My
best 3-shot groups @ 50 yards with the scope set on 12x and the A/O adjusted to eliminate parallax out of my 7x57 Ruger #1 International (full Mannlicher style stock) with a
20-inch barrel and a Kepplinger single set trigger using H4350 behind a 140 grain Sierra ProHunter flat-based bullet sparked by a standard Winchester primer in accurized Remington cases were as follows:
47.2 grains = .176" (accuracy load)
47.6 grains = .179" w/MV of 2578 fps (accuracy load)
50.0 grains = .404" w/est. MV of 2780 fps (Hunting load)
The Ruger #1 International (aka "RSI") "likes" H4350 powder. All groups fired using H4350 were relatively small (less than a half inch at 50 yards), but recoil and report were up considerably at the maximum load of 50.0 grains of H4350.
THIS IS A MAXIMUM LOAD FOR MODERN RIFLES ONLY.All bullets were seated out to within 10/1000" of the rifling.
Hodgdon H4350 rifle powder is one of Hodgdon's "EXTREME" powders meaning it is not "temperature sensitive". Therefore, you should get about the same muzzle velocity regardless of the air temperature. Many hunting loads are developed in the heat of the summer or in the warm autumn weather, but used in much colder temperatures during hunting season.
Therefore, the EXTREME powder has a great advantage over other powders, many of which
ARE sensitive to air temperatures and will yield considerably
less muzzle velocity in cold weather compared to a hunting load that was developed in warmer temperatures earlier in the year.
I hope this information helps you.
Strength & Honor...
Ron T.
