If you're planning to handload .375 RNE for your Mauser, you'll have greater flexibility with projectile choices than you would with a Mannlicher Schoenauer.

The Schoenauer magazine performs flawlessly and with impeccable reliability when fed with uniform cartridges that conform very closely to the Eley drawing posted above. Changes in bullet profile or cartridge OAL can cause jams. The stacked magazine of the Mauser is not so particular.

I have a few boxes of 9.5X57 that were loaded (by someone else) with semi spitzers that I can load singly or by two in the magazine. Loading a third jams it. I'll either pull the bullets or just shoot them out by twosies while sighting in.

If you come across any of the now virtually extinct Hornady 3715 (270 grain RN) projectiles at this point in time you could likely trade them (at a rate favorable to you, if desired) to an M1910 shooter for whatever other .375 he may have or even 9.5X57 cartridges loaded with bullets other than 270 RN.

Properly sized new brass is available from Quality Cartridge (Qual-Cart). I have some. It measures right, haven't loaded any yet. If you'd rather reform other brass the .35 Whelen is an excellent 'donor case'. The plentiful .30-'06 works every bit as well, yet sizing to .375 takes more work. Either case, of course, is longer than 57mm and needs to be cut to proper length.

Midway Qual-Cart