Archive for February 2008
by B.B. Pelletier
The term ACCURIZED is so common in airgunning that people use it without thinking. What does it mean?
As far as I can tell, Robert Law of Air Rifle Headquarters (ARH) was the first to use the term ACCURIZE in relation to airguns. You would think that he had a specific definition in mind, but when you read what he wrote in his Fall/Winter 1979 catalog to describe the term, you’ll see it doesn’t seem to amount to much.
“Accurization involves having a highly trained specialist totally disassemble a gun. Each individual part is cleaned and inspected. The ultimate space-age lubricant or bonded coating is then applied to each component for optimum performance and friction reduction. This stabilizes the cylinder compression mechanism and greatly reduces normal wear. Both accuracy and velocity improve. Recoil is often reduced by as much as 60 percent.”
That is the only paragraph out of four under the heading Optional Accurization that has any technical information in it, and, as you can see, what is there is pretty thin. It sounded good to me when I read it for the first time in 1979, but now that I’ve tuned a few guns, it doesn’t hold much water. However, let’s not stop there.
I have encountered the results of an ARH “Optional Accurization” and can report to you what I found. A friend acquired an FWB 124 that wasn’t performing well and asked me to overhaul it for him. It had been accurized by ARH and not touched since. When I removed the action from the stock, I was shocked by the large amount of what looked like moly grease that had escaped the cocking slot and was now coating the outer surface of the spring tube. I scraped about a teaspoon of this gray viscous grease from the outside of the spring tube around the cocking slot, which told me to expect many times more inside the tube.
There was more, but not as much as I feared. The grease had been slowly migrating outside through the cocking slot, so I found a couple more teaspoonfuls inside, but no more. I was curious why this rifle was so loaded with grease, and the answer surfaced in an ARH pamphlet about accurizing FWB 124s. The instructions advised the use of Moly G powder everywhere on the inside of the 124 action except on parts relating to the trigger. They go on to say that an entire jar of Mainspring Dampening Compound should be spread on the mainspring. The ARH jar of Mainspring Dampening Compound held 1/2 oz. of thick white silicone grease. That’s about four teaspoons full.
Inside the gun, the lubrication (grease) had moved to the cylinder walls, so the mainspring was free to move. However, if it tried to wiggle against the cylinder walls it came in contact with this thick grease that dampened its vibrations. Over the course of the years, all the dark Moly G powder had mixed with the Mainspring Dampening Compound until what remained looked like a thick gray grease.
Before my tuneup, this rifle was shooting Crosman Premier 7.9-grain pellets around 730-750 f.p.s. After I tuned it up and switched out the mainspring and seal, it shot 960 with the same pellet.
The velocity reported in the preceeding paragraph is in error. The final velocity wasn’t 960 f.p.s., it was 861 f.p.s. A reader of this blog named Lance pointed this out to me and I found the report in the November 1997 issue of The Airgun Letter. I apologize for this mistake.
Mainspring Dampening Compound was good stuff back in the 1970s, when factory mainsprings were loose both inside the pistons and on the spring guides. By the mid-1990s, tuners such as Ivan Hancock and Jim Maccari were telling everyone that the physical tolerances inside spring guns had to be made tighter and the lubrication had to be minimal. Hancock coated certain of his springs with a permanent black substance that I referred to in The Airgun Letter as Black Tar, a term that caught on. Maccari soon came out with a different black tarry grease that home tuners could apply, and, because it didn’t rob velocity when done correctly (like the old Mainspring Dampening Compound had) he dubbed it Velocity Tar.
By the 1990s, most airguns in the higher-powered class were also using synthetic seals instead of leather. Let me tell you what that means. A tuned RWS Diana 45 with a leather seal can make about 840 f.p.s. with a light .177 pellet. With the same pellet in the same rifle converted to a synthetic seal, the velocity rises to the high to mid-900s. Before you start thinking about replacing leather seals with synthetic, however, know that most airguns will require a new piston for the synthetic seal – it’s not a straight swap. Those guns that do have the leather seals are starting to have some collector value. I once converted an HW55 from a leather seal to synthetic and now I wish I hadn’t, because with leather the gun is a better collectible.
