I have a 1993 Ruger #1 International (aka "RSI") in 7x57mm and love it. The whole rifle is only 36-inches long including that 20-inch barrel.
My RSI loves H4350 rifle powder as do a good many #1's in 7x57... and since the ammo manufacturers vastly under-load the 7mm Mauser cartridge, you should be a handloader to take full advantage of the fine 7x57mm cartridge.
The maximum load for a "modern rifle" (according to a well-known reloading manual) is now 50.0 grains of H4350 using a 140-145 grain bullet with a pressure rating of 50,000 CUP... up from the prior "maximum load" of 46,000 CUP.
The 46,000 CUP limit is/was due to a lot of the old, weaker 1893 and 1895 Mausers, which are also chambered for the 7x57, that are still being used in a great many 3rd world countries. With an extremely strong action like the falling block action used in the Ruger #1's, 50,000 CUP isn't a problem. That's the same pressure to which a .30/06 is normally loaded.
My RSI has fired 3-shot groups measuring .176 inches at 50 yards using a "target load" of 47.2 grains of H4350 behind a 140 grain Sierra, flat-based ProHunter bullet sparked by a standard Winchester large rifle primer in once-fired Remington cartridge cases. A slightly heavier load (47.6 grains of H4350) fired a .179-inch, 3-shot group with the 4-12x by 40mm A/O scope set on 12x and the parallax adjusted out using the adjustable objective turret.
At maximum load (50.0 grains of H4350 behind a 140 grain bullet), recoil and muzzle blast are up considerably, but accuracy is still good... .404 inches (3-shot group @ 50 yards). Muzzle velocity is close to 2800 fps out the the RSI's short, light and handy 20-inch barrel.
The downside of that light barrel in a Mannlicher-style stock is that the barrel heats up quickly & easily and takes a bit of time to cool down again.... and at least with my RSI, I must allow the barrel to cool down to just "warm" if I want it to "group" well. If fired repeatedly without being allowed to cool down to just "warm", the rifle's "groups" open up considerably.
I've been advised by a good many other shooters and friends to try to "relieve" the wood around the barrel and "do this or that" to it to improve it's "hot-barrel accuracy". But I've opted to leave it alone and be patient when shooting the RSI when I shoot it off-the-benchrest since any shot at game will be out of a
COLD barrel and will thus be very accurate just as the rifle is at this time... and with a single shot rifle, how many accurately-aimed rounds can a man get off at one game animal?
Of course, if a man places the first shot in the game's "vital zone", he won't need more than one shot, will he?!? N'est pas?
Of all my big game rifles, my Ruger #1 RSI in 7x57 is my "
favorite" and will handle any game in the "new world" short of the "big bears" ... and I bet a good many #1 RSI owners feel the same way about their rifles as well.
Strength & Honor...
Ron T.