03-05-2018, 11:59 PM
LRRPF52 Wrote:Looks like it was through-hardened so brittle, that it shattered like glass.
There needs to be a balance of surface hardness and substrate ductility on bolts, with a viable alloy.
If you heat treat any of the appropriate alloys to the extent that the part is brittle like that, it doesn't matter what alloy it was made from, how well you MPI it, or coat it with chrome.
It will shatter like glass.
A big thing to notice is whether the extractor is intact and in position or not when you see a kaboom. When a case fails as the cause of a catastrophic failure, the pressure relief is now managed by the path of least resistance after the high pressure gasket (your brass) has failed. The gas path normally blows the extractor out, blows the magazine out onto the ground, eggs out the lower receiver magazine well in many cases, eggs out the upper, and often cracks the bolt carrier.
None of that happened with this, and the extractor is sitting in the extractor pocket, still held in place by the pin, but all the bolt lugs have shattered off like crumbs. Brass looks really clean as well.
Yeah this was not a normal kaboom. There was no gas from the failure introduced into the receiver. All the gas went forward which is lucky in hindsight