I recommend not removing the primer ... your firing pin will suffer if you dryfire without the spent primer...mark the round to identify it as a dud. Drill it, knurl it... or just use nickle. I use nickle cases for training testing ect. because I don't like loading it...It is harder than brass and it does not grip the chamber as well with hot loads. It can give you false pressure readings...it can easily scratch your dies if it is not clean. it does not like to be resized more than once...<split necks>......just my opinion.........carry onI've heard of people using nothing in place of the primer as well as caulk or rubber. I'd say just but some snap caps or something seems easier.