Re: 300 Norma Mag std VS Improved - 3200fps A-max?
300 RUM is based on a magnum boltface, while the 300 Norma Magnum is built on a 338 LM boltface, using 338 Norma Magnum brass that has been necked down to 30 cal - they now have 300 Norma Mag headstamp brass. As a result one uses a 338 LM action the other a standard magnum action (I know folks build 338 LM on a magnum action, but I'm not one of them). My memory may be failing me, but my research reflected teh 300 norma mag case capacity right at 105-108 grains of water and the 300 RUM something around 112-115 grains of water.
The 300 Norma was designed to accomodate the 300 grain sierra 338 without much impingment on the case capacity and still fit into a standard 338LM magazine. If oyu put a 300 grain 338 pill into the RUM equivelent brass and then seat them into a LM magazine, you eat up a bunch of case capacity with the bullet.
Yes Jimmy loves the 300 Norma, much better than the 338 version.