Converting a Ruger New Vaquero from a 357 to a 45

[Black Bart Sr]

I have a pair of Ruger New Vaquero Stainless  357's. Is it possible to convert it to a 45?

Will it work by boring out the cylinders and replacing the barrels. 
Note: I was going to change out the barrels anyhow and they are already slicked up. I shoot Classic Cowboy. 

[Arth Ritis]

I would imagine it might be cheaper to slick up a factory pair of 45's but if there is some sentimental value.... I can't really speak with any authority on the subject though.

[Double Barrel, SASS 34765]

If it was me, I’d try to trade them for a pair of 45’s. 

[The Original Lumpy Gritz]

Easier to sell'em and buy .45's.

You convert those, Ruger won't touch them for service.

[Rye Miles #13621]

Yea I agree with the above comments, sell em and get some .45’s. How are you shooting  Classic Cowboy with .357’s.?
 I don’t understand you said you shoot CC. 

Edited August 13 by Rye Miles #13621

[Lawdog]

I have seen conversions from .32 to .38.

 

But that might be too big of a jump.

 

I would have to join the "sell them and get the 45" gang.

[Eyesa Horg]

52 minutes ago, Rye Miles #13621 said:

Yea I agree with the above comments, sell em and get some .45’s. How are you shooting  Classic Cowboy with .357’s.?
 I don’t understand you said you shoot CC. 

Maybe a second set of revolvers.

[Rip Snorter]

Colt, when it was not CZ, did a caliber change on an SAA for me from 44-40 t0 45.  Worked out well.  Might be worth finding out if Ruger will do it, though finding another Ruger in the chosen caliber will be easier & quicker.

[Black Bart Sr]

Rye Miles #13621

 

I have 45 Bisley Vaquero's. The 357's are what I started out with.

I have two sets of the 357's all slicked up from Boomstick with RW Bisley's frames.

I love the RW bisley frames!

[Nimble Fingers SASS# 25439]

15 hours ago, Black Bart Sr said:

I have a pair of Ruger New Vaquero Stainless  357's. Is it possible to convert it to a 45?

Will it work by boring out the cylinders and replacing the barrels. 
Note: I was going to change out the barrels anyhow and they are already slicked up. I shoot Classic Cowboy. 

Not sure but throwing it out as it has worked for me with 3rd gen Colts. Can you buy new model Vaquero cylinders and barrels to replace the .38 caliber ones?  EBay usually has parts might be other sources, even Ruger?  Can’t see how Ruger would still service the gun if it has a Ruger barrel and cylinder in it.45 on the .38 frame as it is the same size frame, yes?  Just a suggestion, but again as others have said sell yours, or trade, and the buy the .45s. 

[Eliphalet R. Moderator]

There have been plenty of conversions the other way, from .45 to .357 by swapping parts and smithing them to spec.  You'll find cylinders and barrels on eBay.  There were barrels for sale in the Classifieds recently.   I was never worried about sending a gun back to Ruger; they'd set everything back to factory specs, and there go all the "go fast" mods.

[H. K. Uriah, SASS #74619]

I can't speak to Rugers, but apparently, once upon a time, converting Colts from one caliber to another was rather common.   I have two .44-40s that have become .32-20s for example.   In both cases, the barrel and cylinder have been replaced by persons unknown in the mists of history.   More interesting is a .32-20 that has become a .22 Hornet via a barrel swap and lined cylinders.

I also have a .38 S&W Bisley they may or may not have been converted from a .44.   If this is a conversion, it's a barrel/cylinder swap, not a bore lining.

I'd say doing the swap is much easier and FAR less expensive that doing a physical change to the existing ones.  (Don't ask me how I know.)   But even easier would be just getting new pistols in the desired caliber.   You can either trade in the old ones to defray some of the cost, or just add the 45's to your collection.   That's what I'd do.

[Catgut Cav]

If you happen to go the, sell them and buy .45s route, please let me know.

I would be interested in the .357s  Although, I'm not sure they'd be in my price range. 

[Billy Boots, # 20282 LTG-Regulator]

11 hours ago, Eyesa Horg said:

Maybe a second set of revolvers.

exactly.

[watab kid]

14 hours ago, Eyesa Horg said:

Maybe a second set of revolvers.

my thought as well , why muck about with a perfectly good brace of revolvers that are still something ruger would service ? just buy a second set of revolvers in 45 - i did the opposite , had 45s and bought 38s , now i have choices 

[Vail Vigilante]

If you find a gunsmith that has the equipment and knowledge to tackle such a project, you will have more tied up in it than if you had gotten two new wheelguns.

Buy two new wheelguns and keep these as your backup pair.

[Captain Bill Burt]

The bolt notches of both calibers are centered directly over the thinnest part of the cylinder wall.  On the .45 that metal has been heat treated to handle the bolt wear.  On a .357 there's no need to do that due to the increased thickness of the cylinder wall.

[watab kid]

interesting point , i was thinking the cylinder might not have the beef for it but hadnt thought about heat treating 

[Captain Bill Burt]

Just an example of AI being stupid. It told me that you couldn’t bore out a Ruger 357 cylinder to .45 because the walls would be to thin. So I asked it what the dimensions of .357 and .45 cylinders were  and it told me they were the same. So I asked it if they were the same then wouldn’t boring out result in the same dimensions., which it agreed was true. It seemed to figure out that its statements were contradictory so it mentioned the notches and heat treatment.

[joachim slim]

Just buy new guns or trade for some. Easy Peazy

[watab kid]

4 hours ago, joachim slim said:

Just buy new guns or trade for some. Easy Peazy

absolutely 

[Rye Miles #13621]

On 8/15/2026 at 6:51 AM, Captain Bill Burt said:

Just an example of AI being stupid. It told me that you couldn’t bore out a Ruger 357 cylinder to .45 because the walls would be to thin. So I asked it what the dimensions of .357 and .45 cylinders were  and it told me they were the same. So I asked it if they were the same then wouldn’t boring out result in the same dimensions., which it agreed was true. It seemed to figure out that its statements were contradictory so it mentioned the notches and heat treatment.

They often correct themselves when you find them in error.

[MBFields]

22 hours ago, joachim slim said:

Just buy new guns or trade for some. Easy Peazy

This. 🤠 You must have good reason for wanting to do this and I respect that. But I would also say" Work smarter not harder".

[Randy Saint Eagle, SASS # 64903]

On 8/13/2026 at 8:02 AM, Rip Snorter said:

Colt, when it was not CZ, did a caliber change on an SAA for me from 44-40 t0 45.  Worked out well.  Might be worth finding out if Ruger will do it, though finding another Ruger in the chosen caliber will be easier & quicker.

If Ruger did it they would remove any slicked up parts and put them back to factory stock condition. 
 

Randy

[watab kid]

the cost will negate doing it as compared to buying new - just do it [or buy used ]