does anybody know what a R stamped on the trigger guard of an IBM M-1 Carbine signify

does anybody know what a does anybody know what a R stamped on the trigger guard of an IBM M-1 Carbine signify? Tried looking it up in the books today at the show and couldn't find anything... I know a bunch of them were reworked at Red River back in the day, and I was wondering if anyone knows what RRAD used as an arsenal mark??? of an IBM M-1 Carbine signify? Tried looking it up in the books today at the show and couldn't find anything... I know a bunch of them were reworked at Red River back in the day, and I was wondering if anyone knows what RRAD used as an arsenal mark???

Are you sure it is an IBM trigger housing?

BTW I moved this thread from the M1 Garand forum :thup:

Carbine rebuild marks were placed on the LH side of the stock above the trigger or in front of the sling ramp cut as far as I know. Is the mark visible with the carbine assembled? Maybe it means 'REPRO' :) Just kidding!