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With out even knowing what brand of firearm your using and watching what it is doing while your chambering a round it is pretty hard to tell.
Just a thoughtCheck the Over all length of the PPU compared to the federal I have a suspicion that the PPU might be longer
OK here's a QUESS. The Remington has a rotating extractor, after the extractor lip snaps over the rim of the cartridge it rotates a quarter turn before the lugs are locked. It sounds like the PPU cartridge might have a sharper inside edge to the rim and as the extractor is rotating it is scraping off this sharp edge. A contributing factor might be that you have a minimum spec chamber and the PPU ammo is at max spec and is snug in the chamber(not a bad thing, it's something we strive for in reloading by neck sizing) and not allowing the cartridge to rotate with the bolt.