A remark was made about Mil. Spec. primers being "Mag" primers. Makes sense to me but,any info to back that up? Been using CCI #34 in my M1A and thought about using the same for my 5.56. Any links to point me to? Thanks. Mike.

My Speer Manual (the #12, not the latest one) says that the CCI #34 and the CCI #250 are, in their words, "ballistic equivalents."

This is Speer's word on the question. How well it translates to other primer manufacturers is a question I can't answer.

Nor Cal Mikie: I got that data point from a CCI Technical Representative. Per telephone discussions with Guy Neal, CCI Primers 800-627-3640 ext 2223, the CCI #34 primer is a less sensitive (i.e. "harder") primer than the CCI commercial primers. Mr. Neal also stated that the Mil Spec primers are magnum primers. Evidentially the military believed a magnum primer would provide more reliable cold weather ignition than a standard primer.
Winchester primers are also magnum primers.
I have not found a specification that provides energy levels of primers. Not even in Mil-P-46610E “Primers, Percussion for Small Arms Ammunition†This specification used to be available to the public for downloading at http://dodssp.daps.mil/assist.htm. Since 911, all dissemination of knowledge from Government sites has been forbidden by the Security services (they really don’t know what is important and what is not, so they made it all off limits to the public) and now you can't get a copy.