Rossi Circuit Judge Question

[GarandMan94]

Hi everyone,
I was wondering if it was possible to cut the cylinder for moon clips to allow the use of .45ACP in the rifle? If anyone has such a conversion how was it done and by whom?
I would like to buy one as a truck gun, the option of switching between shotgun shells and regular cartridges is appealing. However i would only choose this rifle if it could fire .45ACP, my carry gun is a 1911 so a common ammo type for my truck gun is a positive. I also have lots of .45ACP ammo both factory and hand loads. I don't want to have to buy a new ammo type.

 

[CarJunkieLS1]

Going on a limb here but I would think that anyone or any shop capable of doing moon clip conversions could do it to the cylinder of the circuit judge

 

[Dr T]

It could probably be done, but personally I would not shoot it due to potential headspace problems. The .410 and 45 Colt headspace on the rim.

The key dimension is the rim thickness. The thickness of the rim on the .410 and 45 Colt is 0.060"

The direct comparison to the conversion you are looking at is the 45 Auto Rim. This is a rimmed cartridge which was designed to be used in lieu of the 45 ACP with half moon clips. The rim thickness of the 45 ACP is 0.049" and the rim thickness of the 45 Auto Rim is 0.089", 0.029" more than the 45 Colt and .410. This implies that the thickness of the half moon clip is 0.040.

If the conversion was made, either you would need half moon clips about 0.011" thick or would have to relieve the back of the cylinder 0.029" to accept a standard half moon clip. A half moon clip about a hundredth of an inch thick sounds awfully thin to me. And an extra 0.03" of headspace is a lot more than I have any interest is being around if you are shooting a .410 or 45 LC (that is, if the firing pin could even hit the primer).

A conversion seems like a one way street to go from a gun that will shoot 45 Colt and 410 to one that will only shoot 45 ACP.

And that is all BEFORE you have to deal with the pressure issues. The 45 ACP is rated for far higher pressure than the 45 Colt. The question is, can the Rossi cylinder handle the 45 ACP pressure.

 

[gotboostvr]

It could probably be done, but personally I would not shoot it due to potential headspace problems. The .410 and 45 Colt headspace on the rim.

The key dimension is the rim thickness. The thickness of the rim on the .410 and 45 Colt is 0.060"

The direct comparison to the conversion you are looking at is the 45 Auto Rim. This is a rimmed cartridge which was designed to be used in lieu of the 45 ACP with half moon clips. The rim thickness of the 45 ACP is 0.049" and the rim thickness of the 45 Auto Rim is 0.089", 0.029" more than the 45 Colt and .410. This implies that the thickness of the half moon clip is 0.040.

If the conversion was made, either you would need half moon clips about 0.011" thick or would have to relieve the back of the cylinder 0.029" to accept a standard half moon clip. A half moon clip about a hundredth of an inch thick sounds awfully thin to me. And an extra 0.03" of headspace is a lot more than I have any interest is being around if you are shooting a .410 or 45 LC (that is, if the firing pin could even hit the primer).

A conversion seems like a one way street to go from a gun that will shoot 45 Colt and 410 to one that will only shoot 45 ACP.

It can be done so that all three cartridges work.

You only need to remove material where the moonclip sits, leaving the cylinder untouched on the roughly 1/3rd furthest from the cylinder ratchet. So 45LC/410 rims will sit normally along the outside of the chamber, and the 45acp moonclips will still "sink" into the recess cut for them.

 

[Dr T]

Here is an article about doing such a conversion on a double action revolver.

https://americanhandgunner.com/handguns/revolvers/45-colt-conversion-loading-concepts/

 

[tark]

Sounds unsafe to me. The 45 Colt operates at 14,000 PSI. The 45 ACP at 21,000 PSI. Those are SAAMI figures. This is what happened to a Webley Mk. VII. The .455 Webley cartridge operates at about the same pressures as the Colt. How strong is the cylinder on your Circuit Judge? You would be shooting the equivalent of a proof load every time you pulled the trigger.

 

[js8588]

Sounds unsafe to me. The 45 Colt operates at 14,000 PSI. The 45 ACP at 21,000 PSI. Those are SAAMI figures. This is what happened to a Webley Mk. VII. The .455 Webley cartridge operates at about the same pressures as the Colt. How strong is the cylinder on your Circuit Judge? You would be shooting the equivalent of a proof load every time you pulled the trigger.

People have (stupidly) fired HSM Bear Load 45 colt through the Circuit Judge & survived. It isn't rated for Ruger level 45 Colt but if it will survive it, it can shrug off 45ACP. I still wouldn't do this, but I'm sure you could.

 

[tark]

People have (stupidly) fired HSM Bear Load 45 colt through the Circuit Judge & survived.

People regularly shoot 45 ACPs in shaved cylinder Webley's and get away with it. Doesn't mean it's a good idea. I don't know what 45 Colt proof pressures are, but if they are at 50% higher than normal , that would put them right even with 45 ACP standard pressures. I wouldn't be comfortable proof testing a gun every time I fired it.

 

[js8588]

People regularly shoot 45 ACPs in shaved cylinder Webley's and get away with it. Doesn't mean it's a good idea. I don't know what 45 Colt proof pressures are, but if they are at 50% higher than normal , that would put them right even with 45 ACP standard pressures. I wouldn't be comfortable proof testing a gun every time I fired it.

Modern metallurgy matters. Webleys are C&Rs. Rossis are newly made.

 

[tark]

Modern metallurgy matters. Webleys are C&Rs. Rossis are newly made.

Yes, you have a good point...BUT...they are still a gun designed to operate at 14,000 PSI , not 21,000. The OP did say he handloads 45ACP and he could easily work up a milder, but still effective load.

 

[GarandMan94]

Thank you all for the feedback, I didn’t think about the head spacing issue.
I was going to disregard the case pressure since my hand-loads are really light so i can shoot for longer periods and extend the life of the brass. But after so more thought i would probably need to crank it up so i don't get a squib.
I guess ill have to wait for Ruger to make the PC Carbine in .45ACP or find a good priced Marlin Camp Carbine at a gun show.