A buddy asked me to post this for him as he's having a hard time registering.

I have a Kimber Montana in 7WSM and want to re barrel it to a 6.5 caliber. My intended use is occasional 1,000 yard target and LR hunting. I have read everything I can find and am more confused than ever. Does anyone know how to break the tie between the different options? 6.5 WSM, 6.5 WSSM, 6.5RSUM, 6.5X 284 or any of the AI offerings. Thank you for your help.

I just finished putting together a a 6.5wsm in a Savage long action, still haven't shot it yet .... looking for load info on 140g SMK using retumbo or h869 powder. I got my dies from Lee for under $30

6.5-284 has dies and brass available off the shelf. If you choose any of the others you will have to form the brass while it is not difficult to neck brass down a little if you choose the saum you will have to use brass from Remington and it has a bad reputation with a lot of reloaders.

First off, I am not a gunsmith, so my info may not be valid.
But......If you are planning to rebarrel your Kimber WSM, I am pretty sure the 6.5x284 is out. That case has a .473 rim diameter, much smaller than that of the WSM/SAUM/WSSM family of cases. This will also go for any AI'd case made from "standard" cartridges- virtually all of them have the .473 bolt face.

That said, I have heard good things about the 6.5 WSM and WSSM variants. I would lean towards the WSM case as a start point, though, instead of the WSSM. I think you'd be up for some feed issues due to the WSSM's significanlty shorter case, unless you devise a way to shorten your magazine and follower.

I have not yet seen any mention of the 6.5 SAUM on the net, so cannot offer any insight into it's performance, feed, function, etc.


Were it me, I'd keep the Kimber as is -I'm not sure you'd have much of a significant gain in performance between it and a 6.5 WSM. Then I'd pick another gun up to make into a long range rig.


SBB

GSSP-

Ditto what Bon Bon said. If you are going the way of rebarreling to 6.5/.264 on that rifle, I would highly recommend the 6.5 WSM.

I love my 6.5 WSM; it's incredibly accurate. I had mine built when all there was in the way of brass was .300 WSM brass which made necking down from .300 to 6.5 a bit tedious and challenging. Now you have .270 WSM Brass thus, necking to .264 is a snap.

61-63 grains of Reloader 22 behind 140 grain bullets.

Good luck!