I just bought an early Ruger RSM in 375 H&H. I had one of these before so I know that it's very heavy for a 375.

Anyway, I'll soon have this very heavy .375 that I need to do something with. I have a .375 Ruger and do not need two .375s at this point. I've heard of people having these rebored to bigger calibers and keeping the original barrel because of those beautiful express sights. What can I have this rebored to, and who is able to do so? What can I do with this rifle? 500A2? 470 Capstick? Would prefer to have something that the rifle is not factory chambered in, so no 458 Lott or 416 Rigby.

Thanks,
Rob

BUFAF, Check out this thread on the 404/375:

http://forums.accuratereloadin...1043/m/660101779/p/1

How about a 416 Hoffman?

Perhaps the .375-404 Jeffery Saeed?
k

Based on what some other folks here on AR have done with the older RSM's, you should be able to go up to .510 if you want. Keep in mind that many of the larger cases will require a new magazine box and follower,as well as opening up the bolt face and feed rails.

Dan Pederson ( 928-772-4060 ) and Clearwater Reboring ( 509-684-5855 ) specialize in reboring and could probably answer any questions you might have.

470 Capstick is a nice cartridge, George, the moderator has one

Well, Bufaf,
you are up against some constraints.

1. First, you have a great all-around rifle in 375 Ruger. If things go badly with the rebore you will still have a rifle for some hunting.

2. The muzzle diameter of the H&H may limit your options. Simply measure the muzzle and subtract .0.3" to find the recommended limit.If the muzzle is .75" then your rebore limit will be .45. You will need .77" or .80" in order to think about a Capstick or a 500 Mbogo.

3. If you are going bigger with a H&H action/magazine combo and don't want a Lott, then the Rigby family can be your target: 450 Rigby (or Dakota), 470 Mbogo, 500 Mbogo. All are great cartridges, pick the one that will fit in the old barrel. A good gunsmith can open up the bolt and rails and adjust the extractor for not too much extra.

4. To go just a little bigger than .375 you are looking at 416Rem and 416Rigby, two great cartridges, but with factory competitors. (Or substitute the 416 Weatherby for the Rigby.) If you reconsider and go this route, then consider handloading a 416Rigby to its natural potentials. Loads should produce 6000 ftlbs +/-200. Quite versatile with the right bullets from 300gn to 400gn, 2600fps to 3000fps. At least such loadings would not be a factory combo.

It's unusual to rebore a barrel - I checked with Lilja once and they refused. Moreover, they had no recommendations of where to get it done. Besides likely just as cheap, if not cheaper, just to rebarrel your gun in caliber that will work well in your action and with your bolt face.

With minimal bolt fact work, one might consider a 416 Dakota, or use you existing bolt with a 416 RUM conversion.

PM me, if you want to build a 416 RUM (aka, 416 Ultracat).

Regard, AIU