AR Thread

[scaggly]

Out of curiosity (and having a relatively quiet morning ahead), I went and googled it. The best discussion I found was this one HPT and MPI: still viable and necessary or outdated bureaucracy? - Page 15

In a nutshell, some rate the processes citing mil-spec, some don't. A couple of manufacturers chip in, and their rationale is that if the bolt is manufactured using quality steel, quality manufacturing etc., then there is no benefit to MPI or HPT, and that destructive testing (HPT) only reduces the life of the bolt.

Others (but not other manufacturers that I could tell) disagree with this view, but at the end of the day some fairly big names in ARs don't think either process adds much value.

I'm now better educated than I was an hour ago, and it is pretty much settled for me that the two processes aren't needed as long as you're buying parts from a reputable manufacturer.

Of course, if you're machining your own bolt, then some testing might be in order