At Beeman, the term was a “Super Tune-Up.” I won’t say that what they did was essentially the same as the ARH accurization, because I don’t believe they ever used Mainspring Dampening Compound (which they also sold) to the same extent. Also, they were in business later, so they had some tunes like the Laser Tune that were far more modern than those done by ARH. A laserization involved a fitted piston seal, a mainspring that was easier to cock and a new gold lubricant called Laser Lube. Together, these things boosted the R1′s velocity up to 1,100 f.p.s.
At ARH the term accurization was used loosely, and the procedures to do one probably evolved as time passed. Nobody would want a 1970s tune on their gun today. A 1976 FWB 124 got about 820 f.p.s. when tuned to the max, and the 124 has always had a synthetic seal. It also vibrated a little after tuning. With a good tune today, it’s possible for the same rifle to reach 960 f.p.s. with the same pellet and be almost dead calm.
The bottom line to this report is that accurization is a nebulous term with no foundation in fact. It is about as descriptive as the term “Magnum,” which used to mean an airgun that could shoot faster than 800 f.p.s., but today means faster that 1,000 f.p.s. In 10 years, who knows what it will mean?
by B.B. Pelletier
Okay, today I’d like to finish this report. There’s a lot to cover, but I won’t go into detail like I did in the first two parts. Remember, the complaint was a point-of-impact shift from one day to another AND a shift in the middle of a shot string. Those two separate reasons could each cause a POI shift, but if BOTH of them are happening, it can only be caused by parallax or a broken scope or loose mount. I think Hegshen is careful enough to catch the bad scope and loose mount, so I had to go with parallax. But there are other causes of impact shift.
Cause 1. Positioning of the cocking knob
This is an AirForce quirk, because they have a cocking knob that must be rotated into one of two locking notches on either side of the receiver. Fail to do it, and the bolt will move during firing, causing drastic changes in the amount of compressed air that gets behind the pellet. That will cause inaccuracy and POI shifts. When I was at AirForce and answered phone calls about accuracy problems, this was one of the main causes of those problems. AirForce made a video about how to operate the rifle and put the instructions in the owner’s manual. If a shooter didn’t pay attention to those instructions, they often had accuracy problems. Some guys went to the extreme of looping a rubber band around the bolt handle and the gun, so the handle would always be pulled into the notch when not being used to cock and load the gun.
Cause 2. Elevation adjusted too high
When the scope’s internal elevation is adjusted up beyond a certain point, the erector tube return spring relaxes to the point that the tube can move at will. This will cause a wandering POI or sometimes a jump from one POI to another. This is a universal problem with scopes and the principal reason I recommend B-Square adjustable mounts. You can usually feel when the spring tension relaxes, because the clicks become softer and mushier. Avoid this region of adjustment if you want accuracy and a consistent POI.
Cause 3. Temperature change
A large change in outside temperature will change how the lenses in your scope are aligned. This is usually a cause for a POI shift when more than a day lapses between shooting, but I once saw it happen in the middle of a field target match, when a thunderstorm dropped the temperature by more than 20 degrees in a short time. The only solution is to re-zero the scope.
Cause 4. Shooting at different ranges
I tried to make this point in Part 2, but if that wasn’t positive enough, I’m saying it again. Shooting at different ranges affects the zero of your scope. I’m not talking about elevation. Everyone knows pellets don’t fly straight and will print at different places depending on the range. But if the scope is not aligned with the bore of the airgun horizontally, it will shoot to one side close up and to the other side far away. You will never see this after zeroing, because you will have aligned the scope and pellet flight path at one specific range. But, change ranges, and the POI will shift to the side. When the scope is optically aligned with the bore, this won’t happen.
That being said, this one isn’t a big problem for most scope users. When you miss your POI on a deer, you’re still within the kill zone and no one is the wiser. It’s only when you’re looking for half-pellet diameter accuracy and get slapped in the face with a one-inch shift that you pay attention.
Cause 5. Cant
Cant means tilting the scope away from the plane at which it was sighted-in. This will throw the pellet to the side and also down. I did a cant test that demonstrated a pellet movement of as much as 6 inches at 50 yards when cant is involved. For that test, the cant was a measured 20 degrees in each direction, something that would never happen in the real world. But a 3-degree cant is possible for some people on some terrain that doesn’t give good cues as to level. That can throw you off by an inch at 50 yards.
