New to forum, hello all pleased to be here. Well I need help figuring out what happened today. I'll fill everyone in on what has transpired.

Bought a 111 Trophy Hunter XP package in 6.5x284 on Sunday. Cleaned it Sunday night with Butches bore shine scrubbed it until patches came out clean. Went out and put 8 rounds through it waiting 5 minutes between shots. I usually break in a new gun better but I was excited to shoot it. So after the 8 rounds I went home and foamed the bore with Birchwood Casey foaming bore cleaner, let it sit 30 minutes then worked it over with the brush and patches, a few patches with butches and then dry patches until they came out clean. Checked the barrel from the chamber as well as the muzzle checking to see any rough or dirty spots, all good. Set in in my cleaning rest with bolt open. It's morning picked gun off rest put in case went to range. Set up, few dry fire exercises loaded first round, squeezed and boom twang. Barrel split from muzzle almost to forearm. Large bulge 3/4 of an inch from muzzle.?

HSM 142gr Berger Match VLD's

Any thoughts, I know there was no obstruction in barrel. Any help would be greatly appreciated.