Primer selections
Lightingman, you can use the small rifle primers of any manuf. Each may give a bit different vel and ES or print on paper in assorted POI. If you dont have a chronograph, then your grouping is about all the info you'll get as far as performance. Reading the case, primer condition and case shoulder movement, is a good indicator of pressure conditions. This is where the rifle and pistol primers will give some widely disparate readings. The pistol primers are shorter, hence will seat deeper in the rifle case pocket, and will give an inaccurate reading of pressure, a couple thousandths set back on firing WILL alter the reading. I wouldnt say they are unsafe, but this is a rifle case at rifle pressures and a SR is different construction from the SP. Its not been a problem in pistol usage as far as misfires.
Its been my observation that the tougher the primer in the rifle, the longer my cases last. I've even used the REM 7 1/2 with no problems in the PS90, and thats a tough sob as far as primers go. Seeing as how the weakest part of the 5.7 case is the primer pocket, it makes sense to me to try to reinforce the strength of that area any way I can, and the thicker primer construction and proper fit is the only way I can see to do it.
The Mag primers are not really needed, the std rifle are hot enough, and are probably hotter in this application than the mag pistol. I got the best vel MAD with the win srp in my chosen loadings, but that may not be the case with your load. My primary load development is for rifle, and what litttle pistol has been more conservative.