Cause 6. Sidewind
A sidewind will blow your pellet in the direction the wind is blowing, and also either up of down, depending on the wind direction and the direction of spin imparted by your barrel. This is caused by a phenomenon known as precession. A gyroscope (your spinning pellet) that’s pushed in a certain direction will move at 90 degrees to the force. The movement will always be in the direction of spin. If the gyro is spinning in a righthand direction and you push it to the right, it doesn’t go right…it goes down. Push from the left and the same gyro doesn’t go left…it goes up. The gyroscope is touching the earth at its point where a lot of friction holds it fast. But a pellet flying through the air has no friction holding it in place, so it tends to go with the flow. Therefore, the sideways movement is usually larger than the upward or downward movement.
Cause 7. Changing the scope’s power
When the power is increased or decreased on some variable scopes, the point of impact can change. Apparently, it depends on how the lenses are arranged inside the scope. This used to be a common problem, but a lot of scope manufacturers have designed their scopes so it doesn’t happen as much anymore. I shoot a lot of Leapers scopes, and I’ve never seen a POI change when the power was adjusted on one of them.
Those are all the causes for POI shift I can think of. If you know of one I’ve overlooked, please respond.
by B.B. Pelletier
Collectors, there is an estate sale going on right now on the internet. Many of the guns have already been sold, but there are still a few choice items left. Also, there’s a treasure trove of old airgun literature, including a rare first edition Beeman catalog. The site says estate auction, but what you do is make an offer to them. If they find it acceptable, they contact you, and you buy the gun or whatever.
There is more than what’s listed. All the rifles are listed, but there are a couple of air pistols and a lot more literature than what you see on the site. Be sure to use the scroll bar and to click on the other links on the left side of the page. The former owner passed away a few years ago and his brother is helping the widow sell the items. I’ve already had a transaction with them and everything went well. Be sure to ask about condition because the photos do not show detail.
The family is having more difficulties right now, so it may take a while for someone to get back to you. Just be patient.
The best of the best
Today, we’ll look at what many people believe to be the highest pinnacle in airgunning – the Olympic target rifle. When I got back into airgunning in 1976, these rifles were selling for $500-700. Today, they push $3,000.
Fortunately, for those who don’t have trust funds, there’s a dynamic in 10-meter rifles and pistols that exists nowhere else in airgunning – planned obsolescence! Every few years, some new technology comes along and carries the majority of world-class shooters along to the next level. Many of them are sponsored and don’t buy their guns to begin with; but once the movement starts, there’s no stopping it. What it leaves behind is a host of deeply discounted, slightly out-of-date rifles, any of which could still win gold. I’ll talk about used rifles in a different post, because today I want to concentrate on the state of the art.
Ergonomics – the top feature today
Without a doubt, the man-machine interface is what sets today’s 10-meter guns apart. Since the 1960s, these guns have been improving in this area, but in the late 1990s they underwent a total transformation. Nearly everything that can be adjusted on the guns is now movable so it can adapt to whatever body configuration and shooting style might be desired. The only area yet to be optimized is those shooters with disabilities, and that’s because each disability is unique. But, for able-bodied shooters, the new rifles offer near-perfect fit.
About 10 years ago, two top airgun makers pioneered a way of canceling the slight movement that’s transmitted when the gun fires. Newton’s third law of motion cannot be ignored, and for every action there is an equal and opposite reaction. Shooters call this recoil. The amount of recoil depends on the mass of the object being acted upon, and in a 10-meter target rifle, that’s a .177 caliber pellet weighing about 8.5 grains. That mass is accelerated to a given velocity by a certain amount of force. The rifle reacts to the movement of the pellet by moving in the opposite direction with the same force. The force that pushes an 8-grain pellet to 580 f.p.s. doesn’t do much when it encounters a rifle that weighs 75,600 grains. In fact, as far as most people are concerned, there’s no movement at all. To a person who can detect a movement as small as 0.01″ while looking through precision sights, the reactive motion is present and significant. So, something was done.
In one system, a small weight inside the gun’s action is pushed backwards with the same force that pushes the pellet forward. It travels for a short distance expending the minimal energy and the shooter never feels anything. I’ve shot rifles and pistols equipped with this technology, and the only clue you have that the gun fires is the sound it makes. There’s not so much as a pulse of feeling when the gun fires! It makes an IZH 46M feel like a .22 rimfire in comparison.
