You should be using a std small rifle primer such as the CCI 400 , Fed 205, a Rem 6 1/2, or . The small pistol primers have a thinner .017 cup, as where the ones I mentioned have a 0.20 cup or 0.225 for the fed. Check this out.
https://www.sksboards.com/smf/index.php?topic=56422.0
