DIAGNOSING FUNCTION PROBLEMS

To diagnose function problems they must be divided into either extraction or reloading problems, and the causes are not always the same.

Extraction problems are further divided into failure to extract from the chamber, or incomplete ejection, usually seen as a form of "stovepiping". Incomplete ejection is usually caused by incomplete slide retraction, or a missing or broken ejector. Underpowered ammo will cause incomplete retraction and "stovepiping".

Failure to extract causes include a defective or missing extractor, burrs or abnormalities in the chamber, or too powerful ammo causing swelling of the case. Incomplete slide retraction is often misdiagnosed as an extraction problem when the fired case is pushed back into the chamber. An oversize chamber will allow brass to expand beyond its elastic limit so that it remains tight after the shot is fired. One caution here, inspect the chamber carefully for cracks that let it expand abnormally.

Complete slide retraction and storage of recoil energy in the recoil spring is necessary for proper reloading. One cause for incomplete retraction is often lack of lubrication wasting the recoil energy through friction losses. In light framed guns, "limpwristing" allows relative slide vs frame speed to slow, thereby diverting and failing to store recoil energy in the recoil spring.

Reloading problems are further divided into magazine problems, or in some cases, extractor or cartridge guide(throating) problems.
Deformed magazine lips or a "sticking" follower are the usual causes. Inadequate springs are seldom the cause.
Although a dragging follower or deformed mag lips can often be overcome with an extra strength spring, this is not the best solution, since intermittent failures will probably continue with the possibility of extractor breakage.

Deformed magazine lips may hold the head of the cartridge down too long in the reloading cycle, so that when it is forced out by a strong magazine spring it rises late and very fast, "jumping" ahead of the extractor instead of smoothly rising up behind it. This forces the extractor to jump over the cartridge rim to reach battery. This may eventually break the extractor, and often mutilates the case rim.

Even when the magazine lips and spring are correct, the extractor can be too tight or the breech face can have a rough surface, so that the cartridge cannot easily slide up behind the extractor as it should. A symptom of this is usually a hesitation or halt going into battery. This is usually misdiagnosed as improper throating.

Stovepipes are usually either of two different problems. Either the breech face/extractor slot is too rough or tight for the cart to move up smoothly behind the extractor and it gets kicked forward without being cuaght by the extractor. It can then either tilt up to a stovepipe or go on into the chamber.

Guns with this problem can seem to run normally most of the time if the extractor jumps over the rim after the cart is seated in the chamber. It is deceptive. One clue may be a mark on the back of the rim made by the extractor jumping over the rim. This is not always present, so lack of a mark is not conclusive.

Or..the mag lips are open too wide and release the bullet end of the cartridge too soon. This is more critical because they can also release too late by being too tight. For instance, the early P11 and P40 mags were modified by cutting back the lips slightly to cure the to late release problem.

The late release problem could either stovepipe or seem to jam on the ramp. Jamming on the ramp is almost a myth. If the cartridge is up in the magazine where it should be, it is already well above the ramp.

Careful study is needed when a usually reliable pistol begins to malfunction. I have attempted to correct some of the misconceptions about semi-auto malfunctions, but there are many and sometimes multiple problems.

Good luck and stay in the X-ring, Jack F

copyright 1966