This is my initial testing with the 181 Hammers with the 300 WSM. My rifle is a custom built Surgeon by them with my reamer for the Berger 215's. I tested the Hammers at a COAL of 3.085" giving me a CBTO of 2.350" with my comparator. Bartlein 10 tw in 5R, Norma brass, CCI BR-2 primer and IMR 7828 ssc. My beginning charge was 65.0 grains and final charge was 69.0 grains (this load was compressed for me) increasing at 0.5 grains incrementally. My intent was looking for pressure but didn't find any suggesting I may go with a little faster powder. My velocity node was 3034 fps with ES in single digits and velocity range through the initial testing was 2923 fps to 3098 fps at max. As I said, I was only looking for pressure so all rounds were fired at 100 yards at the same POI. My group measured 0.8" with 2 outliers in the group, one of which was a fowler. I would like to add that because this rifle was set up specifically for the Bergers the jump for the 181 Hammers was 0.143" to the lands and they did NOT mind at all. I also tried them in my older 300 wm built by Charley Robertson and it likes the Hammers too. Hope this helps.