M14 Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
5,610 Posts
Discussion Starter · #1 ·
I HAVE A BOLT MARKED
7790186-SA
F00069 IN 1 16 LETTERS ALSO ON THE REAR WHERE FIRING PIN GOES IN MARKED D M 5 IS THIS USGI
THANKS FOR YOUR HELP
 

·
Banned
Joined
·
10,629 Posts
I believe you have a USGI Springfield Armory bolt. Generally USGI parts are marked in 1/16" high letters. After market 1/8". I'm sure and hopeful that our resident Master Ordnance Historian would know better than I.
 

·
Registered
Joined
·
329 Posts
jerry/hawk:
dont always assume something is genuine when it might just not be but you never know.
jerry check for a vibrapeened mark "m" on the bottom of the bolt.
the "m" demoted that it passed its magnaglux test procedure.

another way to tell look for a single prick punch mark at the top of the bolt which denotes that the bolt has passed final proof test for repair parts bolts only. this is per the legend on the bolt drawing 7790186.

please also note that the "m" is not always present because i personally have inspected many bolts and its the h&r, hrt, hra bolts and sa bolts which seem to have the "m" moreso than the trw bolts.why i dont know.

also if a bolt is worn or the parking has been redone that vibrapeen mark would be barely visible or not there at all due to glass bead blasting.

the reason for the "m" was due to a heat treat problem that showed up in the first h&r bolts and caused some problems in the early 1960s as per EOSA25810 dated 30 sept 1960 note: on drawing ,
1. each repair part bolt and roller assy shall withstand the firing of one government standard hight pressure test cartridge withoput evidence of failure as determined by magnetic particle inspection for cracks seams and other injurious defects, using a standard 5 turn magnatizing coil with current of 200 to 250 amperes.
apply mpi mark to assy meeting this requirement.
springfield rifle company not the arsenal also produced parts for their guns these would be investment cast not forged.
also remember as per drawing 7267000 the bolt had the prick punch mark after test proof firing and the punch mark was to be colored white so it would stand out to the final inspectors look. jeff
 
1 - 5 of 5 Posts
Top