I think it was bad primers. I switched to Wolf small rifle, and the reloads worked fine in both the Inland and Standard Products I sold, and the Winchester I have. I haven't had a problem since. I even had a problem in my retro AR build with the same lot of primers. Some were just WAAAAAYYYY too hard! I am really fond of the Wolf primers, as I have had excellent luck with them.
BTW, I will be sure to post some pictures of me blasting with the Winny, wearing my Beo Gam "duck hunter" early Viet Nam cammies.... Appropriate for both the Carbine and the retro 602 clone AR. I love the Beo Gams. By the time I was in the Army in the early to mid 70s, all I saw was OD, some ERDL and occasionally some tiger stripes on the SF types. In the late 70s when I was in the Air Force Reserve SP unit, we were switching to woodland cammo.