Cooey-Carcano 7.62x39 Project

[tiriaq]

The rifle known as the Cooey-Carcano was marketed in the 1930s by Eatons. It was a sporterized Carcano service rifle with cut down stock with added pistol grip, double set triggers and a barrel retrofitted in 6.5x54 Mannlicher-Schoenauer. The original barrel was cut off and the stump bored out and threaded to accept a shoulderless replacement barrel. Once turned in and headspaced, the barrel was prevented from turning by a setscrew. This setscrew is about as useful as the ones installed on Chinese M305 M-14 clones.
Some time back, I altered one of these rifles to 7.62x39, using a No. 4 .303 barrel. This was cut off at the breech, turned and threaded to fit the original barrel stump, and chambered. Worked fine. The 7.62 rounds fit the chargers, and fed OK.
Recently I acquired a ratty C-C to make up one of these conversions for myself. I plan on taking photos as I go, to create a tutorial for anyone interested in such a project.



The double set triggers are missing the adjustment screw.



The sear housing has had a kicker added to function with the double sets.



The set screw has been removed.



I'll add more posts and photos as the project proceeds.

 

[Snider shooter]

This could be interesting as I happen to have 3 Cooey carcano’s. Multiple #1and#4 Lee Enfield barrels. A couple have been shortened. Show us the goods.

 

[MilitaryCollectorMark]

Very interesting!

 

[billdick]

I modernized a couple of these way back when. I cut the bolt handle off and welded the channel closed on the top of the receiver, notched the right side of the receiver at the back and welded the handle back on. Once all the modifications were done I drilled and tapped up top and mounted a scope. A guy I sold one to rebarreled to 6mmppc if I remember right.

 

[RRHK]

I've just completed a similar project, used a p14 barrel. I am however having a hard time getting it to feed properly. I believe I need to fill in the area in front of the charger clip and make a new feed ramp. The original feed ramp causes the shell to kick straight up past the top of the chamber. Do you have any advice for this

 

[tiriaq]

The last one I did fed without adding a feedblock. I wonder if your clip is OK?

 

[OkayShooter]

Sweet.

 

[Andy]

Thanks for posting. Watching with interest.

 

[tiriaq]

Made some progress today.

Set the barreled receiver up for disassembly.
Barrel clamped in barrel vise.



Stump of original barrel clamped using receiver wrench made for flat sided receivers (Win 94, etc.).



The barrel was in TIGHT. Turned it out with an 18" cheater; 3 feet would have been better. First 4 or 5 turns were tight.




You can see the little divot that the setscrew engages.

Now, some dimensions:

Barrel diameter where it is covered by the stump: 0.814".
Thread diameter: 0.808"
Thread pitch 20TPI. Measured with thread gauge.
Thread length: 1.05.
Barrel covered by stump: Total of 2.40"

The threads are very, very close to 20TPI. Maybe 1.25mm metric? I don't have a metric thread gage, and my lathe won't cut metric. 20TPI will work.

The next steps will be to turn the breech end of the barrel to .814" - or a bit less. No shoulder, just turn the breech end to that diameter. Adjust the length at the breech to get rid of as much of the residual chamber as needed. Thread the breech to fit the stump. Measure headspace gauge protrusion from the original 6.5x54 barrel. Ream the 7.62x39 chamber until the same gauge protrusion is achieved. Turn in the barrel, check headspace - adjust as needed. Drill set screw divot? Wouldn't do any harm.

Decide what I am going to do for sights.

 

[anglia2]

I'm building a similiar project . Where did you get your reamer from ?

 

[jamesharrison]

When we were doing a similar project with Lee Enfield receivers using cut-off Lee Enfield barrels to make the barrel stubs, we simply cut 13/16x20tpi (UNEF) as the thread & the C-C barrels spun right in. A simple touch with a 6.5x53R reamer [there were only 6-7 wee chips of metal removed to re-chamber the 6.5x54MS barrels & voila, instant .256 Mannlicher rifles were created. The only problem was the short, barky 20" C-C barrels. I am, however, about to create another as I recently located an almost-new 29" 6.5x53R barrel.

Don't overthink it!

;-)

 

[tiriaq]

Bought it years ago, probably from Brownells. I believe it is a Clymer.

