Mec-Gar measurements

[Dwight Gruber]

Note 10/24:

I have revised this chart to include an fxo magazine, graciously provided me by John Sabato for the purpose. I have also recalculated the average internal OAL to include only the original magazines; this permits an actual comparison of the aftermarket mags to the originals.

--DG

A little while back Unspellable wondered about the internal overall length (OAL) of Mec Gar magazines compared to original Luger magazines (in a post I can't find rght now or I'd respond there). The thesis is, that since the modern 9mm Parabellum cartridge is shorter than the original design, a shorter internal magazine OAL is necessary in order for the bullets to ride on the front of the magazine and sit at the correct angle for proper feeding into the chamber. Mec-Gar magazines are by reputation particularly good-feeding magazines for Lugers. The question, then, is: do they have a shorter internal OAL to compensate for modern cartridge length?

Having just purchased a shiny new digital caliper, I decided to break it in by making some measurements. As the inside jaws are not quite long enough to make the direct interior measurement, I measured the exterior and the thickness of the metal of the magazine body, and then subtracted the front and rear thickness to get the internal measurement. I thought it would be useful to see a wide selection of magazines, so I measured a representitive selection of what I have at hand. Measurements are in inches.

magazine.................ext. OAL..............guage...............int.OAL
DWM Comm................1,092.................,018..................1,056
DWM Comm................1,090.................,018..................1,054

Erfurt Armorer Spare....1,097.................,018................1,061
(2 stamps)
Erfurt #8895t...............1,098.................,016................1,066
(1 stamp)

DWM 1st Iss. #1026...1,105.................,018.................1,069
DWM #5881d..............1,097.................,018.................1,061

DWM Police..................1,097................,017..................1,063
(u Commercial)

Mauser #4289w..........1,067.................,013.................1,041
(blued tube sE/63)

FXO #39xx u................1,100..................,015...............1,070

Avg..................................................................... ..........1,060
.........................................................(without Mauser) 1,063

MecGar.........................1,094.................,016............... .1,062

KKK metal.....................1,090.................,013................1,06 4
KKK plastic....................1,096.................,013................1,0 70

Mexican........................1,094.................,016............... .1,062

It is noteworthy that there seems to be quite a range of interior OAL in Luger magazines. It strikes me as unusual that the Mauser magazine is substantially shorter than the Commercial and Imperial magazines. As it is the only one I have, I cannot check to see if it is anomalous, or standard for that model. I can tell you that it does not feed for beans.

For the subject at hand, Mec-Gar magazines' interior OAL fall right at the average interior OAL of the original magazines. I leave it to others to draw conclusions from this exercise.

--Dwight