Tight is good - Pistol Smithing

American Handgunner, Nov-Dec, 2002 by Alex Hamilton

Factory .22 caliber barrels in pistols such as Smith's Model 41 are supposed to be built for target shooting or to accuracy standards a cut above the norm. But, they are still chambered to handle all brands of ammunition from the cheapest and poorest quality to the finest. That's the way it has to be in today's world of generalities. Manufacturers cut rimfire chambers -- the heart of rimfire accuracy -- with an exceptionally long chamber and a 50 lead (the point at which the bullet enters the rifling) in front of the bullet so all brands of ammunition will fit.

Chamber diameter is also left on the generous side. Match chambers, on the other hand, are cut by a custom pistolsmith to tight tolerances with a lead that will allow the .22 rimfire cartridge to chamber easily in a semi-automatic pistol. If the gunsmith uses a plain old "match reamer" made for a rifle, the .22 cartridge will come within 3/32" from fully seating and the force of the semi-automatic bolt will not have enough energy to push the bullet into the rifling as does a bolt-action rifle. The solution to this problem is to cut a custom chamber with a 10 to 20 lead, such as those cut by a Bentz reamer, which are available from all reamer manufacturers.

The Bentz reamer was developed to cut chambers so the bullet would be held tightly in the chamber with minimal wobble. A 1.50 lead means the bullet gradually enters rifling, and the cartridge has no problem seating when the bolt closes. The only difference between the Bentz reamer and other tight chamber match reamers, such as the Winchester Model 52D, is the lead. With the tight match chamber you may have trouble getting some ammunition to seat, such as heavily waxed Eley Tenex.

For more information, contact Falcon Machining, phone: (602) 482-7333.