I agfree with Colorado4QWheel. I have already been loading on my 550 given that 1994 and that includes several thousand CCI primers. I haven't had an issue with them not heading in straightforward. I have talked Together with the Dillon men and women many times, but never about primer issues, https://federalprimers21093827.dbblog.net/5194153/about-federal-primers-gm210m