Blackhawk cylinder conversion

[Grim Reaper]

Hi everyone and Merry Christmas!!!
I have a 357 mag cylinder and I would like to have it converted to 44-40.
My questions are:
1. Is this physically possible?
2. Is this safe?
3. Can anyone recommend anyone that can do it?
Thanks to all that reply.

 

[COR]

Andy Horvath used to do caliber conversion for around $600 complete gun. I think Hamilton Bowen quoted me about $125 for just a cylinder a couple of years ago. If a 45 Colt fits a 44/40 should...

 

[BlkHawk73]

Clements, Gallagher, Bowen, Hovarth...

If it's gonna get done, have it done correctly buy someone that KNOWS what they're doing.

 

[Driftwood Johnson]

If a 45 Colt fits a 44/40 should...

Not necessarily so. 44-40 has a wider rim than 45 Colt. .512 for 45 Colt, .520 for 44-40. This is the reason that Ruger will not chamber the New Vaquero for 44-40. Statistically they cannot guarantee that all ammo meeting 44-40 SAAMI spec will fit into the New Vaquero chambers without over lapping rims. However with the larger cylinder of the regular Blackhawk, there should be enough space for the larger rims.

As far as pressure is concerned, keep your loads to SAAMI spec for 44-40 and you will have no problems.

You will of course need a barrel. The old 19th Century spec for 44-40 barrel groove diameter was .427. Ruger used their standard .429 44 Mag barrels when they made 44 Mag/44-40 convertible guns.

 

[Lee Martin]

The rim being too large to fit??? Colt chambered SAAs in 44-40 for years. It'll work just fine.

 

[5of7]

Wouldn't there be a length problem? I thought the larger calibers were longer than smaller calibers.

I am assuming here that he want's to re-chamber a .357 cylinder to 44/40 and then use it in a 44 Mg. as a combo gun.

 

[Hashknife Hartley]

You didn't say which type 357 cylinder, but as Ruger's already done it with the large frame NM's, should not be a problem. If you're talking a New Vaquero or Old Model 357, it should still work if as Driftwood says, you watch what brass you're using. I did my OM 357's converted to 44 Special, and here's a couple pics of the outcome.
From the rachet end:

From the business end with 200 gr bullets, 240's wouldn't fit:

I use Windchester brass as the Remington is two thick in the throat area and won't chamber. They shoot great, and with a full load of KIK2F it feels like a true magnum load. Bob James, The Arizona Thumber, in Phoenix, Az, did these for me, plus one for my Flattop 44.
HH

 

[CraigC]

It depends. If we're talking about converting a large frame .357 Blackhawk to .44-40, it should work lickety splickety. If we're talking about converting a mid-frame .357 to .44-40, then it 'should' work fine. However, if we're talking about fitting a cylinder to an existing .44Mag it won't, because the .357 cylinders are shorter. You would have to procure a .41Mag cylinder to have fitted and rechambered.

 

[Driftwood Johnson]

The rim being too large to fit??? Colt chambered SAAs in 44-40 for years. It'll work just fine.

Yes, but a Colt cylinder and a New Vaquero cylinder are not quite the same diameter. In addition, the ratchet teeth on a Colt cylinder are of a different design than on a Ruger. There is more clearance around the teeth on the Colt than on a Ruger. By the way, that photo of the teeth with the 44-40 ammo in position is not typical of the OEM Ruger cylinder design. Those teeth have been relieved to create more clearance. Out of the box, the teeth on the Ruger have less clearance.

Here is a photo of an 'original model' Vaquero cylinder in the center flanked by a 2nd Gen Colt cylinder on the right and an Uberti cylinder on the left. You can plainly see that there is more clearance near the teeth with both the other cylinders than the Ruger cylinder.

As I said before, when the New Vaquero first came out Ruger did the numbers and decided that with the nominal maximum SAAMI spec rim of the 44-40 they could not guarantee that all SAAMI spec 44-40 ammo would chamber. Yes, some independent gunsmiths have been able to ream out the chambers for 44-40, but they are relying on the fact that most 44-40 brass made today does not quite go to the SAAMI max rim diameter. If it did, there would be interference. They also rely on the fact that there is the tiniest bit of slop in the chambers, so that gives a little bit of added grace. But as a manufacturer, Ruger has to guarantee that all SAAMI spec ammo will chamber without a problem, and they could not do that.

I have this information direct from a line engineer who was working for Ruger at the time the New Vaquero came out. But, with the Blackhawk cylinder, or an 'original model' Vaquero cylinder it would not be a problem.

P.S. I had to look twice before I realized that is a 'colterized' three screw Blackhawk. Nice!

 

[5of7]

If rim clearance is the problem, then why wouldn't the reamer be ground up in such a way as to create the clearance for the rims by just removing a little corner off the ratchet just as the proper depth was reached?

If such reamers are not available, they should be.