My Good MikeM
Before one gets drastic with reamers and grinders and removing metal that cannot be replaced,
I like to recommend making labeled castings of each chamber and measuring them with a micrometer ( not caliper ) , and measuring all the chamber throats with pin gauges.
It never hurts to take measurements!
And, if ? only some? rounds do not seat, and one can see or feel or measure slight bulges, the issue may be a step in the loading process itself ( which it appears you have already discerned... )

I have similar problems with ?some? of my .45 Colt loads, and after weeks of measurements and copious notes and etc, I finally did like Abilene and keep my tightest cylinder handy as a ?try gauge?.
Then I took the ?drastic step ? of gently sizing (again) the loaded rounds that did not fit and ?bobs yer uncle? they all fit and shoot accurately!
Sometimes, a lead bullet just won?t seat correctly or crimp quite right, but a gentle application of the sizing die does the trick for me for straight wall cases .
As always, your mileage may vary,
Always wear your reloading seatbelt,
read and follow safety instructions, do not mix open flame and gasoline,
Use your safety equipment, goggles, breathing mask and safety armor,
And if you see me running, follow immediately....
Yhs
Prof marvel