I've got a Ruger #1 RSI in 7x57... it's a "sweet" little rifle. Mine "loves" H4350 rifle powder at just about any load level right up to the maximum load of 50.0 grains. I haven't chronographed that load yet, but I'd guess it will be about 2775 fps... maybe up to as much as 2790 fps or 2800 fps, but that may be "wishful thinking" due to the RSI's short, 20-inch barrel.
The most accurate load of H4350 I've found so far is 47.2 grains which yielded a very "tight" 3-shot, "clover-leaf" type group @ 50 yards measuring just .176 inches as measured by my digital calipers and a .179 inch "clover-leaf", 3-shot group, shot the same day (6/5/07) using 47.6 grains of H4350 at 50 yards.
Even the maximum load of 50.0 grains of H4350 yielded a 3-shot group @ 50 yards of just .407 inches. Recoil is noticably higher as was the sound level of the shot... but still not "objectionable". However, this heavy load (50.0 grains of H4350) is ONLY for "MODERN ARMS IN EXCELLENT CONDITION" !!! The load generates 50,000 C.U.P. ... considerably greater than the SAAMI's recommended chamber pressure of 46,000 CUP.
Obviously, this rifle's "sweet spot" ranges from 47.2 grains to 47.6 grains since the groups "open up" slightly beyond 47.6 grains or less than 47.2 grains of H4350 powder with a 140 grain Sierra ProHunter, flat-based bullet in Remington cases sparked by standard Winchester primers.
However, in order to shoot such small groups, I had to allow the RSI's barrel to "cool down" to "barely warm". To shoot the RSI when the barrel is hotter than that will probably larger, more scattered groups.
But then... when hunting, it is common to shoot game using a COLD barrel... and I've found my RSI shoots the same using either a cold, cool or slightly warm barrel since the barrel apparently doesn't begin to touch the fore-end wood of the Mannlicher-style stock until the barrel heats up to "warm or very warm".
Strength & Honor...
Ron T.