It's A Gas

American Handgunner, May, 2000 by Charles E. Petty

Network Custom Guns transforms the 1911 into gas operation.

John Browning patented the basic idea of a tilting barrel in automatic pistols in 1895. That feature is one of the great strengths of the 1911 pistol; it is also one of the Government Model's greatest weaknesses.

The tilting barrel makes it possible for a fairly small handgun to manage the force of a cartridge with relatively high pressure and heavy recoil. It works by locking the barrel and slide together and allowing them to recoil as a unit until the bullet leaves the barrel and pressures drop to manageable levels.

Browning's seminal 1911 pistol is probably the most important handgun of the century. As issued, with the generous tolerances Browning deliberately gave it, the 1911 is a highly reliable service pistol. With those same tolerances removed by gifted gunsmithing and modern aftermarket parts, it is a tackdriving target pistol. Please note the use of the adjective "gifted." Accurizing the 1911 isn't easy to do.

That's because of the tilting barrel. In order to achieve match-grade accuracy, the barrel has to return to the same point in relation to the slide every time. It takes a lot of work and, sometimes, a little luck to get things to come out right.

Enter now John Adkins, a self-taught gunsmith and fan of the Government Model. He studied the gun and concluded, "If I could make this a fixed barrel, it would really shoot." Thus began an eight year process of trial and error.

To have a fixed barrel would mean that the slide would have to move independently of the barrel. That's blowback-- another of Browning's patented operating systems-- but blowback is not suitable for the .45 ACP because of the raw power of the cartridge. Adkins' answer came in the form of a gas retarded blowback system, which, of course, was another Browning patent.

The Gas Challenge

The challenge Adkins faced was to get a gas system into a package that was never intended for such a system. There is a simple difference between gas operated and gas retarded. A gas operating system bleeds gas out of the barrel-- usually near the muzzle-- and uses it to push an operating rod, or the bolt, to the rear.

By comparison, gas retarding bleeds gas somewhere near the chamber mouth and uses it to push forward and slow down the rearward motion of the slide or bolt.

Actually it's a pretty simple concept: take a little of the gas and use it to keep the slide closed until the pressure has dropped when the bullet is gone. But simple ideas are sometimes the hardest to execute.

When you deal with gas ports, it is not just a matter of drilling a hole and letting the gas go to work. Make the hole too large and the gun will cycle too slowly-- or not at all. Make the hole too small and the gun will beat itself to death.

Most gas systems have a port, a gas tube and a piston. One of the challenges Adkins faced was finding a method to temporarily connect the slide to the gas source. Remember, the gas needs to push the slide forward at the same time recoil forces are pushing it to the rear. Adkins' solution was to affix his gas piston to the standard recoil spring plug. That works nicely.

Barrel Construction

Adkins begins with a Douglas premium barrel blank 1.875" in diameter. It is the largest diameter Douglas makes and Adkins needs every bit of it to fabricate his barrel and gas port out of a single piece of steel. At first glance you'd think that the barrel is simply one of those ramped barrels that are popular with the .38 Super and the other high-pressure cartridges. But then you'll notice that there's no barrel link and there's this funny looking tube sticking out of the bottom of the barrel.

The construction method involves machining the entire bottom area, including the feed ramp, from the large diameter blank. The feed ramp and the area that sits between the slide rails are one piece. The hole for the gas port is drilled through the 0.6" deep bottom lug.

The stainless steel gas tube is then screwed in place and the hole in the bottom lug is filled with a permanent screw. When all is said and done there are only two parts to the barrel and both are stationary.

The gas piston is also stainless steel and fits into the gas tube with only about .001" clearance. The fit can't be too tight or it could bind and accumulate powder fouling, but if it's too loose it won't provide enough retardation. The piston has four flutes and really appears to be almost self-cleaning. After several hundred rounds, the piston is sooty, but still moves freely within the tube.

Since the barrel of a gas gun doesn't tilt, the location of the firing pin is entirely wrong on a standard slide. Adkins installs a bushing to move the firing pin up a bit for proper ignition. He reports that future pistols will be built using specially ordered Caspian slides without drilled firing pin holes. Thus, he can precisely locate the firing pin to work with the gas gun barrel.

There is an unusual combination spacer and recoil buffer made of an alloy of brass, titanium and magnesium. The purpose is to fill the space occupied by the standard recoil spring guide and also provide a bit of a cushion for the slide.