I have a Ruger #1 International (aka "RSI") in 7x57 that shoots VERY accurately from a COLD or luke-warm barrel, but I have to wait after each shot for the barrel to cool back down before shooting the next shot if I want good groups. Apparently, all that wood around the barrel makes for some inaccuracy as the barrel heats up.
My RSI loves H4350... the "sweet spot" or "accuracy load", using a 140 grain Sierra ProHunter, flat-based bullet, is 47.2 grains to 47.6 grains of H4350 yielding an average muzzle velocity of 2570 fps. Sparked by standard Winchester large rifle primers in Remington cartridge cases, my little RSI puts 3 rounds into .176" (47.2 grains) to .179" (47.6 graisn) at 50 yards where I do most of my .22 rimfire and .50 caliber flintlock shooting... never tried it at 100 yards.
I put a fairly powerful scope on the little RSI... a 4-12x40mm Bushnell "Legend" scope with an adjustable objective turret so I can eliminate parallax. The "Legend" is a mid-priced scope of good quality and gathers 91+% of the available light while yielding clear, sharp images. I'm sure this scope helps in the "accuracy department".
The maximum load, using 50.0 grains of H4350, put 3 rounds into .404 inches at 50 yards. However... recoil and the noise-level were both "up" considerably. While I haven't chorongraphed the maximum load, I did chronograph most loads below the maximum load and am estiimating that the max load out of my RSI's short 20-inch barrel was in the area of 2785 fps with a 140 grain Sierra bullet... more than enough power for the biggest whitetail that ever lived.
The secret to accuracy with a RSI is allowing the barrel to cool down, but one must remember, the RSI is a
HUNTING RIFLE, not a bench-rest rifle!!! Other RSI owners I've talked to about "accuracy" agreed that their rifles shot best from a cold or at least no hotter than a luke-warm barrel and, of course, a "cold" barrel is what we have in most hunting situations, so how can that be "bad"?!?
Even from a hot barrel, the little RSI's will shoot at least a "
minute-of-deer"!
Strength & Honor...
Ron T.