I had a partial case head separation using a 1.8oz buffer

[BluntForceTrauma]

Note, for this comment, post #61, it's a pic of the Odin barrel chamber chamfer, a 2-step angle radiusing... [FONT=&amp]It looks like Odin does a double angle chamfer and the step appears to line up with the steeper/deeper chamfer.[/FONT]

GF, what you're calling a "double-angle chamfer" is really just the standard M16/5.56 way of doing it. First they do a 120° cone to help bank an errant bullet tip into the chamber, and then they radius the edges of that cone .0625 where it meets the chamber mouth to round off the edge.

Googled "Sectioned 5.56 Case" and found the attached. Looks like the "web" thickness mates up just fine with the M16 standard feed cone dimensions.

Note also how the difference in web thickness allows the FC case to hold more powder than, for example, the PMC case.