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Re: Non-Custer Carbines SN check

Posted by Pete Nelson on Thursday, 11 November 2010, at 6:56 p.m., in response to Re: Non-Custer Carbines SN check, posted by JasonZ in MO on Wednesday, 10 November 2010, at 10:34 p.m.

Hi Jason,

Sorry - - I got so carried away talking about hand-loading and the barrel-lining that I completed skipped over your questions about the broken spring-loaded firing pin. It was the very problem you described which prompted the Springfield Armory (in June of 1878, I believe) to eliminate both the spring-guide shoulder AND the spring itself from the Model 1873 and subsequent arms. I even have a small display collection of various modes of firing pin/spring failures (in addition to a display of the different chronological firing pin designs used during the "TRAPDOOR Era"). I have specimens of pins which failed at 1 and 2 locations (and even one which came out in 4 pieces)along the length. And even the re-designed springless pins still occasionally fractured, often in exactly the same locations, the most common of which were:

a) At the fillet directly beneath the head.

b) Along the straight shank between the head and the tip.

and

c) Along the reduced-diameter shank of the tip just below the fillet at the tip.

The major problem with the use of the firing pin return spring seems to be the tendency for the tip section to fracture and then to cause the spring to "wad-up" (as you put it) and cause the broken tip to jam in the forward position protruding out from the face of the breech block, often causing a "slam-fire'". I have one breech block which I had bought for display purposes simply because it has the tip jammed forward in just that manner. So I left it that way and bought another stripped block to use for display. By December of, I believe, 1886 the Armory had switched over from carbon steel for firing pin manufacture to the relatively-new Aluminum-Bronze Alloy which was not only stronger but would neither corrode nor rust.

As far as I know the internal firing pin "tunnel" profile was not changed when the spring-guide shoulder on the pin and the spring itself were eliminated. For purposes of authenticity all of my rifles and carbines have the correct design pin (and a spring, if called for). But I use ONLY the Aluminum-Bronze Alloy pins in my two shooters (the 1884 Carbine and the very-late M1888 RFound Rod-Bayonet Service Rifle) and have built up a good inventory of replacements. The firing pin is one component that I am guilty of probably over-lubricating (usually with G96 Gun Multi-Lube), especially on the two "shooters". And if the pin on either of those two guns shows any bending or abrasion at the tip or appears to being hanging up going into the "tunnel" of the block, I replace it immediately.

One of the chronological changes made in the pin design occurred in (I believe) April (5th) of 1879 was to include a tempering process to improve the ductility of the steel pins. This was nearly a year after the elimination of the spring-guide shoulder and return spring.

Your M1873 rifle (S/N 46974) would have been produced sometime around mid-1875 I believe, so it would definitely have been issued with the shoulder-type spring-loaded firing pin (which wasn't eliminated until June of 1878). So, if you intend the gun to be a "wall-hanger" I would get a shouldered pin with spring, but for firing purposes I would get a few Aluminum-Bronze Pins from Al Frasca, "Red" Daugherty, or Ed Knisely (in York, Pennsylvania).

Best regards,

PETE


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