From left to right:
The first magazine is the early "exposed base" which was used to approximately serial number 4500. There is an earlier version of this magazine which is not two tone. The Colt pistols and magazines were heat blued, and Colt had been tempering the top of the magazine before blueing them in charcoal ovens. Colt found that the heat of the blueing process was removing some of the temper, and started tempering the magazines after they had been blued. The upper part of the magazine was dipped in molten cyanide and quenched in oil to give it the proper temper. The blue was removed to the depth the magazine was dipped in the molten cyanide.

The second magazine is the "keyhole" version. There had been a problem with the backs of the magazines cracking from the tempering process. To give the magazine a little more spring a "punch and saw cut" was approved to help prevent the cracking. This magazine was used from approximately serial number 4500 to 40000.

The third magazine is the standard lanyard loop magazine. The lanyard loop magazine was discontinued in 1915 at serial number 125566, as noted in Colt's records.

The fourth is the standard magazine with no lanyard loop. This magazine was used until the 1940 time period.

The fifth magazine is the standard magazine with the new tempering process where the magazine was no longer dipped in the molten cyanide for tempering. Another version of this magazine does away with the pinned base in favor of a spot welded base.

The second picture shows the "punch and saw cut" of the earlier magazine.


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