Norma is the best I've used in the 300 WM. If anything, the Norma (light) brass that weighs~217 grains will allow a higher powder charge due to it having a higher case capacity, usually about 1-1.5 grains more than brass weighing 235-240 grains to achieve comparable velocity. If you don't overpressure Norma brass, it should last twice as long as other brands, namely RP. However, even with stiff loads of H1000 and a Berger 215, I have not experienced abnormal softness in the head as others claim.