went to the range. Since this was a .458 Winchester Magnum, I was prepared to be kicked hard, but that load was so soft that it was very pleasing to shoot from the bench. When I checked the first 5-shot group at 100 yards and saw that it was only an inch across, I was thrilled!
That’s when I began shooting 10-shot groups, because, try though I might, I could not get those big lead slugs to go anywhere but through the same hole. In fact, the accuracy of that rifle became downright boring after awhile. I would load up 40 rounds and shoot 4 groups that were all less than 2 inches across at 100 yards. Big whoop! There was no challenge.
I didn’t know then that I would never again have a rifle so inherently accurate. I just assumed that was the way of things, so I eventually sold or traded that rifle…and have lamented the decision ever since.
This is why I want so much for my Ballard rifle to shoot well — because I believe that it can! If that old put-together Springfield sporter could lob them all through the same little hole, there’s no reason a purpose-built target rifle made in 1876, when American gunmaking was at its zenith, shouldn’t do the same.
My Ballard rifle is beautiful. If only it shot like it looks!
So far, the Ballard has been a heartbreaker. She taunts and teases me with her looks and then puts 7 out of 10 bullets through the same hole, while scattering the other 3 wherever she pleases! Time after time, I thought I found the secret and was about to turn the Ballard into the thoroughbred she is, and just as many times I’ve been disappointed. When that happens, I get so discouraged that I have to abandon shooting the rifle altogether and do something else. There have even been times when I’ve thought of selling the rifle just to get it out of my sight. But, then, I look at her and realize that I have to keep trying.
My latest theory is that the rifle needs a shorter bullet because the twist rate is very slow. It’s 1:20, where a normal .38-55 twist is 1:18. That would mean the 255-grain bullets I’ve been shooting are too long to stabilize. Please understand that I’m using smokeless powder in my reloads, and this rifle was designed for black powder. With black powder, you fill the case as full as it will go so there’s no empty space between the powder and bullet. If there were space, the powder would develop a shockwave that would destroy the rifle!
But smokeless powder doesn’t fill the case, and the pressure rises faster than black powder, so I have to keep the charges low. As a result, the gun cannot fire the bullet fast enough, even though it was designed to shoot that bullet. Because of that, it can’t stabilize it properly. At least, that’s my guess.
Another problem is that there’s no leade ahead of the chamber. The rifling rises up at the end of the chamber and that’s it. A bullet with a fat nose won’t chamber properly, as the rifling will prevent the bullet from being seated.
What I need is a custom bullet for this rifle and to own the mold made for it. I’m working on that right now.
I got an O3A3 Springfield from my buddy Mac a couple years ago. Most Springfield rifles are accurate in the general sense, but this one is special. It lays them in there better than it should. I can pull a sub-2-inch group at 100 yards when I do my part, and that’s with the battle sights that came standard on the rifle.
They made millions of them, but this one is special. It’s more than accurate — it doesn’t like to miss.
The O3A3 was the last incarnation of the famous 1903 Springfield bolt-action battle rifle. It was made during World War II to fill the need for rifles until Springfield could catch up with the Garand production. What made it an O3A3 were several minor design changes that substituted stamped and welded assemblies for machined parts. Oh, the hue and cry about that was great! Even in the 1960s, old soldiers still bemoaned the cheapening of the Springfield rifle!
But there was a funny side to it, as well. The cheaper rifles were also often more accurate! Instead of the antiquated Buffington peep sight that had been around since 1884, the O3A3 has a modern rear peep sight that adjusts for both windage and elevation. And mine has a 4-groove Remington barrel that’s renowned for accuracy. Put the package together, and you have an American battle rifle that shoots like a target gun. The one I have does even better than most.
For 1884, the Buffington rear sight that combined a peep with an open notch was high-tech. It was used on all U.S. rifles through the M1903 Springfield, but it’s dated today!
The O3A3 rear peep modernized the Springfield rifle during WWII. It made the rifle easier to shoot accurately.
It’s a natural shooter! For some reason unknown to me, my O3A3 puts all its bullets where I want them — with iron sights! When Mac traded it to me, he apologized for the Social Security number that some former owner engraved on the receiver with an electric pen. It’s barely visible, but its presence makes this 99-percent rifle a $600 shooter rather than an $1,100 collectible. But there’s also an upside to that. I don’t have to worry about the wear I’m causing by working the bolt because all the value has already been taken away.
I’ve owned six 1903-type Springfield rifles in my life. All of them were accurate, but this one is special. It goes beyond being accurate and crosses into a realm that’s hard to define. Those readers who own accurate guns will understand what I’m saying.
I’ve owned super-accurate handguns, too. One of them is a revolver I got just recently in a trade. It’s a gun I never would have considered before shooting 12 rounds offhand into pretty much one hole at 15 yards a few months ago. And the caliber — .32-20, which is also called .32 WCF — is a caliber I thought I would never own.
