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 Large pin vs Small Pin
ScorpionMedic  [Member]
1/18/2010 5:30:50 PM EST
Can someone either link me or explain the differnce. I have a Rock River lower and want to put a timney trigger in. The one i have found says it will fit small pin only.
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SSeric02  [Team Member]
1/18/2010 7:31:35 PM EST
In this context (fire control group parts) it refers to the diameter of the hammer/trigger pins and also the corresponding hammer, trigger and disconnectors. The small pins or mil-spec diameter pins are what is most commonly found and are .155" in diameter. The exception is commerical Colt guns that were made from the late 80s (?) /early 90s up until recently using hammer/trigger pins that were .170" in diameter, ostensibly to prevent the installation of full auto-parts into the weapon and protect Colt from liability. Your Rock River has small pins though.

The pin size may also refer to the size of the pivot pin. Again, small pin being the standard or mil-spec size, in this case of .250". And again, for many years ending in the early 90s, Colt used larger that standard pivot pin arrangements of .312" to prevent the use of full-auto uppers on commercial guns. This obviously doesn't have anything to do with triggers though.
ScorpionMedic  [Member]
1/19/2010 4:26:06 AM EST
Thanks what I needed to know. Thanks for the help!