This is generally caused by primers being seated proud by a smidgen. Measure case length with calipers before and after seating a primer and you'll find out how proud they are.
1. Primer seater equipment or method sucks. Squeeze harder.
2. Primer pocket in brass not deep enough. They sell primer pocket uniformers that cut the pocket to the right depth. I have never had this problem with good brass.
3. Primers are out of spec. Throw them in a fire and move on with life.
4. Primer pockets might be dirty. Running a uniformer in will clean them up.
I tried a case with and without a primer in the chamber and it was still tight when I close the bolt.Measure your primer pocket. Measure your primer to the tops of the anvils to the base. Measure your primer from the top of the cup to the base. Measure how far below flush your primer is seated.
The answer is in your hands, you just need to measure it.
Not every die will size the body down by the web. Often, what they call a Small Base Die will have tighter dimensions and affect the lower part of the case body, but regular dies may not.
I’m assuming you only bump the size about a few thousandths using a body die or a FL Size die or similar?
If your sized case will allow an easy bolt closure, that bulge is just cosmetic. Test to see if a sized case will cycle easily before you address the bulge.
Those marks on the primer are usually caused by one or a combination of debris around the firing pin hole or the primer isn’t completely seated, or both. In theory, that primer sits more than 0.002” below the case head so it can’t get touched unless it is in the wrong place or the bolt face has issues.
Then we have a problem cause that will only get worse with cycles. The advice given in that video about having the guy that cuts the chamber or reamer make the dies is often good advice.The bulge cases create resistance when closing the bolt. With a new factory case the bolt will close much easier.
Have a masterpiece arms 6.5 creedmoor rifle. It has their barrel and a Curtis Axiom action.Then we have a problem cause that will only get worse with cycles. The advice given in that video about having the guy that cuts the chamber or reamer make the dies is often good advice.
Who cut your chamber? Can he make you a set of dies?
Why don't you clean the bolt face, some solvent and a toothbrush will do. Your ejector plunger may sit proud, that'll scrape the shit out of brass, and in your case, being some don't, all brass not the same dimension. You may have some brass buildup on the underside of the plunger if you know how to pull it and clean that too.
Yup I ordered a headspace bushing kit earlier today. I already have the bullet comparator.
This is the hot ticket. Took your advice and found one of the top shooters near me willing to share knowledge. Solved my problem. I was not bumping the shoulder back enough. Learned how to set my sizing die for my specific chamber today. Plus some other tips and tricks.Glad that worked out.
If you can find a mentor, you will learn all this much faster. Clearly you can read and watch videos, but a mentor with experience watching you process is way more valuable up front.