Oversized 45 Colt reamer to rechamber 45 acp cylinder?

[singleaction]

I've read that one can't rechamber Ruger BH 45 acp cylinders to 45 Colt, but I don't remember why. I'm guessing that maybe the major diameter of factory 45acp chambers are a little too wide? Well, if this is the case, then why not just order a 45 colt reamer that is just wide enough to clean up over a 45 acp factory chamber? This is probably too expensive to be cost effective, but I think it might work. I used to own a 45 colt BH (made in 1975) that had enormous chambers that severely bulged cases upon firing, and the chamber throats measured .458" to .459". I neck sized fired brass and used unsized .455" diameter Lyman 454190 bullets made from 3:1 ww:lead alloy. Neck sized reloads strongly resembled 44-40 rounds. With 6.0 grains of "old dirty Red Dot" or 6.2 grains of "new-  less dirty, but still dirty Red Dot", I got decent accuracy and 850fps or so. What got me thinking about the rechambering idea, is that my two favorite standard pressure 45 Colt loads use .454" to .455" bullets (unsized RCBS 45-270 SAA and Lyman 454190). Both of these bullets tend to shoot best for me unsized in matching chamber throats. I think it would be useful, and just plain cool, to have a mid frame Ruger 45 Colt with dual 45 Colt cylinders. One with .4525" chamber throats and one with .455" chamber throats. Since the rechambered cylinder would have recessed case heads, telling the two apart would be a no brainer. I don't think a chamber would need to made so oversized as to create a safety issue with standarsdish pressure loads, and with the mid frame cylinder diameter, "Ruger Only" loads are not in the equation anyway. Am I full of beans, or is this a viable idea? Thanks ahead of time for your input. 
Matt

[shorty500]

Actually .45 ACP chambers that are of proper dimension are in the .479/.480 diameter range where the Colt SAAMI spec minimum chamber diameter is .483/.484

[singleaction]

Sept 5, 2016 8:10:42 GMT -5 shorty500 said:

Actually .45 ACP chambers that are of proper dimension are in the .479/.480 diameter range where the Colt SAAMI spec minimum chamber diameter is .483/.484

True. But factory chambers are often oversize. The 45 Colt I mentioned above is a good example. I imagine some 45 acp cylinders are amenable and others are not.

[shorty500]

Not saying there isnt one out there but odds of finding an oversize ACP chamber are extremely slim

[singleaction]

Sept 5, 2016 17:37:18 GMT -5 shorty500 said:

Not saying there isnt one out there but odds of finding an oversize ACP chamber are extremely slim

Given the fact that 45 acp headspaces on the case mouth, you are probably right. I hadn't really considered that til now.

[aciera]

Not sure but 483-484 is not minimum.......480 I think.

[singleaction]

Sept 5, 2016 19:47:10 GMT -5 aciera said:

Not sure but 483-484 is not minimum.......480 I think.

I don't know what SAAMI min and max is, but most cartridge prints I've come across show a case body diameter of .480". I would tend to think that min SAAMI specs would be at least slightly larger than that. Custom revolver builders commonly cut 45 Colt chambers to .480" though.

[shorty500]

SAAMI minimum is either .483 or .484, custom builders cut at .480 same as FA does for the .454 Casull.

[aciera]

John Linebaugh cuts to 480.

[edk]

SAAMI drawing is here

As you can see the cartridge max is 0.480" even though one rarely (if ever) comes across one that size.

It is amazing that Ruger Flat top cylinders are pushing 0.480" given they are a major manufacturer.

[Deleted]

The fundamental question was never answered. Can a typical new model Blackhawk 45 acp cylinder be reamed to 45 colt? As far as I can tell is if the diameter and length are same, then it should work? But I've thought wrong before.

[tdbarton]

My .002 that doesn’t in any way answer the question: From my limited experience, .45 acp cylinders are often sought after and hard to find. Sell the ACP cylinder to finance a .45 Colt cylinder.

[aciera]

Can’t see why not......if you can indicate worth a darn.

[aciera]

Sept 11, 2021 13:34:56 GMT -5 tdbarton said:

My .002 that doesn’t in any way answer the question: From my limited experience, .45 acp cylinders are often sought after and hard to find. Sell the ACP cylinder to finance a .45 Colt cylinder.

Point well taken

[Deleted]

That's good idea. I just bought a cylinder that the guy said was 44 mag but it's 45 acp. I was worried because it's fluted and tough to find blue fluted 44 mag cylinder. Thanks.