Increases case pressure signs
I am shooting a 7.62 cal QD YHM can, on an 18 inch chrome lined Sabre Defense barrel in 6.5 Grendel with mid-length switchblock. So far, I have only shot factory 120 grain Wolf MPT through it. I have been having signs of increased pressure in about 1/2 of my cases (extractor / ejector markings on cases, difficulty with extraction). Fouling also sneaks up the case walls in an irregular pattern after 10 rounds or so. I want to get into reloading, so I cleaned all the cases. In the ones without the visible signs on the cases, the primers seem to go in with the correct pressure. With the ones that have visible pressure signs the primer pockets are so loose that if new primers are loaded into cleaned cases, the primers back / fall out on their own. I threw out the entire batch, as there may be invisible problems. The cases also took a lot of force to re-size. Is this normal for running a suppressor? I've shot a lot of 7.62x39 through this can on both AR/AK with no issues, although since they were steel cases I never bothered to examine them in detail.
Function wise, I shot over 130 rounds of the factory ammo over a day, it functioned fine, although the cases were really dirty. With gas off, extraction was difficult. Unsuppressed, with gas full on, the rifle seemed to clean itself out (much cleaner cases).
I pulled some of the Wolf ammo, its ball powder, charge weight is 29.2 grains. case dimensions and OAL were correct. Normally, I don't bother with reloading, but 6.5 ammo is pretty expensive. Could I have a head-space issue? I've been thinking of pulling some of the factory Wolf rounds, and reloading them with a known powder from the Hornady manual (a 2520, IMR 4895). Is this a good/bad idea?