Hi, I'm a newbie. I'm shooting a 338 RUM all customed assembled with a 30.5 inch barrel. With 90 grns of Retumbo and a 300smk I get 2805 fps. Almost identical with a Nosler 300ab. The Nosler might be more accurate at 600 yds. Now I got a box of 300 bergers and the velocity with the same load from the same jar etc. is 15 fps faster on the same day. To top it off, the berger loads do not have extractor marks where the other two have obvious marks. I"m loaded c.o.a.l. of 3.65 inch with the smk's due chamber limitations and 3.75 with the Bergers because thats all my Wyatt's magazine will hold. Does anyone have any experience with how much more powder can go behind a Berger to get the same pressure signs? And what is the resulting velocity? These bullets are designed very differently from the diameters to the lengths and mostly the length of the bearing surface.