I would have guessed that sights had progressed as far as they could go back in the 1970s, but they’ve kept pace with the new guns. Sights don’t change as rapidly as rifles; they’re on an advancement schedule of every 10-15 years, as opposed to every 5-10 years. And, unlike the guns, they aren’t always abandoned when something new comes along. I have sight components, like a Gehman variable diopter and a set of graduated transparent front apertures, that I move from gun to gun. The Gehman design is over 40 years old, and the front apertures are at least 15 years old. Today, several front sights have the same feature by pressing an o-ring between two pieces of plexiglass. The o-ring fattens and thins based on the pressure.
Walther rifles fill to 300 bar (4350 psi). All others that I’m aware of fill to 200 bar, which is more common worldwide. Walther gets more shots from this higher fill pressure, but the lack of fill equipment, especially in the U.S., limits shooters. The guns will function with a lower-pressure fill, but total shots are fewer.
Specifications of a top 10-meter rifle
A top 10-meter rifle today is extremely ergonomic, with an aluminum subframe to which everything is attached. It has stabilization in some form. It is a PCP.
Acceptable specifications for competition
You can compete without the stabilization and even without the ergonomics. You should use either compressed air or have a single-stroke pneumatic action. The sights must be world-class but do not have to be the latest models.
I sense you readers want to know more about these rifles. Please tell me in your remarks what it is you’d like to know. In the next installment, I’ll talk about things like triggers, power and how it has declined over the years, the progression of powerplants through time (1965 to now) and accuracy.
by B.B. Pelletier
Before I begin, I’m going to break my rule about commenting on forums. I read a thread about me on the Yellow Forum yesterday and was surprised to see some very complimentary remarks. I usually don’t get that. Several who commented also mentioned that they don’t agree with me all the time, and I’d like to say here and now – NEITHER DO I! I have changed my mind many times in the pursuit of this hobby and I bet I’m not done, yet. Just a few weeks ago I discovered a new wrinkle on the artillery hold that makes it work a lot better than the way I described it in the Beeman R1 book.
I’m not fishing for compliments, but I’d like to thank everyone who added to that thread.
Okay, to the task at hand. Our bore is clean, so let’s mount the scope and get to testing. With an AirForce Condor, however, there are some other things that should be checked. Barrel tightness is an important one. Four screws hold the barrel in the Condor, and if it’s a recent one the screws go through the bushings to contact the barrel. Older Condors have two long screws that contact the barrel and two short screws that contact the barrel bushings.
The other thing I checked was the clearance of the top hat. It’s set at the factory at 0.090″ clearance, and should be left there for best results. This one was okay. Then, I mounted the scope and tightened it down. I used an AirForce 4-16×50 scope I use on both my AirForce rifles. It’s in a prototype B-Square adjustable one-piece mount with ultra-high riser blocks. It provides too much elevation, but it works on every AirForce rifle I try it on, so scope mounting takes about one minutes. Time is money. Let’s shoot!
Shooting from the bench
I promised someone I would report about shooting techniques from a bench rest, so you probably think I have a high-tech bench to use in testing. Nothing could be further from the truth. My “bench” is a rickety folding table I drag from range to range. It’s a TV table on steroids. When I shoot PCPs, I use a long shooting bag filled with crushed walnut shells. The top is arranged in a “V” and the rifle lays between the upright legs. A slender Condor fits this bag perfectly.
Sight-in at 10 feet
If you haven’t read my Sight-in article, I recommend you do so now. You don’t need boresighters, lasers or any other gimmicks to sight in an airgun. Just start shooting at 10 feet. Your goal is to get the pellet printing as far below the aimpoint as the center of the scope is above the center of the bore. Of course, you want to be aligned with the aimpoint vertically. The picture shows this much better than I can explain. Remember, this is shot at 10 feet. Because of the terrain on this range I had to shoot at 12 feet. Everything worked as it should.
Move to 20 yards
After you’re on at 10 feet, move to a target 20 yards away. Refine the sight adjustments until you’re on at that distance. This takes another 5 minutes (took three shots). On to 35 yards, because that was the distance at which Hegshen complained of point-of-aim shifts of 1-1.5 inches.