The gun is a Smith & Wesson Hand Ejector with target sights. It’s from the 1930s and shows it’s heritage proudly. It was carried for years in a handmade leather holster until the owner, my pal Otho, finally decided the gun had become too valuable to carry anymore. He no longer shoots handguns for medical reasons, so he was kind enough to let me try his pride and joy earlier this year. When he saw that I shot it well, too, he offered it to me.
This 32-20 S&W Hand Ejector looks dated, but it shoots like the target pistol that it is.
Most revolvers have one chamber that’s just a little out of line with the barrel and shoots just a little off. This one has six good chambers that you can’t tell apart downrange. But that’s understandable; because when it was made, Smith & Wesson used skilled craftsmen to fine-tune their revolvers — especially those with adjustable sights.
I own lots of accurate firearms and airguns, but today I’ve been discussing something more than that. The guns I’ve mentioned, with the exception of the Ballard, are beyond accurate. They have something that’s hard to define and harder to give a name to. When I pick up one of them, I know where my shot will be going — every time! I don’t know what to call this thing I’m talking about, but it does warm my heart to shoot one of these special guns.
by Tom Gaylord, a.k.a. B.B. Pelletier
This is an ongoing series about scope questions and issues. Blog reader David Enoch asked for it originally, but many other readers have jumped in since it began. Today, I’ll talk about adjustable scope mounts.
First things first
Why do we need adjustable scope mounts? Aren’t the scopes, themselves, supposed to adjust? Yes, they are, but 2 things quickly become a problem. First, the scopes don’t adjust as far as we need them to; and second, when a scope adjusts toward its upper and right limits, it loses its precision. I will address the second problem because it’s really the principal one.
When we look at a scope, we see that it has a range of adjustability and assume that it’ll work as it should throughout this range. But that’s not the case. Inside each modern scope there is a smaller tube called the erector tube. The erector tube often contains the reticle; and as the tube moves up, down, left and right, so does the reticle. So, moving the erector tube is what moves the reticle.
There is a spring or springs that press against the erector tube, making it press against the adjustment knobs, in turn. That spring has a range of movement it goes through as the tube moves. When the tube is up high or far to the right, then a spring or springs that press it against the adjustment knob or knobs are relaxed and can allow the erector tube to move when the gun vibrates, such as with a shot. This is one of the chief causes for “scope shift.” You fire the gun, and the erector tube moves slightly, taking the reticle along with it, of course. On the next shot, the scope will be aiming at a slightly different place. It’ll appear that your scope is wildly throwing the shots around.
This elevation knob is adjusted up to its maximum limit. I recommend not adjusting it higher than the number 3 line on a scope like this to avoid scope shift.
I tell folks that a good rule of thumb is to not adjust their scopes above the 3/4 mark on the elevation knob or past the 3/4 mark on the right windage adjustment. Some scopes can adjust farther than this without a problem; but the closer you stay toward the middle of the range, the better. If your scope doesn’t have knobs like these, you may have to count the actual clicks of adjustment to know where you are.
Is adjusting the scope in the opposite direction (i.e., down or to the left) a problem? No, it isn’t. You can adjust all the way until the adjustments run out in the down and left directions. It doesn’t hurt the scope, nor does it affect accuracy.
So, the scope that you thought had a huge adjustment range turns out not to have as much as you believed. Yet, your airgun (or firearm) needs more adjustment than you have. How do you compensate for the adjustment you no longer have but may need? With a scope mount that adjusts, of course.
Adjustable scope mounts
The purpose of an adjustable scope mount is to align the axis of the scope in a direction different than the scope base on the gun dictates. If all scope bases were aligned with the axis of the barrel, there wouldn’t be a problem, but they aren’t. Adjustable scope mounts can compensate for this, leaving the scope’s internal adjustments to serve the ballistic requirements of the gun in question.
Up and down, left and right
A barrel can point off from a gun’s scope base in any direction, but the most common direction is down. The barrel “looks” down, in relation to where the scope tries to look. The other 3 directions are also possible, with left being the second most common. After that, the other 2 directions happen pretty infrequently.
So, if you’re going to need extra adjustments, it will most likely be extra “up” that you need, followed by extra “right.” Adjustable scope mounts have to provide extra scope movement in all directions, with up and right being needed most often.
Scope tube integrity
The scope tube is a hollow, rigid tube that must maintain its integrity to keep the lenses in alignment. If the tube were to bend, it could seriously damage or even break the scope. Adjustable scope mounts must either move the scope as a whole without putting any stress on the tube, something that only a 1-piece mount can do; or they must adjust in such a way that when the rear mount moves, the front mount can relieve the stress on the scope tube. Only the B-Square AA adjustable scope mounts were able to do that; and when B-Square sold the company several years ago, the new owner moved the manufacture of the AA adjustable mount to China, where the quality control was soon lost. You cannot buy new AA adjustable scope mounts any more.
When the rear mount is raised above the front mount, if the front mount doesn’t move to compensate, the scope tube will be strained. These B-Square 2-piece AA adjustable mounts have rings that pivot forward to allow the scope tube to remain straight.
