Archive for April 2010

Recently I had a really nice and informative conversation with Mike Kurtz, technical guru, over at Hawke Optics ( He told me that well over 90% of their customer service issues have to do with scope owners improperly adjusting their scopes, and I found out that I have been doing some things wrong from time to time. Perhaps you have too, but before we get to that, let do a quick overview of how a scope works.

Take a look at the picture of the scope below. Light comes in through the big end (on the left) and is deflected down by lenses so that it will pass down the main tube of the scope (which in this case is a 30mm tube). As the light reaches the tube, the image is inverted by a lens.

The light then passes into the erector tube, which holds the crosshairs and is roughly in the vicinity of the elevation and windage knobs. The erector tube is fastened to the main body of the scope at the rear, but the front is free to move. When you adjust the elevation and windage knobs, you are moving the erector tube up and down, left and right, until the point of aim corresponds with the point of impact.

(A side note: theoretically, you could zero your scope in a single step at a given distance by clamping your airgun in a vice, firing a single shot, and then adjusting the scope so that the crosshairs intersect at the spot where the pellet hit.)

When the light comes out of the erector tube, it passes through another set of lenses, which flip the image back to right side up and focuses the image for the ocular lens where, you, the shooter, look through the scope.

Now, before we go any further, please notice this one key point: the erector section of the scope is a tube, and it lives within the outer chassis of the scope, which is also a tube. So the erector is a tube within a tube – got that?

The picture below shows an internal view of the scope as it comes from the factory with the outer chassis and the erector tube in perfect alignment, and the elevation turret and the windage turret are adjusted equally.

Okay, now let’s look at some ways folks get into trouble with scope adjustment. The picture below shows a scope that has been adjusted too far left. The erector tube is pinned against the wall of the outer chassis, and, as a result, the elevation adjustment is severely limited because there is no room for the erector tube to travel.

The picture below shows a scope that has been adjusted too far down and right, pinning the erector tube against the erector spring, the windage turret, and the outer chassis. Again, windage adjustment is very limited since there is little room for the erector tube to move.

Finally, below is a scope that has been adjusted too far up and right, and the erector spring has lost contact with the erector tube to support it. When this happens, the reticle free floats, and you will have point of impact issues. Mike tells me this is the most common of scope mounting issues.

So, how do you avoid these problems? First, don’t use up all of the adjustment in any direction with either the elevation or windage turret. Second, if you find yourself using up all of the adjustment, get yourself an adjustable mount. Put the scope back in optical center, then use the adjustments on the mount to get you pretty close to where you want to be zeroed, and use the elevation and windage adjustments on the scope to do the fine tuning.

Til next time, aim true and shoot straight.

– Jock Elliott

Recently, Crosman Corporation sent me a sample of its new Silhouette PCP Target Pistol (Model 1700P) for evaluation, and, to spare you any further suspense, I think it’s pretty neat.

The 1700P is a single-shot, .177 caliber precharged pneumatic air pistol that weighs 2.5 lbs and stretches 14.75 inches from end to end. The 1700P meets requirements for silhouette air pistol competition with both the International Handgun Metallic Silhouette Association and the National Rifle Association.

At the extreme back end of the receiver is the bolt, which comes from the factory hanging to the left so that right-handed shooters can cock and reload without taking their shooting hand off the grip, the bolt but can be switched to right hanging if the shooter prefers. Below that is a fitting at the rear of the receiver with a port through which adjustments can be made to the hammer spring and hammer stroke for velocity string tuning.

Below that is the ambidextrous pistol grip assembly with plastic grips on either side. These grips can be removed to a trigger weight adjustment (more about that later). Forward of the pistol grip is the cast metal trigger guard, inside of which is a die cast trigger that is adjustable for weight and over-travel and can accept an aftermarket trigger shoe. A push-button safety can be found between the trigger guard and the pistol grip.

Forward of the trigger guard, on the underside of the air reservoir, is a 3000 psi air gauge. At the end of the air reservoir is a snap-off plastic cap that protects a male foster fitting used to charge the 1700P. Above the snap-off cap is a black metal muzzle brake that also serves as a mount for a post-type front sight. (Originally, Crosman planned to mount a ported muzzle brake on this pistol, but the design engineers discovered this would violate IHMSA rules, so the plan was scrapped.)

Aft of that is the German-made Lothar Walter barrel which attaches to an anodized aircraft aluminum receiver that is fitted with 3/8 inch dovetails fore and aft of the breech. The breech has a .177 loading tray to make sliding pellets into the breech easier.