Move to 35 yards
At 35 yards, I started shooting JSB Exact 15.8-grain domed pellets with the power wheel on No. 4. On my Condor, that’s where I get great accuracy. But not on Hegshen’s rifle. The pellets were all over the place. His rifle has the latest valve (we checked it before I started this test), and we filled the air tank to 3,100 psi. After all the shooting I’d done to this point, the gun was probably down to 2,800-3,000 psi or so.
When pellets are all over the place and seem to be moving slowly (as these did), I turn up the power. In this case, I went to power setting No. 8. The point of impact climbed several inches, which was perfect, because I didn’t want to destroy the aimpoint.
This time, the pellets went to the same place, so I shot 20 rounds to see if there would be a point-of-impact shift. There was none. From this test, I know the rifle isn’t shifting its point of impact, so now we can move on to more likely culprits.
Before we move on, a word about this 20-shot group. It’s not a five-shot group. Had it been, it would have been about 0.30″ center-to-center. But, shoot 10 shots and that’ll increase to 0.70″. Shoot 20 shots and it increases again. The group that you see measures 1.124″ c-t-c. Could this rifle have done better had I shot a second 20-shot group? Of course. Could it have done worse? Absolutely. Don’t get hung up on the group size, because it doesn’t matter. Look at the shape. There is no POI shifting going on, and that’s all we care about today.
Okay, the rifle is fine, so AirForce packaged it up and sent it back to Hegshen, along with the 35-yard target that I wrote some notes on. What if he still has the point-of-impact shift when he gets the rifle back?
I’m pretty sure he will, because I know what’s happening. When I was the technical director at AirForce, I took all the phone calls and emails about POI shifts and accuracy problems, and I have seen this happen many times before. Before I tell you what it is, let’s review this case. Hegshen told me he would get his rifle sighted-in, then come back to it several days later and the point of impact would have shifted. He also said that sometimes he would shoot five or six shots and then the point of impact would shift 1-1.5 inches to the left at 35 yards. He also told me his rifle shot to one side close up and to the other side far away. What’s wrong?
Look at the picture of me shooting the rifle. See how high my head is above the bore of the rifle? It has to be high because that’s where the scope is. If I do not put my face at the same point on the buttstock every time I shoot, my point of impact will shift, too. I’ve had to learn how to position my head in the same place shot after shot, or my POI would shift, too. But that’s not all.
Look at where the center of the 35-yard, 20-shot group is. Now look at where the first 35-yard group of shots with the lower power setting is. It’s several inches lower and slightly to the right. In other words, changing the power changes the point of impact. And, changing where you position your head changes the point of impact.
It’s difficult to see, but just in front of the scope on this rifle you can see a scope level. If you go back to Part 1 and look at the first picture, you can see it there, too. Hegshen has glued it to his rifle, which isn’t the best way to mount a level, but it works. I used that level on every shot to get the 20-shot group. Had I not, there would either have been point-of-impact changes or a larger group.
Here is what I’m telling Hegshen – and anyone else who experiences point-of-impact shift. First of all, the first shot from a cold rifle will probably not go to the same place as the shots that follow. That’s true for springers, for CO2 guns and for PCPs. It’s even true for firearms. Airgun barrels do not warm up as the guns are shot, but the valve of a PCP needs to be exercised occasionally to deliver consistent performance.
Second, you have to work on your hold, so your eye always ends up in the same place relative to the scope. This takes a lot of practice, but it returns more consistent groups.
Third, find a power setting and a single pellet and stick with both. Every time you adjust the power, you’ll have to sight-in the rifle all over again. Hegshen has been shooting Kodiaks, which are good pellets, but I recommend that he try JSB Exacts and Crosman Premiers. Both will outshoot Kodiaks in a Condor, as long as the power isn’t turned up all the way.
Fourth, if you want your groups to move straight up and down instead of from one side of the vertical reticle to the other, center your scope optically. Don’t take shortcuts. Do the labor and you’ll get the reward.
I’m not finished with this report, yet. There’ll be another part that covers all the other reasons for POI shift. But that will be another day.
by B.B. Pelletier
In last week’s report about Crosman pellets, I received two comments on how to properly lubricate pellets. If two people asked, there are 40 more in the wings waiting to hear the answer.
