XM-3 Magnum?


Full Member
Sep 14, 2008
Saint Paul, Minnesota
Hi all,

I recently finished my SASS build, and I'm looking to get some ideas for my bolt gun build. So, here come some questions:

I've a Remington 700 SPS in 7mmRM. That's the donor.

I plan on using it for paper punching out past 600 meters, and against anything bigger or scarrier than a white-tailed deer.

My initial thought was to make it very similar to an M40A5, but I've been reading about and admiring the XM-3 quite a bit. I like the one Lowlight totes around, and I really like how handy they are. . .

So, if the XM-3's 18" barrel drops about 200fps from the longer M40 barrel (just the guesses I've read on the inter-webs) . . .

So the question is this, how short can I go with a magnum cartidge? I'm rebarreling, so I can chamber almost anything. I just want a bit more umph than I get out of my SASS.

Is it possible to do q short magnum? Maybe a wsm with a 20 or 22 inch barrel?

As always I really appreciate being able to tap into the vast knowledge floating around here!


Full Member
Feb 14, 2010
Two Rocks, Western Australia
Re: XM-3 Magnum?

I have heard that a 22" bbl with a 300WM is the shortest you want to go. I dont think you should go as short as you can with the 308. With the 300WM you have a lot more powder to burn and a heavier bullet.