re-bore/chamber blackhawk cyl.

[santabob]

i have a .44 magnum cyl. well used. and wish to convert it to .45 acp. to use in my .45 colt black hawk. it does fit very well and indexes as it should.
anyone done this with a drill press ? have to locate a fixture if possible. would pay to use reamers ,etc.
if it is not a good idea i will just sell the cyl.

 

[Chuck 100 yd]

For the best outcome and pleasure ,keep on looking for an ACP cylinder. They show up on line fairly often it seems or place a WTB add here. I bought a nice SS one for what the reamer rental would cost.

Now,if you like to tinker,go for it. You can rent the reamers,it will take two,one for the chambers and one for the throats unless you can find one that will cut both at the same time. Can the drill press idea, you can do it better by hand.

 

[Hondo44]

I agree with Chuck on both counts:

Much simpler to get an ACP cyl. There's no issues about it timing right, but the overall length must be right or a liitle long so the gas ring can be simply fitted to length of your cyl window frame.

There's so little material to remove, hand reaming will be extremely easy and may be safer. Always the potential for power tools to screw it up when one doesn't often do it. The chamber shoulders for the case mouth to headspace on must be correct depth. Rimless cartridge chamber shoulder placement is critical. Not like rimmed cases that headspace on the chamber mouth. You might find a reamer you can borrow from a member just for two way postage. You only need one reamer, but with a pilot to fit the existing .429" throats. Or one with a replaceable pilot and make a .429" pilot for it.

 

[Redington Slim]

send it to John Gallagher.

 

[DougGuy]

The .44 cylinder is already too big in diameter where the headspace ledge would need to be for .45 ACP. It needs to be .4525" diameter at a point .900" from the breech face and the .44 magnum chamber/charge hole diameter is approximately .4585" at that distance from the breech face.

 

[Hondo44]

The .44 cylinder is already too big in diameter where the headspace ledge would need to be for .45 ACP. It needs to be .4525" diameter at a point .900" from the breech face and the .44 magnum chamber/charge hole diameter is approximately .4585" at that distance from the breech face.

I believe you meant the 44 cylinder chambers, but they are not too large in diameter to cut in a proper 45 ACP shoulder. The ACP case mouth is .470" and the .45 chamber reamer will open it to .476" at the .900" chamber depth at the point of the shoulder which is correct to properly headspace the 45 case mouth. It's true that immediately ahead of the shoulder the chamber will be .4585" but it quickly transitions to the .452" reamed size for a proper length and diameter throat for the 45 ACP.