I love IMR and H 4831 for my 300 win mag. Just ran some tests the other day with some 180 gr Barnes X flat base using 71, 72, 73 gr H 4831. Velocities were a bit low - a little over 2800 fps - but fantastic accuracy at 100 yds - .75 to 1 inch. Now I have to see if I can up the velocity while maintaining accuracy. May try the coated flat base or triple shock next.
My pet load has been 72.5 to 73 gr of IMR 4831, CCI mag rifle or Fed 215 primer, Rem cases avg wt 235-238 gr/case with 180 gr Noslers Partitions, or Speer Hot core. It gets about 2900-2950 fps at 50 degrees F 24 inch barrel. I can get more velocity but this combo has put down close to 20 caribou and a couple moose. I'd say my long term avg group size is 1.25 at 100 yds and from the bench. Note my gun was chambered by H-S Precision and allows a much longer OAL than the factory ammo. It lets Nosler partitions be seated to about 3.45 to even 3.55 OAL. So if you must seat your bullets deeper to chamber in your gun approach my loads carefully.
H 4831 can work just as well but you need a grain or two more to get the same velocity- check the books. I can get more velocity with the IMR than with the H - I think I have reached over 3,000 fps with the IMR but choose to keep velocity down a little for accuracy and less meat damage.
From my observations of other guys using Sierra bullets on caribou, I'll stay with Nosler Partitions, especially if moose are in the picture. I've had very good performance with the Hot Cores too and that surprised me but I'm happy with em. I don't choose to use them on moose though. My rifle doesn't seem to like Hornady 180s for some reason. Haven't tried Balistic tips. For practice the bulk Rem Cor Loks work ok.
Sierras are wonderfully accurate - I've burned up a lot of the 168 and 165 grainers in this gun but I've always felt the caribou I shot were more certainly anchored than the ones my friends shot with Sierras. I abandoned 165 gr bullets (Speer grand slam and Nosler Part) at about 3100+ fps due to excessive meat damage.
I am exploring the Barnes X and Failsafe bullets in 180 as they might be a little better if I stumble onto a brown bear.
I have gotten good results with the 4350 powders but like the slightly slower burning of the 4831s. You might want to look at Reloader 19 and 22 as well but they aren't available to me so I have tried them.
HTH
