I'm thinking about picking one of these up, but would really like to be able to use 200 or 220 grain bullets in .30 cal. Has anyone had any luck with reloading these in the larger bullets, and were you able to get pretty good groups with it?

While I haven't actually done any reloading for the .300 WSM, I would expect that overall length concerns would be at the top of my list. Will your magazine box let you seat the bullet out to where the bullet isn't pushed far backinto the case - limiting powder capacity and driving pressures up? How about the throat of the barrel? If the magazine box isn't an issue, is the throat long enough topermit seating out to where the base of the full diameter bullet is about even with the base of the neck? Twist isn't usuallythe limitingissue - a 1:12 will stabilize a 200 grain Matchking easily. A 1:10 (standard for the .300 Win Mag) will stabilize a 220 gr. Matchking.

I have had no trouble getting decent accuracy with Hornady 220-grain round-nose bullets from a Win. M70 in .308 Win, which has a 1/12" twist. This twist may be too slow for a LONG pointed 220-grain boattail, but it is OK for the shorter, RN version. My load was 48 grains of Norma N205, MV around 2300 FPS. Great VA swamps deer load!

Loading for both the 300 WSM and 300 Winmag, ballistically they are identical up to 180 gr bullets. Above that is where the full size mag outperforms. You'll probably be able to go to 200 gr before seating depth becomes an issue. The only way to know is to try them.

I like the Remington SP bullets... What bullet could I reload that would perform like the rem Sp bullet???

You should be able to get the Remington bullets at Midway.

Roscoe hit the nail on the head as usual. I loaded 200 gr. Nosler partitions to 2800 FPS in my 300 wsm. I seated them as long as the Mag would allow. Even so the bullet was seated well into the case infringing on the powder capacity and causing a substantial bullet jump into the lands. with all that being said my factory Browning A-bolt would really shoot. I shot a few 1/2 Inch groups at 100, andone .6 group at 200 yds.It was so impressive thata buddy wanted it so bad that he paid double what it was worth.