I use a mixed bag of shotshell hulls and have noticed variations in primer pocket size. Federal hulls seem to take any primer I've tried, Federal, CCI, or Winchester. I've hed Winchester hulls that have too large a primer hole, barely any tension when the primer is inserted, can seat some with just my fingers.
Then the big mystery, some Peters hulls, nice paper ones I'd like to use, that have an extremely small primer hole, can't get a primer started into them. I've never seen Remington primers for sale, though they must have them. Would R-P primers work in these, why aren't all 209's the same?