what is stamped on my bolt?
I have a 16'' kit from J&T, and the bolt has lettering on it. it looks like 'MPA', but i am not sure if the last letter is an A. What is the lettering, and who makes your bolts?
I was also wondering who makes your 'military contract upper' and 'Colt contract fire control parts'?
so far your 16'' CAR kit has been excellent, Thanks.
Probably "MPI" for magnetic particle inspected.
Just another marketing tool, some say. For sure nothing wrong with it.
If it is MPI then it means that your bolt has no fractures that will cause it to fail later. It may help marketing but only to people who like things that are tested beyond bubba looking at it and saying that it looks good.
Why do race engines get magnafluxed rods and cranks? cause they don't like to fail and lose.
I personally don't like to have parts fail explosively next to my face. It may be ugly but i still like it.
Odds are that A at the end is probably an overstamp for a different letter and is an overrun from one of our suppliers military contracts for a larger company.