Cheddites ARE the SAME size as Win, Rem, cci, Nobels, and Fed primers. I used Cheddites for years, maybe 30 to 40,000. Went back to Win because I had two hammer guns that would pierce the primers. I made the change and end of problem. If memory serves me correctly the Fiocchi and maybe the Rio primers are bigger in diameter. I've read where the Fio's are now being made to the standard size 209 diameter.

I’ve noticed the last couple years my three hammer guns I shoot often do pierce primers but it made no difference what brand of reload primers or factory shells pierced most all .