The 7x57 is vastly under-loaded by American ammo manufacturers due to the SAAMI chamber pressure rating of just 46,000 CUP. This is due to the number of old, weaker 1893 and 1895 Mauser rifles still being used in many 3rd. world nations.
When handloaded to its full potential (the published maximum load of 50.0 grains of H4350 behind a 140-145 grain bullet), the 7x57 Mauser yields slightly greater muzzle velocity and bullet energy than the very popular 7mm-08 Winchester which is based on a necked-down .308 Winchester case. The 7x57 has a slightly greater powder capacity compared to the 7mm-08.
The accuracy load in my Ruger #1 International (aka "RSI" with a 20-inch barrel, Mannlicher-style stock) is 47.2 grains of H4350 behind a 140 grain Sierra, square-based ProHunter bullet sparked by a standard Winchester large rifle primer. This load yielded a 3 shot group (at 50 yards) of just .176 inches and an estimated muzzle velocity of 2540 fps.
A slightly heavier load (47.6 grains of H4350) yielded a 3-shot group of just .179 inches and a chronographed muzzle velocity averaging 2580 fps which would serve as a fine deer load with excellent accuracy and very little recoil.
My hunting load (and a
MAXIMUM powder charge according to a popular handloading manual) is 50.0 grains of H4350 behind a 140 grain Sierra, flat-based ProHunter bullet sparked by standard Winchester large rifle primer. This load yielded a 3-shot group measuring .404 inches (at 50 yards) with an estimated muzzle velocity of 2780 fps.
Both muzzle blast and recoil of my hunting load were "up" considerably from the accuracy load mentioned above. I tested probably 2 dozen different loads in my 7x57 using H4350 and every one of them was at least a "minute-of-deer". Therefore, I concluded that H4350 was "
THE" powder for the 7x57 in MY rifle.
I didn't arrive at that conclusion using any "short-cuts". All-in-all, I tested 4 different bullets (140-145 grains) together with 4 different primers and 3 different powders over a two year period as well as a great many different bullet-seating depths... something relatively easy to do when shooting a single-shot rifle like the Ruger #1 International.
Handloading is a great hobby... and I enjoy it almost as much as shooting. I've spent many, many happy, contented hours at the loading bench developing different loads for different rifles. "Accuracy-is-king"... ALWAYS, so I go with the best accuracy I can get with a fairly heavy load for hunting... but for just "fun shooting", I go with "THE" most accurate load without any concern about muzzle velocity or bullet drop.
BTW, H4350 is one of Hodgdon's "EXTREME" powders meaning that Hodgdon claims their EXTREME powders are
not effected by air temperature... a decided advantage for a hunter who develops his hunting loads in the heat of summer, but shoots them at game at a much colder temperature which considerably lowers the muzzle velocity of powders that ARE effected by air temperature.
My advice to you, my friend, is to go with the 7x57 and get into handloading, not only to cut your ammo cost by 2/3rds to 3/4ers and end up with considerable more accurate ammo (than factory loaded ammo) specifically loaded for your individual rifle.
If you plan to do a lot of shooting, I'd suggest you buy 200 new Winchester (Remington brass, if Winchester brass isn't available)"virgin" brass in 7x57, a pound or two of H4350, a 1,000 Winchester large rifle primers, a standard RCBS reloading die set in 7x57 and consider RCBS's reloading "package" which includes their single stage, high quality reloading press, 505 powder scale and a good many other needed tools.
Try to find a "reloading mentor"... someone with years of reloading experience to help you get started and advise you as to what other "tools" you'll need like a set of dial or digital calipers which will prove invaluable-check the local pawn shops for a used tool... you can often get a high quality $200+ digital or dial caliper (cost new) for $20-$40 at a pawn shop.
Jus' my 2�...
Strength & Honor...
Ron T.