howdy
I loaded a batch of 130gn lead bullets into some once fired,resized lapua brass and fired them no problems.The next batch I tried to load,all
belled the necks so much they wouldn't chamber.I cant figure out why this happened the second time,not the first.The only thing I can think to do is seat the bullet somehow to the correct oal and then run them through the seating die to crimp the cartridge closed.Another thing is,when a fmj bullet is placed into the neck,it slides in and out! Has this happened to anyone else?

Sounds like the necks are work hardening or that your sizing die is not reducing the brass at the neck enough (lapua brass a lil thinner?). Check your sizing die, if it is ok you will have to anneal the brass.

Just a thought, most dies stretch the brass a whole lot and until I changed to a RCBS X-die, I needed to trim nearly every time. This was especially severe with my Lee die of the old expander design. Could your brass have grown too long?