Do I have big pressure signs?
No published data from Sierra. Only data is from Hodgdon and only data is available for Sierra 155 SMK loaded to 2.775 COAL. Max for that is 48.7c.There's definitely an ejector pin divet on the case on the right and its primer is flatter than the others. Ball powders can generate pressure quite quickly especially when compressed. I would back off. How much higher than published data are you velocity wise?
Yeah, I kinda expected that the velocity would be higher. Just didn’t expect the velocity to jump THAT much from one charge weight to another.So you went over book max and got higher than book velocity. No mystery here.
Moreso than anything else, I wanted to see what it was capable of doing. Definitely backing off that last load. 2700-2800fps is plenty fast out of a 20in barrel imo.Maynard is on point. Local gunsmith in my area shoots FClass with them bad boys and told me if I wasn’t gonna run 30” I better stick to above 168grains and hope for good wind. I shoot out to 1100 in PRS with both a 20” and 22” R700 in 308. I’ve only ever shot Sierra and Varget. The Ginex Primers were no bueno in the detailed PMC Brass we use. We switched to a Winchester primer and the velocity jumped immediately. Most guys are running ELDMs or ATips so availability on those will be sparse in comparison.
What exactly are you trying to achieve that has you pushing Mach speeds?