But they didn’t shorten anything. Power, acâ¦ That was the 7x57mm re-branded for the non-metric British Rigby rifle. Mag. I am ordering a 33 nos reamer for the 250 bergers, which kill like crazy by the way. This compromise should account for the slower muzzle velocities many rifles produce with factory loads and safe handloads. And the if the numbers Nosler has provided on the two variants itâs releasing are on the mark, there is little arguing the cartridge has plenty of snap. 1:10 300 WSM 24 in. Mag. Because the 7mm RM is a familiar benchmark, let’s establish some basic performance numbers in an 8 pound rifle with 24-inch barrel spitting a representative spire point, boat tail, 175-grain hunting bullet, B.C. I am planning on using the 195 Berger's at around 3050-3100 FPS. for my brand of hunting. PX Member. Crown dent could be problem also. Is Handloading Rifle Ammunition Really Worth It? 1:10 HuntPost.com, Inc. All rights reserved. Like most of our early magnums, this is based on the belted .375 H&H Magnum case. Ron Spomer. You already have a Mashburn....what more do you need? I believe to get the most benefit out of the 28 nosler you need to have it chambered using a custom reamer with a longer throat to be able to utilize as much of the case as possible with the heavy for caliber bullets. Moose by the dozens have fallen to the 7mm Rem. I believe to get the most benefit out of the 28 nosler you need to have it chambered using a custom reamer with a longer throat to be able to utilize as much of the case as possible with the heavy for caliber bullets.