Crazy neck tension, unable to pull bullets.

[Dubious]

Had one of my reloading friends call and ask to borrow my rcbs bullet puller. He loaded some test rounds and on the first firing the case split so he decided to pull them. He was using Barnes TTSX bullets with lapua brass and couldn’t get them out with his handheld hammer puller. I went over with my rcbs puller and it was all you could do to pull these bullets to the point that the table sounded like it was going to split and the bullet would slip out of the puller. I check his dies and we measured his bullets and they were both correct.

Anyone have any ideas on what is going on with his neck tension. His theory is that barns bullets are to hard to have the puller be able to bite in but I showed him how easily it pulls other factory loads and it was biting into the bullets on his rounds so hard it was damaging them.