When to lubricate
Before we know how to lube pellets, let’s learn when it’s needed. I already mentioned that Crosman pellets are hardened with antimony, causing them to smear lead when driven to higher velocities. In truth, this can be anything above maybe 750 f.p.s., depending on the smoothness of the barrel they pass through. When the velocity moves above 850-900 f.p.s., the leading becomes almost a certainty in just about any gun. In spring-piston guns, every time the gun fires, the piston blows a tiny amount of oil vapor into the barrel. This oil is cumulative and thus keeps the barrel lightly lubricated. So, unless the gun has been tuned with moly and has no chamber oil in it, it doesn’t need to be oiled.
PCPs do not have an equivalent oiling function. They don’t blow any oil out when fired. CO2, however, can. If you lubricate the tip of each new CO2 cartridge with Pellgunoil, a tiny amount blows through the gun and out into the barrel. A multi-pump pneumatic will do the same, if the pump head is kept lubricated. A PCP blows no oil into the barrel…just dry air. So, PCPs, in general, can stand some kind of lubricant on their pellets at all velocities above 750 f.p.s. (approx.). Below that velocity, the lubricity of the lead takes care of things. So, no need to oil pellets for 10-meter guns.
What to use
I’ve covered this in several other places, but it here goes once again. I use Whiscombe Honey. It’s an oil mixture told to me by John Whiscombe, though I recently learned that he may not have discovered it. Apparently black powder shooters also use this stuff on their patches. Mix two-thirds Hoppes Gun Oil with one-third STP Engine Treatment by volume. Mix them thoroughly, and they’ll never separate. I store mine in a plastic squeeze bottle designed to hold fluids like oil.
You can use other things besides this. In fact, the 1990s were filled with tales of comical mixtures that airgunners traded like love potions, in the hope that the right one would give better accuracy, higher velocity or, who knows, smarter children. One UK company still makes a concoction they claim will increase velocity AND accuracy! I tested their claims and found no truth in them (surprise!). All you want from pellet oil is pellets that don’t lead the bore. Here are a few other commercial products that I know work:
I guess the sky’s the limit when it comes to pellet lubes. I like mine best for a very simple reason – SCOTT298, ARE YOU LISTENING?
The name of my lube is Whiscombe Honey. Now, what kind of airguns does John Whiscombe make? Springers – right? And not just any springers either – the most powerful springers on the market. And, yet, here he is recommending a petroleum-based product to go into a spring gun, where we all know it will lead to detonations. Right?
Whiscombe Honey doesn’t detonate if used as I am going to describe. At least I haven’t had a detonation yet, and I’ve been using it for a long time. The STP probably does the trick.
Take an old empty pellet tin. A .22-caliber tin works best because it’s deeper. Cut some good foam for the bottom of the tin. Real airgunners will cut the foam from one of the two foam pads found in every cardboard box of Crosman Premiers. Insert the foam into the tin and press it to the bottom. Put about 20 drops of your chosen oil on the foam, then cover the foam with a single layer of pellets.
When I competed in field target, I used to weigh all my Crosman Premier heavies and use only those from a specific weight group (weighed to the nearest tenth of a grain). These I loaded into a tin set up to oil the pellets. By spreading a single layer of pellets on the foam, they’ll roll around as the tin is carried, thus transferring the oil to the OUTSIDE of all pellets equally. How much oil pellets need varies with who does the telling, but I have found that a light coat is all it takes. When your fingers become oily from handling the pellets, that’s enough.
You probably expect increased velocity from oiled pellets, but that’s not what happens. They will either shoot at the same speed as dry pellets or the velocity will drop a little. Oil works well on relatively slow-moving objects such as lawnmower engines and door hinges, but on high-speed objects like pellets the surface tension can increase friction. That’s one reason that claims that any oil-based product can increase velocity are false.
Well, that’s the skinny on oiling pellets. I hope it helps.
by B.B. Pelletier
Before I start, Pyramyd Air is closing out the Walther RedStorm pistol and is offering them at a terrific savings. This will be your last time to get this pistol.
