I just aquired a Ruger #1 Tropical in .458 Winchester. I was thinking of converting it to another chambering but can't decide which. I still haven't gotten around to having my Pedersoli double converted to .450 #2 Nitro but it will happen soon. Should I convert the #1 to the same round as the Pedersoli or go with something different? I do love the old British Nitro rounds but a .458 Lott might be interesting. What do you guys think? Thanks for the input.

What am I missing on this? You already have a .458 Winchester! This is not a pop gun by any means. Why not just go out and use it as is?

I already have another .458 Winchester. I just bought this gun because I got a great deal from a friend. I thought I would convert it to have something different.

I would turn it into a 460 Weatherby if it were my No. 1 but any of the Nitro Express cartridges should be great. I would stay away from the Lott because it is too common. Good luck.

Goint to another caliber is pretty easy in No. 1. New ejectors are really cheap parts and available in a couple of days from Ruger. I keep a set of all sizes as spares in case I do a conversion. All you do is rechamber and swap the ejector. No fooling around as with most singles.

Mingo-Are you my straight man.If you say he needs an uncommon cartridge, you know the one with the with THE big power he needs to rechamber to....
(458 HE)...

I certainly can understand why you would want another cartridge than the 458 win. I guess the first issue is how much money you want to spend on the conversion. I would certainly recommend keeping the factory barrel, both for looks and cost. Ruger's factory barrels are very good.
The cheapest conversion (already mentioned) would be just lengthen the chamber to the 458 Lott. This is a decent cartridge, but certainly not a "classic" by any means.
In the Ruger, I would recommend a Nitro Express cartridge. Sure, the belted and big rimless cartridges may work just fine, but the big rimmed cartridges just "seem right" for the #1.
One option is the 450 3 1/4" Nitro Express. This has about the same ballistics as all the other NE cartridges (400-500 grain bullet at 2150). However, in the Ruger #1, when loaded to 458 win. mag. pressures, this cartridge will easily approach 2400 fps. Bowen Classic arms does this conversion, and they charge $450. This involves rechambering, recutting the extractor, and minor alteration to the loading chute.
They also rechamber the 458 #1's to the .500/.450 3 1/4" NE cartridge. This is the 500 3 1/4" case necked down. This is a larger case than the 450 3 1/4, so it runs on a little bit lower pressures. There isn't really an advantage to this option for the #1. The cost is also higher because it is a larger case, more reworking of the action is necessary. Bowen charges $750 for this.
Or, you could have the whole barrel rebored to a larger caliber, such as the 470 Nitro Express. Some older Ruger #1's will even accept reboring to 500 NE. However, the more recent Ruger's have the quarter rib screw holes drilled too deep into the barrel. The 500 NE's can usually only be converted from a Ruger #1 with a serial # prefix of 130. The 470 NE conversion costs $895.
Once you decide on a cartridge, there are options you can add that run the price up even higher. Bowen's recessed safety is $495, but it does guarantee ejection of the fired cases. Then, you could add a new recoil pad, mercury reducers in the buttstock, engraving, french gray finish, color case hardening, and the list goes on.
I guess the first thing to decide is how much you want to spend, and go from there. I would recommend either the 450 3 1/4" NE rechambering or the 470 NE reboring. The 470 conversion takes about a year to get back, because the barrel has to be sent out.
Whatever you do, I would get rid of the factory slab of Goodyear tire that is on the stock and replace it with a 1" Pachmayr Decelerator pad or a 1" Kick-Eeze pad.
I had Bowen do a 470 conversion for me in 2002. I just got it back in December, and have not yet been to the range to shoot it. It turned out great and they did a super job on it. If you want further information, drop me an Email.

Homebrew, some one you mite talk to on our coast is Bill's Accuracy he is Maryland,he does alot of work on the No-1's
www.billsaccuracy.com

Homebrew-Mingo is right about my cartridge being
uncommon, but it is a great one for single shots.
"Uncommonly Great"
In the thread below entitled "458 Hubel Express,
getting run of brass made", are pictures of it.
You would only have to ream, just like doing the Lott.Same extractor would work also.If you are reloading my design will outlast weatherby brass by 7-10 times.Perhaps if you want to do a rechamber right away do the Lott, and then later when brass is done, do our big one.Ed.

How about a 500 3" NE,very cool on a #1.

Go for Broke- The .600 Overkill on a Ruger Number 1 was where it all started! The details are all worked out and the dimensions, brass and tooling are available. Think 900 gr bullets at 2500fps! Now that's a single shot! If your gonna upgrade from a .458win, go all the way!!-Rob

I'm thinking .450 Nitro Express but something inside me says re-barrel to .500 Nitro. Any thoughts?

The falling block #1 screems NE, you just have to have a rimmed case in a single shot, that's all there is to it.

If you're going to do the peddersoli double, then I'd definately have the #1 chambered in the same round.

Then again, if you have the funds for a new barrel, 500 NE would be very nice.

So long as you make it into a NE, you can't loose, 450, 470, 500, all good choices