I don't Imagine It can be what gun they have been shot it, that sometimes shows as being a base bulge soon after sizing. I might almost certainly evaluate you sizing die and powder funnel. The challenge with reloading the 9mm is definitely the tapered case. Since I get fired https://9mm-bullets97406.tkzblog.com/37351859/how-9mm-reloading-brass-can-save-you-time-stress-and-money