 

[tiriaq]

I have been considering options for mounting optics. A conventional scope must be offset to allow the chargers to be loaded. In my cache of odds and ends, I found this Williams side mount. It is intended for a flat sided receiver, and mounts the scope left of center. I could easily machine a shim radiused to fit the left sidewall of the receiver and flat to fit against the base. Three holes would be drilled and tapped. The receiver in the area is about 1.24" in diameter. Take a piece of tube, bore it to that ID, then mill a flat, reducing the wall thickness to a minimum. Cutaway the unneeded portion of the tube, leaving a small appropriately shaped shim, flat on one side, radiused on the other.




A longer eye relief scope mounted on a base attached to the barrel is another option, of course. An offset scope is a bit odd to use.

 

[Andy]

When we were doing a similar project with Lee Enfield receivers using cut-off Lee Enfield barrels to make the barrel stubs, we simply cut 13/16x20tpi (UNEF) as the thread & the C-C barrels spun right in. A simple touch with a 6.5x53R reamer [there were only 6-7 wee chips of metal removed to re-chamber the 6.5x54MS barrels & voila, instant .256 Mannlicher rifles were created. The only problem was the short, barky 20" C-C barrels. I am, however, about to create another as I recently located an almost-new 29" 6.5x53R barrel.

Don't overthink it!

;-)

I think that you could do this without a reamer, as the front portion of the 303 Brit is quite close to that of the 7.62X39. Establish headspace with a F/L sized 7.62X39 in the chamber, and upon first firing, it's fireformed in an "improved" fashion. Neck size for a while, and then when it will no longer chamber touch the brass up with a 7.62X39 die.

 

[tiriaq]

I have heard of .303 barrels being repurposed for 7.62x39 without the use of a reamer. Last one I did used a No. 4 barrel; I did use a reamer to finalize the chamber - because I had the reamer on hand. Didn't try to do the job without the reamer. I did notice how little metal was removed. I am sure that with careful measurement a perfectly usable 7.62 chamber could be realized without a reamer, simply by being careful when shortening the chamber from the breech end.

 

[Snider shooter]

I have heard of .303 barrels being repurposed for 7.62x39 without the use of a reamer. Last one I did used a No. 4 barrel; I did use a reamer to finalize the chamber - because I had the reamer on hand. Didn't try to do the job without the reamer. I did notice how little metal was removed. I am sure that with careful measurement a perfectly usable 7.62 chamber could be realized without a reamer, simply by being careful when shortening the chamber from the breech end.

So a LE barrel rechambered , set back and put back on a LE action would be an interesting option. Extraction and feeding would have to be worked out. Lee Enfield in 7.62x39.

 

[tiriaq]

7.62x39 Lee Enfield conversions have been done. A Lee Enfield barrel doesn't need much rechambering. The front end of the .303 chamber is just about a 7.62 chamber to start with. Set the barrel back just far enough to get rid of the excess .303 chamber. A Lee Enfield barrel can be breeched against the inner receiver collar if an external shoulder doesn't work.
In Australia, 7.62 and 5.56 conversions have been successful. A repeater is a bit complicated. Because of the smaller, rimless case head, a recessed bolt face might be required. Ejection will have to be dealt with. Conversions in the US have used single stack AK magazines. I have heard of Ruger Mini-30 magazines being adapted. Could a 7.62 AR type magazine be used?
If a single shot plinker is all that is desired, only barrel work is required.

 

[OkayShooter]

So a LE barrel rechambered , set back and put back on a LE action would be an interesting option. Extraction and feeding would have to be worked out. Lee Enfield in 7.62x39.

Making magazine guides for Lee's are easy. Magazine you would want something narrow. Extracting be easy, ejection might be a little difficult as #### and I noticed that the plunger style ejector in a Lee doesn't work too well, the bolt head isn't long enough spring to get really that good rebound to flick it out. I seen someone use a flip up finger ejector but that was for a 9mm.

 

[tiriaq]

At weaponsguild.com, a chap has done LE conversions, and has made trigger guard/magazine housing units from sandwiched aluminum plates. Very neat, tidy work.

 

[tiriaq]

I went through my rack of odds 'n' ends of barrels and found a R700 take-off sporter in .30-06. Measurements indicate that with the .30-06 chamber removed up to the shoulder, there is enough barrel diameter left to duplicate the C-C barrel shank and allow the 7.62x39 chamber to be cut.
Tried my reamer in the muzzle end of the barrel, and the reamer pilot just fits smoothly.
I'll cut a couple of inches off the chamber end, face it, then set it up with the bore on the tail center. Turn to .814", the cylindrical portion merging with the factory taper. Thread 20tpi for 1.05" until the barrel threads into the receiver bushing. Set up for chambering and ream until the appropriate gauge protrusion is obtained. Screw the barrel in and confirm headspace.