ORIGINAL: stubblejumper
The magnum primers will decrease the effective burn time and increase velocity. I gain over 100 fps in my 06 when switching from 210 to 215 primers with 180 grain bullets. This should work in any case capacity limited cartridge.
Of course the extra velocity is a result of extra chamber pressure produced when using the 215s.You can simply use 210 primers,and add a grain or two of powder to achieve the same results.
That what I was thinking. Anywho, I have had horrible luck with 215's and 308. Velocity spreads up to 100fps with Varget and 4064.