This will be a series that explores one of the most interesting and confusing conundrums of airgunning – the point of impact shift. I hear about it frequently and the complaint sounds like this. “I get my rifle sighted in, then come back to it in a day or so, only to find that the point of impact has shifted. If I sight-in again, when I come back to the gun, the POI has shifted once more. The gun is very accurate, but why can’t I keep the groups in the same place?”
Here is a second variation of this same theme. “I’ll shoot a group of several shots and then suddenly the gun throws two or three shots wide of the group. Sometimes if I continue the shots will go back to the first group but other times, the new POI is where all the pellets will land.”
I actually did a report on the problems of scope shift that you might want to read, though this series will be detailed in far greater depth.
This series is prompted by a reader comment that came in while I was at the SHOT Show. Hegshen said “I own an AirForce Condor and have been experiencing POI shifts that I can’t solve. I’ve tried everything and have sent my rifle back to AF for them to inspect.
Hegshen and I then had a lengthy discussion about his problem, which you can read in the comments section of the third installment of the Benjamin Discovery report. Normally I would play 20 questions with the person until something I said triggered the right neurons and he did something that corrected the situation. But this time was different.
I happened to be at the AirForce plant testing the final prototype of the new Diana scope base (it works well, by the way), and I asked if they had any guns in for repair. They had two, and one of them was from a guy with the same problem as Hegshen, so I knew I had found his gun. This time, I figured I would test the problem rifle myself, and see first-hand if the gun was shifting its POI. What’s more, I would document the entire process so you could see what I go through when analyzing a problem like this one. POI shift is one of the most common problems airgunners have today, so what we do here should really help a lot of you.
Step one – clean the barrel!
I did all the repairs at AirForce when I worked there, and whenever guns came in with complaints of poor accuracy, I always cleaned the barrel first thing. Of all the guns I ever tested for accuracy, I only found one barrel that was bad. It had a poor choke and I couldn’t get it to shoot no matter what I did. But dozens of other rifles shot perfectly. I didn’t take the time to test a rifle before cleaning because no one cares what it was doing before it got fixed and time is money. So, cleaning the barrel is always the first step, unless the barrel cannot be cleaned due to gun construction.
I’ve already described how to clean a barrel, and there are several posts in which I list the materials and steps to do the job right, but this time I took pictures to show you what I’m talking about. Here we go.
The cleaning rod and brush meet with a lot of resistance when I first try to push them through the bore. Part of this – maybe most of it – is due to the friction of the brand new brush, and some is due to the crud in the barrel. I don’t know until the session is over – after the brush has passed through the length of the barrel 20 times in both directions – how dirty the barrel really is. A lot of dirt and some lead flakes usually come out of the barrel.
Stroke after stroke, the brush is passed through the length of the barrel. Whenever possible, I try to hold the Dewey cleaning rod by the ball bearing handle to let the rod rotate and the brush to follow the rifling. However, for the first 14 strokes, there’s too much resistance in this particular barrel to allow that. Either this was a very dirty barrel or this brush was very large.
Following the cleaning, the rod is wiped clean and the brush is exchanged for a cleaning jag. Clean dry patches are then pushed through the bore in one direction, only (breech to muzzle). Continue pushing clean dry patches through until the come out clean. In this case, I was having difficulty getting the final residue out of the bore, so I wet a patch with Otis bore cleaner and pushed it through to soften the residue. The job was easier to finish after that.
Now that the barrel is clean, I’ll mount the scope and start testing next time.
by B.B. Pelletier
Before I begin today, I must retract something I recently said. Several days ago, I showed you a photo of the new Crosman Outdoorsman 2250XE I saw at the SHOT Show. I told you the pistol would be sold only by Crosman, through their Custom Shop. That was incorrect. In fact, Pyramyd Air is proud to now offer the Outdoorsman 2250 XE in their Crosman lineup. I also got it in my head that it was a pistol with a shoulder stock. It’s not…it’s a rifle. It’ll be available in .22 caliber when it reaches Pyramyd Air the beginning of March. I don’t know how many they’ll get, but one look at that custom skeleton stock suggests these will be in short supply. I’m sorry I led you astray with my prediction.
