6/10/2011

Back in the early ’90s, when I was a gunsmith at Behlert Precision in Pipersville, Pa., I performed quite a few reliability upgrades on M1911 pistols. Although the Government Model was (and arguably still is) a top contender for the title of “best combat pistol,” the reliability of the original mil-spec design was less than stellar. Originally designed for a 230-grain FMJ bullet, the M1911 had difficulties feeding the hollow-points popular with police and defensive shooters. Compounding the problem was the abundance of different chamberings and barrel lengths, as well as the proliferation of aftermarket M1911 parts and magazines made to varying tolerances.

Fortunately, the M1911 design is endlessly adaptable and is easily tuned for virtually faultless functioning. The skilled ’smiths in our custom shop, under the tutelage of famed pistolsmith Austin Behlert, developed a comprehensive M1911 reliability checklist. The following is a summarized version of that checklist, covering some of the major causes of—and fixes for—M1911 reliability problems. Generally, any of these problems should be corrected by a qualified M1911 pistolsmith, although some are not beyond the scope of an experienced home gunsmith.

Feeding
Ensuring feeding reliability usually begins with throating the barrel and polishing the feed ramp in the frame. If you lack confidence in your own skills, leave this to a gunsmith lest you ruin these expensive components.

Original factory barrels have a minimal bevel leading into the chamber, sufficient for 230-grain ball loads but often unreliable with other bullet shapes. This bevel or throat should be extended all the way around the chamber mouth. This can be done with a Dremel tool, performing the initial shaping with a grinding bit, smoothing the contour with a grit-impregnated rubber Cratex bit and hand-polishing to a mirror finish with fine (600- to 1,200-grit) abrasive paper.

The throat must be ground flat at the same 35 degree angle all the way around. To keep from cutting it too deeply into the chamber, it should not be funneled. Trim an empty case until its rim is even with the original bevel, insert the case into the chamber and scribe a faint line around the case rim at the chamber mouth. This creates a reference mark not to be crossed when grinding the throat.

To complete the job, the corner of the barrel throat leading into the chamber must be very slightly chamfered. Without this chamfer, the cartridge may partially enter the chamber but fail to go fully into battery. Don’t overdo it: Too much of a chamfer reduces case head support. Polishing the feed ramp in the frame is equally important. It is not necessary to remove all the machine marks in the ramp; all that’s needed is to smooth the overall surface. Run a 1/2-inch wooden dowel wrapped with a piece of abrasive paper along the ramp, maintaining the original 31-degree ramp angle, and avoid creating a funnel. I usually start with 600- or 800-grit paper and use successively finer grits until the desired polish is attained.

Feed ramps differ depending on chambering and frame manufacturer. A mismatch of caliber and feed ramp can produce a nosedive jam, in which the bullet nose hangs up on the feed ramp instead of sliding into the chamber.

When the barrel is placed in the frame and pushed all the way rearward, there should be a gap of about 0.030 of an inch between the feed ramp and the barrel. The absence of such a gap can produce feeding problems and must be remedied by a professional pistolsmith.

Feeding is also facilitated by polishing the chamber, accomplished by chucking a 3/16-1/4-inch wood dowel in an electric drill, wrapping the free end of the dowel in a strip of very fine (1,200- to 2,000-grit) abrasive paper, and running it in the chamber at low to moderate speed for a few seconds. The abrasive paper roll should be snug in the chamber, and it should be inserted only until the shoulder at the chamber mouth is felt.

The breechface on the slide should also be polished, and the upper edge of the firing pin hole slightly relieved with a needle file, to keep case rims from hanging up on it as they slide up the breechface.

Proper extractor tension and shape is also critical, to allow the cartridge case rim to easily slide under the extractor claw as the case travels up the breechface during feeding. The entrance to the claw should be beveled and slightly flared, and the extractor carefully bent so that about 5 pounds of pressure is needed to push a case rim under the claw. Excessive tension can cause the rim to hang up as it slides up the breechface.

Other contributors to feeding problems include a weak recoil spring, improper breechface dimensions, insufficient taper crimp on the ammunition, and magazines that rub on the underside of the slide. A weak magazine spring or old-style follower may allow the top round to nosedive into the feed ramp. Original G.I. magazines should be replaced with modern designs having parallel feed lips, strong springs and improved followers.

Extraction And Ejection
Insufficient extractor tension can prevent reliable extraction from the chamber. Ejection port dimensions are also critical. The bottom edge of the port—located about 0.615 inch above the slide rails in the original specifications—should be lowered to around 0.500 inch (some gunsmiths go lower, particularly when a red-dot sight is installed) with a milling machine, or by using files or a Dremel tool. If the job is done by hand, it’s useful to scribe a faint reference line on the slide at the desired port height. Again, be careful or defer to a gunsmith.

The inside bottom edge of the ejection port should be beveled using a small file, and the rear face of the port should be fluted with a 3/8-inch stone in a Dremel tool to help the case spin out of the gun. The flute should be deep enough to nearly contact the extractor tunnel in the slide. A flute that is too shallow leaves a wall at the rear of the port that can cause a momentary stutter in ejection, potentially contributing to a smokestack jam, in which the empty case projects from the ejection port.

On full-length M1911s in .45 ACP, replace the stock short ejector with a longer Commander-type ejector to initiate the ejection process earlier. Ensure that any such replacement ejector has adequate clearance with the slide and is not so long that it prevents ejection of live ball ammunition.

Ejection problems may also be caused by a too-strong recoil spring, easily diagnosed when cases barely dribble out of the ejection port instead of landing together about 7 to 9 feet to the right rear of the gun. Determining proper recoil spring tension is a bit of an art: The spring should be strong enough to ensure positive feeding, but should also allow strong ejection. The choice of the proper spring varies with slide length, caliber and load power; the recommendations from Wolff Springs are excellent starting points. Recoil spring reliability may be aided by the installation of a full-length guide rod, which can prevent the spring from kinking. The head of such a guide rod may have to be relieved at the top to prevent contact with the barrel’s lower lugs.

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Firing
Firing malfunctions usually fall into one of two categories: doubling or failure to release the hammer. Doubling, machine gunning or hammer follow (the hammer dropping to the half-cock notch when a round is chambered) can be caused by a defective disconnector, or a hammer and sear that are worn or improperly modified to obtain a lighter trigger pull. Insufficient sear spring tension also may cause doubling, particularly on modified guns with light triggers. Bending the sear spring forward to increase its tension may eliminate this.