Home Forums Hunting & Shooting Ask The Gunwriters 7mm Mauser article by Koos Barnard

Jamesjr,

Have pointed this out before, both here and in magazine articles and books, but one of the difficulties in handloading for the 7x57 is that like a lot of military cartridges developed before 1900, throat lengtsh vary considerably. Most throats from that era were VERY long, to accomodate the very heavy round-nosed bullets almost universally used in early military rifles.

Once the switch to lighter spitzers began, throat lengths were shortened up in some military rifles, the reason the .30-06 replaced the .30-03, and .30-06 throat lengths have been standardized ever since. But the throats in rifles chambered for many other old military cartridges still vary enormously, and the 7x57 is one of those rounds.

I've owned a pile of 7x57's over the years, from old military rifles to modern sporters to recent custom rifles. Have seen the original super-long military throat in rifles made in the 1990's, and short "sporter" throats in rifles made before WWII. Which is exactly why exactly how much powder (as an example let's use IMR4350) it takes to reach a certain velocity varies enormously. I've owned 7x57's with 21-22" barrels that would get 2900 fps from 139-140 grain bullets with only 46 grains or so, and others that needed 50 grains. Which is no doubt why Jim's suggested "over charge" of IMR4350 only got 2600 in your barrel.

Will also note that an editor who worked with Bob Hagel says he bulged the chambers in more than one rifle while working up loads, a sign of high pressure far more certain than those used by most handloaders.

I just settled on 150 gn core-lokt over 50 gr of ar2209 for 2700 fps in the old Brno 21...the same load gave a neat 2800 fps out of a square bridge Waffenfabrik Oberndorf.

I mucked about with Nosler and a couple of other projectiles but stayed with the Remington as they cost $20 per 100 at the time and were great fun on rabbits.

I have since moved on to 7x64.