Sports Match has 2-piece adjustable mounts on the market; but as far as I can see, they make no provisions for relieving the stress on the scope tube when the rings are adjusted separately for elevation. I guess I need to test them to learn their operational parameters. I don’t see how they can avoid stressing the scope tube when the front and rear mount are at different heights, but I’m willing to hold my opinion until I’ve examined them.
I’ve tested several 1-piece adjustable scope mounts and found all of them to work well in this regard. Most recently, I tested the BKL adjustable mount and found that it moved well in both directions.
What about precision?
To date, no one has made an adjustable scope mount that adjusts with precision for a modern scope. Such mounts do exist for vintage scopes that have no erector tubes because the entire scope has to be moved by the mount. I have shown you this kind of adjustable scope mount a couple times.
This Unertl scope ring adjusts to move the entire scope. It has the same precision as the adjustments on a modern scope.
Slippage is common with adjustable scope mounts
The most common problem is the adjustable scope mount that does not hold its position. That’s why the Chinese-made B-Square adjustable mounts failed. Their screw holes had sloppy threads that tore out under stress, and the mounts couldn’t hold in position. So, whatever adjustable mount you get, it must hold its position once it’s been adjusted, or it won’t work.
And slippage happens soonest on spring guns because of their recoil and vibration. Ironically, spring guns are the very ones that need the adjustable mounts most often. There’s nothing that can be done about this, but you must understand that you don’t want a scope mount that can’t hold its position.
Firearms shooters need adjustable scope mounts more today than ever before. I think that’s because modern guns are being assembled faster and with less precision than they were in the past. The thing is that firearms shooters are not as aware of scope problems as airgunners, so they tend to have more of them; and when they do, the problems are harder for them to resolve. I’ve tried to help people who I knew were having some common problems such as adjusting too high in the scope’s range, but they just looked at me like I was crazy. Surely, no scope manufacturer would field a scope whose adjustments were not 100 percent useable?
That’s all I have for you today. How about telling me your other unresolved scope issues?
by Tom Gaylord, a.k.a. B.B. Pelletier
I don’t know about the rest of you, but this blog is teaching me things. I’m learning a lot more things by doing all these little tests and experiments than I ever learned by reading about airguns. Of course, that’s partly because there aren’t that many good books around, but it’s more because of the excellent discussions we have here. And more often than not, something really special comes from all this study.
Yesterday, I was finishing an article for my monthly column in Shotgun News when I happened to spot something interesting. I was writing about the Chinese KL-3B Fast Deer sidelever spring-piston air rifle and I showed two targets — one shot with RWS Hobby pellets at 10 meters and another shot with the same pellet at 25 yards. The 10-shot group at 10 meters measured 0.38 inches between centers, and the 10-shot group of the same pellet that was shot at 25 yards measured 1.918 inches. That was certainly a huge increase for just moving the target 14 yards farther! But it was more than that. I had seen something similar recently — something that really stuck in my mind.
Fast Deer sidelever rifle has a quality look, but the accuracy falls off fast after 10 meters.
Then I wrote something in the column that jogged my memory. I said the Fast Deer was acting like it was a smoothbore because it shot great at 10 meters but lousy at 25 yards. That was just how the Diana model 25 smoothbore had shot when I tested it last year! And that’s when it hit me. As I remembered it, it was performing EXACTLY like the Diana model 25 smoothbore!
The 1940 Diana model 25 smoothbore performed exactly like the Fast Deer air rifle.
So I looked it up, and I was right. With JSB Exact RS pellets the Diana 25 put 10 into 0.337 inches at 10 meters, and at 25 yards it put the same JSB Exact RS pellets into 2.421 inches after I played with the seating to find the best place.
Learning has occurred! I now know that I’m getting the same results from a gun with a rifled bore as I got from one that is a smoothbore. Or, to put it another way, the rifled gun shoots like the pellets aren’t being stabilized by the rifling. It shoots like a smoothbore.
Is the Fast Deer even rifled?
Then I wondered if the Fast Deer is really rifled. So, I ran 2 different pellets down the bore from muzzle to breech — have to go that way because the barrel is fixed. Both pellets (RWS Hobby and an old Tech Force Chinese pellet) showed good engraving around the bases of their skirts, but only one showed any contact with the pellet head. Unfortunately, the RWS Hobby that I’d used when testing the rifle did not have any marks on its head. Instead, it was the domed Tech Force pellet made years ago that had engraving. However, I never shot the Chinese pellet when testing the gun for accuracy. Pyramyd Air used to carry them, but they no longer do. The point is, they may solve the longer-range accuracy problem. If they don’t, I will look around for another fat .177 pellet that will.
So what we have is a Part 6 test coming up for the Fast Deer rifle. I said I would scope it and shoot it at 25 yards for Part 6, but if it doesn’t shoot accurately with open sights at 25 yards, that seems like a big waste of time.