I have a winchester 70 and am looking at getting a caliber change before too long. It's the 300wsm short action. Are there any other calibers that I could convert it to that are better for long range shooting (mainly paper/target)? I just don't know if the bolt face will work for other calibers or not. From what I see it looks like 300wsm is good for long ranges though

There are other rounds you could convert it to. That said, I woudln't unless you've shot out the barrel already or are having other issues with it. 300WSM is plenty good for long range shooting (at least out to 1k). If you can get a 190 VLD to 2900-3000fps, you've got a killer setup for long range shooting.

The bolt face and action size will limit you to other WSMs, RSAUMs and WSSMs unless you want a wildcat cartridge. 7 WSM, 7/300 WSM and 7 SAUM are used a lot in benchrest shooting.

I would stick with your 300 WSM and push a 190 grain bullet for your long range stuff. get a rail and rings with a good scope to dial for your elevation, and practice with it. If it will shoot under moa, then it will work.

In your M70 ShortAction Magnum you have couple choices ...A. Just using your bolt face of .535 on either what you already got in 300WSM or some other stock cartridge ...or sending the gun to someone like Charly Sisk in Dayton Texas.

Mr Sisk is noted for building wildcats on the 300WSM & .535 magnum bolt face, and without going into too much detail, you could come up with mebbe a 6.5x300WSM for a great LR caliber that won't kill your shoulder and will mebbe outrun a 6.5x264Win or 6.5x'06 AI, or some other exotic WSM/RCM based caliber to play with.

I'd like to have a 9.3 B-S made up. In laymans terms that is a 9.3 (aka.366 bullet diameter) on a 300WSM case and called a 9.3 Barsness-Sisk. Designed by John Barsness and built by Charly Sisk. Bigtime More MV than a 9.3x62 in a shorter stiffer receiver and close to a 9.3x64 Brenneke, .370 SAKO Mag (.366 x 66mm) or 375 H&H in 260's in a 7+lb rifle pounding TSX or NAB 250gr'ers at 28/2900 fps out of a 24" barrel. Different Strokes than a Long Range paper shooter for sure. With Charly Sisk, your imagination has already prolly been built when it comes to SA Mag's.
Cheers
Ron

This exactly.

X2 on sticking with it. I've been wanting to build a 7wsm but the std size action for the wsm isn't long enough for the high bc bullets. The 300 win mag and wsm are almost identical and the win mag is a proven 1k caliber. If you don't care about the expense of a barrel burner go with a 6.5 wsm based off the 300 wsm casing. It's a screamer and a guy I know has one on a 28" tube and he can shoot those high bc pills accurately a very long way. But as mentions before don't give up on the 300 just yet.

My days of running more than 50 rounds per shooter in anything over a 270WCF in a bench session are long gone. So if I can get 5-600 rounds out of a Magnum Boomer's barrel at my age and state of grace I prolly won't live any longer than that anyway.

Sounds like the 6.5x300WM just might be the ticket if the old New Haven FWT Whizzum I picked up won't shoot straight enough for Minute of Deer at +500 yards. Got a SAKO 260 I'm starting to work up for the sub 500 yard stuff...
Ron