I've read a lot about the history of the M16 and the barrel chrome lining.  But I've wondered, when did they first start manufacturing M16 barrels with mil-b-11595e 4150 cmv steel?  Was that something that came along with the a2 or m4?  What were the old m16a1 and Colt sp1 barrels made from?  I'm just wondering.  Anybody here know?

My understanding was that they developed the CMV alloy before AR-10 #1002 exploded during testing. This rifle had an aluminum barrel with a steel sleeve around it. The two materials heated at different rates and thus warped and caused the catastrophic failure. My understanding was that there was some controversy as to whether or not to ship with that aluminum barrel or not, but don’t quote me on that. Regardless, immediately after that, they used the CMV alloy.

I’ll see if I can locate where I got this info.

Attached File

Here it is. Courtesy of the Vickers Guide to the AR-15, Volume I.

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It's too bad the barrel failed in the ar10.  It might have been the issue rifle instead of the m14.  I wonder what they were thinking with that multi-layer design

It would’ve been lighter weight (not accounting for the flutes) and that’s what they were going for