It was long suspected LMT and KAC were using Aermet 100 for their bolts. Apparently this new Ferrium M54 is being used as a direct replacement for Aermet 100 in the aircraft industry these days which also might explain the electroless nickel finish switching to chrome plating recently.
Anyway the point Im trying to make is that after deep diving into the world of bolt steels to find out why I can't have a $70 uber bolt this is what I found. This Aermet 100/ Ferrium M54 stuff that E-Bolts and E3 bolts are made of are crazy expensive and very limited in their production which is why you can't uber bolts any cheaper.
Last edited by vicious_cb; 05-11-22 at 15:20.
I've never bought a crappy bolt, and I've never had one break. Only ever seen gas rings broken.
Vanadium modified 4330 is the steel all your modern US Navy aircraft* tail-hooks are made from, with the exception of the old F-4 Phantom, that required a Inconel hook as it resided right in the exhaust wash of two J-79s . . .
M54 is actually only used on one type/Model/Series, the T45. And, it is not used in the hook, but the hook shank. The Navy seems to have bought 60 of them.
I don't think you're going to like bolts made from your "uber-steel". In order the get those high material properties they are working in a HRc range of 52 to 54. Carpenter 158 and 9310 bolts are surface hardened to low 60s for wear.
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* F-35 Lightning, C-2 Greyhound, E-2 Hawkeye, EA-6B Prowler, A-6 Intruder, F/A-18C/D Hornet, F/A-18E/F/G Super Hornet/Growler, A-4 Skyhawk, and S-3 Viking.
So whats the current uber bolt steel if its not Aermet 100 or M54?
I've broken 1 bolt in an ar and have seen a few go down. Usually in a short suppressed postie. A friend broke a psa bolt in one but it was thousands of rounds in. Mine was a colt bolt in a 10.5 suppressed gun, I've seen a bcm bolt go down as well.
Last bolt I broke was sadly not in an ar style gun. I broke a hk21 bolt in my K gun(10.5 inch 308). Short full auto 308 though with god knows how many rounds through it. I know the gun was run pretty hard before I got it.
There are three major properties a steel used for a bolt needs:
1) High strength
2) High toughness
3) High surface hardness
Just because a steel has a yield strength of 300,000 psi does not automatically means it will be a good steel for a bolt if it achieves this strength at a hardness of HRc 48-52.
Actually, the best steels for bolts are the same steels used for gears. If you want a new 'superalloy' for bolts you might want to look into Ferrium C61® or C64® steel.
Last edited by lysander; 05-13-22 at 06:35.
I always enjoy reading your posts Lysander. Thank you for contributing.
SLG Defense 07/02 FFL/SOT
No clue. I've personally never broken one in 25 years of shooting.
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