The problem with the .300 Win Mag is the fact that if you seat bullets in deep enough to fit the magazine in most rifles, you are a long, long ways away from the rifling. My Winchester Laredo is like this. Bullets in far enough to load the magazine? Expect about 2 1/2 to 3 inch groups at 100 yards. Use a tailored handload that the rifle likes? Oh, my gosh!!
My load (safe in MY rifle, work yours up carefully):
New Winchester cases
175 grain Sierra MatchKing
70.0 grains, IMR 4831
Federal STANDARD Match Primers
Seated to a COL of: 3.510 inches, no crimp
Measured group: 3 rounds into .384 at 100 yards; five rounds into .468 at 100 yards.
Rifle: Winchester M70 Laredo
Glass bedded, everything else box stock
Scope: Simmons (yes, I said Simmons)8-32x44
Good luck with your rifle!
------------------
"Be not afraid of any man, no matter what his size;
When trouble rises, call on me and I will equalize."
My load (safe in MY rifle, work yours up carefully):
New Winchester cases
175 grain Sierra MatchKing
70.0 grains, IMR 4831
Federal STANDARD Match Primers
Seated to a COL of: 3.510 inches, no crimp
Measured group: 3 rounds into .384 at 100 yards; five rounds into .468 at 100 yards.
Rifle: Winchester M70 Laredo
Glass bedded, everything else box stock
Scope: Simmons (yes, I said Simmons)8-32x44
Good luck with your rifle!
------------------
"Be not afraid of any man, no matter what his size;
When trouble rises, call on me and I will equalize."