Glad you got it figured out. That is a very common problem with the J lock system Remington used. The spring runs the inside of the bolt body during ignition and creates problems.
Jlock are very easy to spot since they have a lock on the bolt shroud unless someone has changed it.
You can remove the seating stem and first drill it out so the plastic tip of your bullets don’t contact.
Next you can use a bullet with some lapping compound on it and spin the seating stem in a drill and lap it for a much better fit.
Glad you got it figured out. I’m going to guess whoever installed the muzzlebrake didn’t dial in off the bore and just off the outside of the barrel which can be far from concentric.