An important note: because silhouette shooters have so many varying preferences for sighting systems, the 1700P does not come with a rear sight or scope. Available extra-cost options include a William or LPA notch rear sight (favored by IHMSA Creedmoor style shooters) or a Williams peep sight (often used by standing silhouette shooters). In addition, this pistol may be easily fitted with a rifle scope, pistol scope, or red dot. Mine is shown below with the Williams notch rear sight.

To get the 1700P ready for shooting, charge it to 2900 psi with a high pressure tank or SCUBA tank. As it comes from the factory, the 1700P is set up to deliver 50+ shots from a fill, launching 7.9 gr. Crosman Premier pellets at 450 fps. I shot the pistol through my chronograph and found it was launching the 7.9 gr. pellets at 460 fps average. It takes about 35 pump strokes to refill the reservoir from 1700 psi to 3000 psi using a Benjamin HPP3k pump. If desired, the pistol can be tuned to shoot as fast as 550 fps, but with fewer shots per fill.

When I first tested the trigger on the 1700P, the first stage came out at1 lb 14 oz, and the second stage went off at 5 lb 13 oz, which is not so hot. So I removed the plastic pistol grips, ran the trigger weight adjustment up as high as it would go, and then dropped it back down to the lowest weight. With the next measurement, the second stage tripped and the shot went down range at a much more manageable 4 lbs.

Note: if you want to lighten the trigger by cutting coils off the trigger spring or polishing the trigger parts, you run the risk of voiding the warranty. Why? Because every air rifle and air pistol Crosman makes must pass the ASTM drop test. But if you modify the trigger in any way, it might not pass the test, and therefore Crosman accepts no responsibility.

I saved the best part for last: the accuracy of the 1700P is excellent. My pal, IHMSA champion Steve Ware is a steely-eyed pistol silhouette competitor. He clamped his 1700P into a vice and fired 5 shot groups at 18 yards. His best group, shot with H&N Finale Match pellets, measured just .071 inches ctc. No wonder Crosman claims this pistol will shoot quarter-inch groups at 30 meters.

In all, I find the Crosman 1700P to be an entirely worthy competition air pistol that delivers a whole lot of performance and accuracy at a price that is just a fraction of its high priced competitors.

Til next time, aim true and shoot straight.

– Jock Elliott

The British government very nearly put the lights out on the Brocock airgun company in 2004. The company, which had been famous for the manufacture of its “air cartridge” airguns, which were loaded with metallic cartridges that had been pressurized with air and loaded with a pellet, had been virtually wiped out by a change in British law.

On 20th January 2004, it became an offence to manufacture, sell, purchase, transfer or acquire any air weapon using a self-contained gas cartridge system, so Brocock could no longer make or sell the product that was at the heart of the most profitable part of its business. Then, in May 2004, it became an offence, punishable by a minimum of 5 years and a maximum of 10 years imprisonment, to even possess a self-contained gas cartridge weapon without the necessary firearm certificate.

But the Brocock folks are neither slackers nor dummies, so they rolled up their sleeves and got to work. One of the smartest things they did was to hire the chief designer for now-defunct Falcon Pneumatics. His charge was to create a new line of precharged pneumatic air rifles and pistols.

The second really smart thing they did was to design one really good basic action that would serve as a modular base for creating a whole line of air rifles and pistols. Starting from an excellent action, they could then swap barrels, reservoir sizes, and valving to produce a full product spectrum that would please a wide range of airgunners.

The new Brocock line of precharged air rifles and air pistols was launched in January, 2009, and the AIMX Atomic pistol is the latest model to fall into my hands. It is very similar to the Grand Prix, which I reviewed earlier, but that Atomic is fitted with front and rear sights.

The Atomic is about a foot long from the tip of the muzzle to the trailing edge of the rear sight or about 13.5 inches measured diagonally from the tip of the muzzle to the lowest rear edge of the pistol grip. Dangling from my Lyman digital trigger gauge, it weighs in at 2 lbs 12 oz.

It has an ambidextrous wooden “stock” with checkering on either side of the pistol grip. The stock overhangs the pistol grip at the rear by about an inch. The trigger guard, which is an integral part of the stock, is wood. The metal trigger is wide and slightly curved. Forward of the trigger guard a single Allen head bolt secures the receiver into the stock and the rest of the stock, which is flattened. flattened.

The air reservoir has a screw-off metal cap, and under that is a male foster fitting for charging the air reservoir from a SCUBA tank or hand pump. Above that is the .177 cal. Barrel which has a screw-off fitting for attaching a silencer where legal. On top of the muzzle end of the barrel is the fiber optic front sight which is surrounded by a cage of metal that protects the sight but also has cut-outs that allow light to reach the fiber optic rod.