Many of our readers are relatively new to airgunning and don’t remember the stuff we went through over the past 50 years. So, when I start talking about “pure” lead pellets as opposed to hard lead pellets, I get a lot of questions. I don’t mind the questions, but in the case of pellets I’d like you to know some of what has happened over the past half-century, so you can appreciate what we have today.
Going back to the 1960s, the airguns we had in the U.S. were primitive compared to today’s standards. Those were the days of the “Benjamin Franklin” guns and also the days of Sheridan and Crosman. Manufacturers were starting to experiment with materials and finishes, and we all lamented the loss of the blued steel, nickelplating and wood that was traded for painted metal, cast metal and plastic. In the U.S., we were unaware (for the most part) of the fine European spring rifles and pistols made by Weihrauch, BSF and Diana. Air Rifle Headquarters was just beginning to explore that world in 1963, and it wouldn’t become widely known until Robert Beeman lent his golden touch in 1974. We were also unaware of the pellets that the European companies were just beginning to make – pellets that would redefine the accuracy of airguns in time.
This was also the time when some companies such as Crosman were starting to make repeating pellet guns. Some, like the Single-Action Six, were of conventional design, while others, like the model 600 pistol, were far ahead of their time. And, the pellets Crosman made for these guns were responsible, in part, for their mediocre level of performance at that point in time, just as were the leaky CO2 cartridges of that era.
Super Pells – flying ashcans
The pellets in question were called Crosman Super Pells during this time, and they came in red and black tins that resembled spice tins. Later in the ’70s, the boxes were changed to a long plastic tube with a square section, but the pellets inside remained the same. They were, in fact, the same pellets Crosman had made on the same machinery since production began in the 1920s! Over the course of 60 years, the pellet-making machinery wore out and the shape of the pellets morphed from a traditional wasp-waisted diabolo into a lead cylinder with barely the hint of a waist – not too dissimilar from aging Hollywood starlets. It was those rough cylinders – we called them flying ashcans – that I shot from all my Crosman airguns of 1958 until 1990.
Those pellets were also made of pure lead, which made them easier to form but far more prone to damage during handling. In fact, in those days, you were lucky if a pellet started out round at the base. We took it on faith that the blast of air or CO2 would swage out the pellet skirt into the barrel walls, making it uniform, but I know now that probably didn’t happen outside of the few spring-piston guns that existed.
Being soft lead and prone to deform, those old Super Pells didn’t want to feed through repeating mechanisms. They were okay for revolvers like the SA-6 and the 38T and 38C; but in a 10-shot semiauto 600, they tended to jam the mechanism. We blamed the guns, because there weren’t a lot of choices when it came to pellets in those days. Only Crosman and Benjamin brands were popularly available, and the Benjamins, while more like a conventional diabolo, were just as out-of-round, misshapen and prone to deforming.
So fine repeating semiautos like the 600 and the 451 languished, because the powerlets all leaked and the pellets jammed the mechanisms. Imagine our surprise to rediscover these fine guns in the 1990s, when we learned they were accurate, powerful and very reliable when fed good pellets!
Quick to oxidize
Another flaw the older pellets had was oxidation. Within a year or two, they would start to accumulate a dusty white coat of lead oxide if left exposed. Benjamin pellets came coated with thick oil and they oxidized, too. Today’s pellets have either an oil, wax or graphite coating that resists oxidation for a lot longer, though they do cause airgunners to think their bores are dirty when the compound scrapes off.
I believe Crosman’s investment in repeaters caused them to think about hardening the lead in their pellets when they came out with their new line of pellets at the end of the 1980s. Premiers are not the only pellet that’s made from hardened lead – the entire Crosman lead pellet line is hardened with antimony. As a result, they deform less and feed better through mechanisms than soft lead pellets. However, they also deposit lead in the barrel at lower velocities than pure lead pellets. That’s a drawback. The repeaters Crosman makes are all low velocity and aren’t bothered by it, but when Premiers are shot from magnum guns at high velocities, they need to be lubricated or they’ll lead the bore.
The change was worth it
Today’s Crosman pellets are light-years beyond the Super Pells of the past. Believe me, you wouldn’t want to go back to those times! The cheapest Chinese pellets are better than what we used to get from Crosman. However, today’s Crosman pellets are world-class in many respects. They represent a great value and the Premiers in the cardboard box are among the most accurate pellets available.