I'm thinking about rechambering my Whitworth Express 458Win to 458 Vincent Short. I talked to Ted Blackburn and he has a wider magazine box that will hold four rounds.

Is there anything else that needs to be done besides rechambering?

Is the Vincent Short the way to go?

You may want to peruse the lengthy threads below that go ad naseum into the ideal 45 case, shoulder and neck dimesions, et al. The 45 vincent short is very similar to the 450 G&A. There also was the 450 Howell. These are all 2.5" long (2.55" for the howell) 404's that will develop 458 lott level loads.

The big question is, does the small shoulder provide a reliable means of headspacing. I was planning on a 45 using the 416 howell reamer, but I was bothered by both the short neck, and especially the abreviated shoulder.

Anyhow, for your proposed conversion, I'd expect there to be some rail work involved, for consistant feeding extraction.

I'd recomend you see if your whitworth was set up for 375 H&H length rounds. If so, the answer is clear, go 458 lott or watts.

Paul,
I already checked that and its not. I'll have to stay with a short cartridge.

Well then, if you've settled on a 2.5" 404 necked up, then its just a matter of what reamer your smith has. I did e-mail Saeed to get some dimensions on the Vincent short to compare it to the 458/416 howell, but then decided to forgoe that project. I do have dimensions for the 450 Howell (not the same as a 458/416 howell), and there are dimensions posted for the 450 G&A.

If you are starting from scratch, ie paying full bill on a reamer, and dies, I think most of the routes will be pretty spendy. You'd likely be $'s ahead selling your 458 Mk X, buying a CZ-550 458 winny, and having it reamed 458 lott/watts. When you factor in bottom metal, reamer, and dies for the various 404 based 450's, you're looking at nearly $1k.

On my M98 based 458 project I elected to go plain jane win mag due to the costs, and issues of the 404 case. That conclusion was based on the advantage of having a 500 Jeffrey in the works, that would fulfill any shortcomings of the win mag, as well as be more then any 45.

If I were somewhat practicle and sensible (which I'm not) I'd simply sell the components I've aquired for the 458 and 500 projects, buy a spanking new 458 win mag CZ 550, and have it reamed and stamped 458 lott. I just have to assume Hornady will have 458 lott dies around the corner for ~$40 retail.

But alas, that's too easy, makes too much sense, and isn't nearly as much fun as learning things the hard way

Paul,
My friend has the 450 G&A Short dies which i can use. I can get it rechamberd, action rail work done and new box and follower for$550.

Well then, let us know how you like your 450 G&A when its finished

Paul,
I'm sorry about calling it the Vincent Short when it's actually the G&A Short.