I'm shamelessly copying this link from another gun site because it is so informative for us non-metalurgists.
http://www.thegunzone.com/m1akb.html

Read the article and look at the pictures of this detonated M1A and click on the link in it to the article on the failure investigation. It is very well written and explains the failure in a way that any layman can understand.

Interesting, thanks for the link!

Makes you wonder where the barrel came from.
I bought a match grade barrel, a gunsmith chambered it, and it turned up with nothing but .223 stamped on it.
For all I know it could have been substituted for my el cheapo brand. :-)
I rang the maker and they said they leave the markings to the gunsmith.
Another match grade maker apparently stamps something on the ends, but it is cut off during
chambering etc.

I believe that now in Aust. the Smith is responsible to mark the maker and his own name etc. and maybe a serial No also.
JL

I saw that rifle before.
I would still be shaking

JOhnch