I got out today to fire off five rounds of 30-40 ammo loaded with 40gr IMR7383, using a Federal GM215M primer under a NOE 316365 weighing 190gr. It was better than it was with a Federal 210, but there was still some unburned stuff. The grains left in the barrel were partial grains rather than the nigh full sized grains I got with the 210s. Bottom line is, there's not enough heat in a LR primer, of any brand, to get this stuff burning the way it's supposed to. Way it's supposed to? Yea, the nitroguanidine, which is the outer coat of each granule, is supposed to explode first. Gases generated by that explosion keep the nitrocellulose from burning with a flame, sorta like putting out an oilwell fire with nitroglycerin. Maybe I'll try a flash tube like the 50 cal spotter round has, or maybe I'll just keep duplexing it. Group wasn't bad, strung horizontally left to right, but all at the same height, which indicates to me that velocity was pretty consistent. POI was about 3" higher than what I'd been getting with 38.8gr of RL19. Incidentally, I found a .5gr difference in weight between 210s and 215M primers.