Chambering Problems

[Dwight Gruber]

I'm afraid that I don't have the tools to precisely measure the oal of the Winchester, S&B, or Blazer ammunition.

I would like to take a dissenting position to the theory that overall length of the cartridge in the magazine is the primary contributor to Luger malfunction in the 21st century. I am of the opinion that the condition of the magazine feed lips is the crucial factor, and the magazine spring is an associated consideration (as may be bullet shape).

Earlier in this discussion I reported my experiments with magazines and ammunition, settling on the MecGar magazines and ammunition selection which functions best in my variety of shooting-quality Lugers. This was entirely a methodical empirical test.

The original magazines I tried were a random selection which had come with various Lugers I have purchased. Observing these loaded magazines, it was apprarent that the feed lips had variously become weak or bent, that the topmost cartirdge was not held firmly in position, or was not held at the proper angle. And feed angle seems to be the crucial parameter here, if the bullet nose does not approach the breech precisely, it will misfeed.

Having magazines and ammunition which work acceptably might be the end of the matter, except for some experiences I have had since.

I obtained an fxo magazine (until I traded it) which I used to shoot, along with my Mec Gars, and it proved just as reliable. fxo mags are extruded metal, very solid, and have very stiff feed lips.

I recently picked up a proper magazine for my S/42 shooting Luger, blued metal (rolled&folded) tube, aluminum base. Although I did not buy it as a shooting magazine (judging by my previous experience), I have used it several times with no reliability problems.

If the oal of the ammunition was the primary factor, one would expect these magazines to fail as much as the original mags in my first test. In fact, conventional wisdom has it that fxo magazines are excellent shooting magazines.

With one Luger purchase I acquired another aftermarket magazine, not a Mec Gar, in fact I can't find any manufacturer on it. It is fairly leightweight, and only holds seven rounds. I have compared it to a Mec Gar, and it seems to be the same internal length.

I tried using this magazine shooting several times, suffering malfunctions each time. I looked at it closely and noticed that the feed lips were spread a little, allowing the cartridges to rest at too steep an angle. I unloaded it and pressed the feed lips against the shooting bench (did I mention that it is lightweight?) which bent them in a bit. I re-filled the magazine and noticed that the cartridge angle was better, and proceeded to use it without problem. It has functioned without malfunction ever since.

There are some other magazine variables which affect the angle of the cartridge as it enters (or doesn't enter) the chamber. Take all of your magazines and insert one round, then compare the angle which the magazine follower holds this round. This may have an effect on the availability of the last round to chamber reliably, or even be picked up by the breechblock.

The magazine spring obviously has an effect on the angle the top cartridge rides in the feed lips, as it presses the round more or less firmly into place.

As I have been working with magazines while writing this post, someting else has occurred to me. Some magazines work much more smoothly than others, which has an effect on how strongly the spring presses the cartridge into the magazine lips, and also has an effect on how easily the ammunition stack moves up the magazine. This seems to be independent of ammunition, and has
more to do with follower fit and smoothness of the inside of the magazine tube. It may be that this phenomenom is masking itself as a cartridge overall length problem.

--Dwight