What length are you guys trimming your brass to my book says 2.840 but I have some once shot nosler brass that measures 2.830 just wondering if I should keep them at Since I have winchester brass that's 2.840
Most factory brass is going to be a breath short.
As it fire forms... it may get a breath shorter due to brass flowing to the specs of the chamber... however, the growth is almost always done thanks to the sizing process..
be it small base dies , FL dies.... or neck sizing only.
Long story short... it's a few thousandths diff... but if you want to maintain the best consistency with loads trim your brass to X length AFTER they are fire formed.