So it looks like the bottom line is a squib - most likely because of a round with too light of a charge - left a bullet in the bore. Thankfully the bullet didn't travel far enough for you to chamber a round with the bolt going to full battery. There is an angel somewhere looking out for you. It's a tough call on the barrel. The pressure had to go somewhere - if you were lucky the bullet never went fully into the bore and the gasses blew past the bullet before it fully engaged the rifling. Worst case it damaged the barrel. Did you save the squib bullet and case? You should be able to tell by looking at the bullet if any gasses went past it. If you saved the case is the primer bulged or the case bulged / cracked anywhere? If the primer looks OK and the bullet shows signs of gas burns then your barrel might be OK. I don't know if there is a machine shop or gunsmith around that can check the bore or MPI the barrel.