The 7x57 Mauser is one of my all time favorite rounds. Currently I have a Ruger #1A, Wincherster M70 Featherweight and a custom Mauser all chambered to the 7x57 Mauser round.
I expect I'll get a bit of static on what I have to say but Kimber imported a bunch of 1893 (93) Mausers that had been rebarreled to 7.62 nATO.

Now hese are Spanish mausers which for some reaon have a bit of a poor reputation. Spain's assualt rifle was chambered to the 7.62 CETME cartridge which has the exact same dimensions as the .308 Win./7.62 NATO. However, the CETME round was loaded to a significantly lower pressure and the military CETME rifle had problems with full power NATO ammo. Anyway, Kimber imported these rifles, put them in, I believe Ramline stocks, altered the bolt handles and drilled and tapped them for sccopes. They did have the rifles proof tested by the H.P. White Laboratory to assure their safety with .308 Win. Ammo.
The 93 Mauser is easily identified by looking at the front of the bolt. The bolt face will be flat on the bottom. The 95 will be round on the bottom like most conventional bolt actions. The 93 has no safety third lug while the M95 is supposed to use IIRC the root of the bolt handle as a somewhat safety lug.
Years back, I once owned an M93 Mauser made at the Oviedo Arsenal in Spain and was date stamped 1916. Some small British gun shop at one time made it into a neat light weight sport along the style of Rigby. Because of the "supposed" weakness, I never loaded ammo for that rifle over factory specs. I guess one of my dumbest moves was selling that rifle.

I killed a lot of deer with it. One of the best bullets I ever found was the Sierra 170 gr. round nose. very accurate and even at 2300 FPS would really knock a deer down, especially in the rain forest of Northwest California when I hunted there a very long time ago. Sadly Sierrra does not make it anymore.
In current factory ammo, I've only shot the Winchester 145 gr. Power Point and the federal 175 gr. round nose. The Winchester is very accurate in my rifles, sub-MOA in two and just a hair over MOA in the Ruger. I don't think the Federal is delivering anywhere near factory advertised velocity and I'm sad to say while I've only lost two deer in my hunting career, one was shot with that Federal load. Whether it was a box of bad ammo or federal just ain't loading them to spec I can't say but when I finally got a chronograph, the rounds that were left over from that box averaged 2100 FPS. Not good.
Well all I can add is properly handloaded the 7x57 is an excellent round. Loaded with a good 140 gr. bullet deer are in trouble. a premium 150 to 160 gr. bullet and elk better run. With a stout 175 gr. bullet, even the great bears would be in a tight spot provided the shooter kept his cool and placed the shot as precisely as possible. That's what worked for Bell. He preferred brain and heart shots whenever possible and IIRC, the 7x57, or .275 Rigby as he called itwould do the job. FWIW, I've also seen a rifle marked .276 WR for Westley-Richards but it too was a 7x57. One of the world's great rounds.
Paul B.