In the middle of metal receiver is the opening for the breech. At the rear of the receiver is a metal notch rear sight which is adjustable for elevation and windage. On the right side of the rear section of the receiver, there is a lever, and at the very aft end of the receiver is a knurled knob. Like the Grand Prix, the fit and finish of the Atomic are excellent and very appealing.

Getting the Atomic ready for for shooting is easy. Remove the protective cap on the foster fitting and charge the reservoir to 200 bar/2900 psi. Press the lever at the rear of the receiver down, and the knurled knob springs backward, opening the breech. Pull the knurled knob backward until it clicks, and you have cocked the action. Insert a pellet into the breech, push the knob forward until it clicks to close the breech, and you’re set.

Now, here comes the really nice part: the Atomic has one of the nicest air pistol triggers I’ve shot in a while. At 9.4 oz, the first stage comes out of the trigger. At One pound 7.8 oz, the shot goes down range. It’s crisp and predictable. If you miss, it sure isn’t the trigger’s fault. Filled up to 200 bar, the Atomic will deliver 30 shots, launching JSB 8.44 pellets at an average of 540 fps, which is about 5.8 fp of energy at the muzzle.

At 13 yards from a Creedmoor position I found myself shooting small groups that probably would have been one-hole clusters if I had been using a scope. In all, I liked the Atomic a whole lot. It’s the kind of pistol that just begs an airgunner to take the UJ Challenge.

Til then, aim true and shoot straight.

– Jock Elliott

My rampant bookaholism is already known to the readers of this blog. I remain an unrepentant devotee of used bookstores because, like Jim Hawkins on Treasure Island, you never know what goodies you are going to unearth. Recently I scored on a stack of Peter Capstick volumes. Capstick was a professional hunter in Africa for many years, a frequent contributor to shooting and hunting magazines, and one of my very favorite authors of all time.

I was happily cruising through one of Capstick’s volumes entitled Last Horizons when I encountered some thoughts that might shed some light on the occasionally heated discussions of ballistics as pertains to airgun hunting that pop up from time to time on the online forums. It is a subject of great interest to me because, while I am not a frequent hunter, I am sometimes called on to do a pest control favor for a neighbor, and when that happens, I want a decisive, humane outcome.

In an article called “Use Just Enough Gun,” originally published in the Guns & Ammo Annual in 1976, Capstick said:

“It ain’t if you hit ‘em, it’s where you hit ‘em. Nothing counts like bullet placement, and if you expect to knock buffalo and elephant over with bullet energy, you’re in a for a rude and possibly fatal update in your thinking.”

Now, to be sure, Capstick was writing about hunting big game with large caliber rifles, but the principle remains the same even if you’re out to assassinate squirrels with your airgun: you have to hit the game where it counts, no matter what caliber you employ.

Capstick goes on in his inimitable way:

“It’s a sad fallacy of hunters unfamiliar and unpracticed with the cave-bore Magnums who have, mixed up somewhere in their awe of that great, gaping muzzle, the sure knowledge that all that is necessary for success is to hit meat and arrange of the taxidermy. I have been to some really nifty funerals that would refute that point.”

It’s probably a safe bet that none of the readers of this blog are likely to be trampled to death by a wounded ground squirrel or fatally gored by an enraged woodchuck, but just because you’re launching a large caliber pellet at your prey doesn’t mean you will automatically achieve the desired outcome.

Elsewhere in the book, Capstick says:

“Of course, many drop instantly to the shot, but only because of bullet damage to a vital spot such as brain, neck or spine.”

Capstick isn’t alone in this belief. One day I was googling “wound ballistics,” and I found It is a report by the FBI Academy Firearms Training Unit on “Handgun Wounding Factors and Effectiveness.”

Most handguns are, like airguns, pretty slow, so I was intrigued by the following:
“The human target can be reliably incapacitated only by disrupting or destroying the brain or upper spinal cord.”

A disclaimer: I am emphatically not interested in shooting people, but the principle still holds when hunting small game with an airgun: if you want an instant “lights out” shot, you have to disrupt the brain or upper spinal cord.

So it seems to me that there are four key factors in successful airgun hunting (beyond the bushcraft of finding and stalking your prey):

• an accurate weapon capable of hitting the brain or upper spinal cord at the range at which the shot will be taken,
• enough power to disrupt the brain or upper spinal cord,
• the patience to wait for the right shot to be taken, and
• an adequate knowledge of the anatomy of your prey so that you can aim at vital areas.

Having said that, Cliff Tharpe, producer of Airgun Hunting the California Ground Squirrel, observes that as he goes up in caliber, he sees more “bang-flop.” In other words, a larger pellet, properly placed, is more likely to produce instant lights-out.

Til next time, aim true and shoot straight.

– Jock Elliott

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