The quality of the receiver has nothing to do with these pictures it's extreme pressure that would destroy any good receiver. Actually the Rock Rivers as well as Stag, Sabre. CMMG and about a half dozen more receivers are held to closer tolerances than Mil-Spec. Mil-Spec is good, but not always the best contrary to popular belief. But any thing that meets the Mil-Spec standards and requirement should never have a problem when it comes to fit and quality. Both issues regarding the pictures as Scubie's picture of "high pressure" caused by a bullet being recessed in the casing and being fired and the one in my pictures caused by a barrel obstruction.
Thank God they were not steel machined receivers!!
Neither officer was severely injured.