A Scope-Mounting System for .22 Rimfire Semi-Auto Handguns

Recently, I began a series of accuracy tests involving four .22 LR semi-automatic handguns. All four handguns had barrels just over 6 inches in length, and all had open sights. Each displayed excellent accuracy with open sights, but I wanted to see just how well these guns would shoot using some of the better match ammunition as well as standard-velocity bullets.

I didn’t see any available commercial scope-mounting system to fit my needs, so I used a bit of innovation; I designed away to scope these miniature guns with items readily available to me or those I could make up. Here’s how I did it: Preparing the Parts Though the method may be quite unique, the system turned out even better than I had anticipated. I simply 22 LR semi-automatic handguns were scoped using the mounting system described in the text.

From the top area Browning Challenger (made in Belgium) with 6-3/4-inch barrel, a High-standard Model 103 Supermatic Tournament with 6-3/4-inch heavy barrel, a Ruger Mark II Government Target with a 6-7/8-inch heavy-barrel, and a Highstandard Model 101 Duramatic with 6-1/2-inch standard-weight barrel. made an adapter to join two pairs of Conetrol horizontal split rings (www. conetrol.com; In normal usage, Conetrol scope rings are designed to fit into a rifle receiver scope base, and are retained by two laterally opposing cone-point jam screws.

These scope-ring studs are very short and can be reversed and attached closely together, utilizing a special adapter. I used the Conetrol principle of ring attachment by making an adapter to accept the ring-base studs facing one another. In this way, one pair of rings would surround the scope and the other inverted pair of rings would surround the barrel with the special interfacing adapter between them.

Scope eye relief really didn’t have to be perfect, and I wanted to use a small scope for the job to keep things in proportion. Here I used one of the older Redfield 4X Sportster scopes with a 3/4-inch tube. These small scopes were made for .22 rimfire rifles and looked right in place atop a small handgun. Matching things up would involve making split shims to adapt each barrel to the respective lower scope ring, as well as to the scope tube. This was easily accomplished using some 1-inch-diameter round nylon stock.

Then I drilled, bored, and split the shims, which didn’t take much time. It’s only necessary

22-caliber semi-auto handguns. The cone-pointed jam screws secure the rings to the adapter for a sturdy in-line mounting system. 22 LR semi-auto. to determine the barrel size at the scope-mounting position and make up the shims. Boring or drilling the parts is quite basic. I then made the ring adapters using shaped blocks of stainless steel.

I bored a 0.437-inch hole through the stainless block, which provided sufficient clearance so the two scopering studs would be just short of contact as they were placed into the holes with the ring flange flush with the adapter surface. The cone-screw hole in the block is #10-32, the same as that used in the Conetrol scope base, which provides side-to-side windage adjustment, if required, as the bases are also drawn down and held securely in place by the coned set screws.

It’s important to position the set-screw holes in the block so they have some draw-down effect as they are tightened. Here the hole centers are drilled 0.110 inch below the top and bottom of the adapter surface. I used the same size cone screws as were used in the Conetrol mounting. The Conetrol ring-mounting system is very sturdy and provides excellent alignment along with a scope ring that draws down and fits precisely to the scope base.

In my opinion. no mounting systems are more attractive than Conetrol, and they are very rugged for any mounting application. I chose to use the horizontal split-type rings over the projectionless style offered by Conetrol, because in this particular application they are much easier to work with. This is particularly true where several varying size shims would be used on the pistol barrels, as well as the scope tube.

Each of the bored and fitted shims were marked to avoid any mixup, since they were used while the scope was mounted to the different size barrels. Changing the scope from one gun to the other was easy, and sighting-in each gun was well within the range of reticle adjustment for each handgun. In addition, there is major right-to-left adjustment within the adapter should reticle adjustment reach either extreme. This is accomplished by adjusting the lateral cone screws.

Mounting the Scope System As I used this unique scope-mounting system, I couldn’t help but wonder if the same application had ever been tried and used before. Though it appeared different, it proved to be very effective in determining the true accuracy potential of these very 22 semi-automatic barrel. Note laterally opposing cone screws used to anchor the sets of Conetrol rings together. This is what makes the mounting system possible.

Pictured here is a Hi-standard Tournament Model .22 semi-auto with a 4X Redfield Sportster scope. capable .22 rimfire handguns. Groups ranging around 1 inch or less at 25 yards are quite difficult to attain with open sights. Arriving at a true evaluation of handgun accuracy or ammunition potential, even with excellent visual acuity, is often difficult. This was not the case with the scoped handguns. Group sizes with the scoped pistols were reduced substantially, even compared to my best open-sight results.

No special method of hold or rest was required to shoot the scoped handgun. Resting the barrel on sandbags, using either a oneor two-hand hold on the pistol grip, produced a steady position with excellent groupings. I also used the method where the triggerguard and frame of the gun are held against a medium-firm sandbag and the pistol barrel is quite free to move as the gun is fired.

I discovered that uniformity of hold is very important, even if the gun appears to be rock solid over the bags at the moment of trigger break. With the use of a scope, groups of five-shots at 25 yards using a variety of .22 Long Rifle ammunition averaged from under 1 inch to around an inch, depending on the match between ammunition and barrel. There is no getting away from the fact that certain bullets do better in a given barrel.

As I would change from one brand or style of bullet I would fire a normalizing shot to condition the bore to that particular bullet. Not always, but sometimes, a semi-flyer would occur, and I could relate this to this first shot on several occasions. This may be a little known fact among high power rifle shooters as well. The coefficient of friction in a barrel can be changed with 22 semi-automatic handgun.

Conetrol scope rings, along with the special adapters used to join them, make a solid and attractive mounting system. different bullets, thereby affecting bullet impact as they are used. In the case of copper-jacketed bullets, total copper removal from the bore may be necessary using a good bore solvent. This may be a significant factor where extreme accuracy is being sought. As I anticipated, the heavier model pistols would produce somewhat better accuracy, just as in much of the rifle shooting I do.

Here the heavier barrel, Hi-Standard Tournament pistol and the heavier barrel Ruger Mark II did very well, with the Hi-Standard holding a slight edge. But both the Browning Challenger and the lighter barrel, Hi-Standard Dura-Matic shot very respectably. Conclusion I learned a lot by mounting and using a scope on these smaller .22 semi-automatic handguns. It would have been impossible to determine the true accuracy potential of these guns with open sights.

The mounted scope looks attractive atop any of these .22 semi-automatic handguns—even for someone who wants to make this a permanent mounting. The Conetrol rings, in combination with this special adapter, proved to be a very effective means of getting the job done. ■