Grabbed four of my light frangible loads (23.5gr IMR4895, 50gr surplus frangible bullets) (should have grabbed more rounds). Before, they needed gas 3. Tried gas 3, 4, 5, 6...all failed to lock back the bolt.
Later this week it'll get into the 70's. Will need to shoot again and see if increase in outdoor temp (will get ammo up to the ambient temp too) makes a difference. Will try gas 7 with the frangibles. Oh, every mag tried properly lifted the bolt hold open when empty and the BCG was manually pulled fully to the rear, so it wasn't a mag problem. All rounds fired were stored in my reloading shed and it got in the freezing temp range last night. Glad the XCR has an adjustable gas system, and maybe it's working "as it should be" now.