Thread: Poly-tech M-14
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Old November 28, 2012, 21:40   #12
nearnuf
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Join Date: Apr 2006
Location: TN
Posts: 54
I dont have any pictures handy but as already noted in the prior post the Chinese bolts are not marked. The USGI bolts are typically marked with part number, manufacturer code, heat treatment lot number and, steel supplier code although the markings varied with manufacturer. They also have a punch mark in the middle of the top of the bolt indicating that the bolt has passed high pressure testing.

Additionally, the Chinese bolts were manufactured using different steel alloys from USGI (8620-USGI vs. 4135-Chinese). The bolt locking lugs are also dimensionally slightly narrower than USGI specs. This results in USGI bolts typically not being drop in parts in the Chinese barreled actions. Headspace needs to be checked and adjusted as appropriate.

SAI commercial bolts can be confused for USGI Springfield Armory bolts but have different part numbers stamped on them and will not have the high pressure test punch mark.

Nearnuf
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