My guess is that you got a bum lot of brass. It happens. I uniform all new brass primer pockets and debur their flash holes. Its something you only have to do once. Years ago, I bought one of these
Primer Pocket Uniformers sets. The workmanship on these are
Top Shelf and I consider them one of the better values (like Ross brakes) that I ever bought. Mine have not lost their sharpness in countless procket normalizings and if they ever do, the seller will resharpen them for free! The price has slowly gone up since I got my set for $25 but so has everything else. If I used a lot of mil-surp brass which have their primers crimped in, I would definitely get one of these
Primer Pocket gauges. For the few Lake City cases that I pick up at te range, my RCBS
Primer Pocket Swage Tool has proven to be a reliable tool as well, not requiring a subsequent check after processing. You should not have to verify your 450b primer pockets with a gauge. There is something wrong with them if they won't seat Rem 7 1/2 primers and fight seating all primers in general.
Hoot