Ruger RSM conversion to .505 Gibbs

[rhoward252]

Hello Gentlemen,

I am new to the site. I'm also not a genius gunsmith. I'm a guy that loves guns. I went on a plains game safari in S.A. last September and have been bitten hard by the Africa bug. I'm ready to chase dangerous game. Or at least I'm confidently ignorant. I have RSM examples in (all 3) .375 h&h, .416 Rigby, and .458 Lott. I have a Browning Safari in .375, an FM Mauser in .458WM, a custom rifle in .375 Ruger and an African in .416 Ruger.

I happen to have a spare RSM in .458 Lott and would be curious about converting it to .505 Gibbs. There are several historic postings about this but many of the referenced companies have sold/merged/gone out of business. If anyone has any recent experience or knowledge in this area, I would appreciate your guidance, as I'm starting from scratch and don't know what I'm doing but am intrigued by the big .505. I would prefer a rebore to keep the original barrel. From what I've seen, I believe that the bolt face would need work as well. Quality resource information is appreciated.

As a side-note, a lower-end .500 Nitro double rifle is always on my radar if anyone knows of any. Not interested in guns over 20k. Not that I can afford 10-15k but it is a more realistic fantasy than 20k. Thanks for enabling me in advance. - Jake.

 

[sierraone]

Contact @ActionBob with these questions.

 

[Mark A Ouellette]

@rhoward252 I would NOT rebore from .458 to .505 diameter. The gun will probably shoot fine but it will have a light 505 Gibbs barrel.

I'd want more weight to the barrel to reduce both recoil and muzzle climb.

 

[ActionBob]

Mine is a rebore. It only holds 2 rounds down. If you chamber a round, you can open the floor plate and stuff 2 in the magazine but it is very tight and feels poorly so not a great option. I had two down when stalking my rhino and empty chamber as I was crawling behind the PH. At the moment of truth I chambered a round, sat up and shot twice, reloaded and got a 3rd shot in. First shot was perfect heart/lung but solids so even with a .505 hole, not the devastation of a TSX for example. Solids were the law.

The gun is lively and compared to my CZ in 505 Gibbs it is light and lively, stock is not as well designed ar least to fit me. LOP is short so I added a skip on pad over the limbsaver it has on it.

Five guns were done from 416 Rigby's from what I have been able to learn. By a shop in Alaska.

 

[colorado]

I would sell your RSM and just buy a CZ in 505 Gibbs assuming you can find one. Or buy one from Wayne at AHR.

 

[ActionBob]

I would sell your RSM and just buy a CZ in 505 Gibbs assuming you can find one. Or buy one from Wayne at AHR.

Unless you really want one in an RSM for reasons other than having a good functioning rifle. I agree. Buy a CZ, or a gun built on a CZ. Possibly a Montana or MRC. Or spend more money and get a Dumoulin

 

[colorado]

ooh Dumoulin .... I wish

 

[rhoward252]

Mine is a rebore. It only holds 2 rounds down. If you chamber a round, you can open the floor plate and stuff 2 in the magazine but it is very tight and feels poorly so not a great option. I had two down when stalking my rhino and empty chamber as I was crawling behind the PH. At the moment of truth I chambered a round, sat up and shot twice, reloaded and got a 3rd shot in. First shot was perfect heart/lung but solids so even with a .505 hole, not the devastation of a TSX for example. Solids were the law.

The gun is lively and compared to my CZ in 505 Gibbs it is light and lively, stock is not as well designed ar least to fit me. LOP is short so I added a skip on pad over the limbsaver it has on it.

Five guns were done from 416 Rigby's from what I have been able to learn. By a shop in Alaska.

Bob, have you seen any of the issues with the rebore that Mark suggested as a possibility? I'm guessing any .505 Gibbs is lively, as you put it, but do you feel that the rebore is a substantial net-negative over a rifle that was born as a .505? Your experience with limited-round fitment in the magazine is noted. Thanks for the input.

 

[ActionBob]

Bob, have you seen any of the issues with the rebore that Mark suggested as a possibility? I'm guessing any .505 Gibbs is lively, as you put it, but do you feel that the rebore is a substantial net-negative over a rifle that was born as a .505? Your experience with limited-round fitment in the magazine is noted. Thanks for the input.

Of course the rebore takes metal out of the barrel so it is lighter. Not sure if it's possible but consider putting a small mercury tube in the forestock and a larger one in the stock.

I put a strap on Murray leather cartridge holder on the stock to add the weight of 6 rounds, considerable with the 505 Gibbs. The CZ is a better designed 505, but the RSM is more unique. It's all about what you want.

 

[AZDAVE]

@ActionBob I have used tungsten powder that is used to weight golf clubs mixed with epoxy to weight the forend of stocks to get the balance right. I have just drilled a small shallow hole and filled with the epoxy/tungsten powder mix. Could also use lead powder.