Cooey-Carcano Conversion to 7.62x39

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tiriaq

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Here is the barreled action from a C-C to be converted to 7.62x39. The replacement barrel is a brand new Yugoslav SKS barrel. The diameter of the C-C barrel just in front of the rear sight is .819" (also the diameter of the threads); the diameter of the SKS barrel just in front of the shoulder is .856". The plan is to turn the breech of the SKS barrel to .819 and thread it to fit the barrel stump bushing. No chamber reaming should be necessary - screw the barrel in until headspace is correct. The set screw that locks the C-C barrel from turning is shown in the second photo. The double set triggers work, but the adjustment screw appears to be broken off. That will have to be removed and a replacement installed.
First steps will be to remove the lock screw, then disassemble the barrel from the barrel stump, and confirm the dimensions of the C-C barrel shank.
The shank of the SKS barrel will be then machined.

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Incidentally, the SKS barrel shank is about .976" (25mm) in diameter. Threads are metric, of course, about 17t.p.i. Without using a sleeve or bushing, this somewhat limits its adaptability to other rifles.
 
It’s a great plan for making use of surplus new barrels and old solid actions that could use a resurrection. Mount some current sights that suit the shooter and it would be an excellent and handy woods gun.
 
Removed the setscrew. It was decorative only - didn't engage the very shallow threads. Set the barrel up in my barrel vise, and inserted my internal receiver wrench. The receiver with barrel shank bushing turned off the barrel. The fit was firm - not galling tight, but firm. Had to use the handles on the wrench until the barrel was half way out.
In my first post I indicated that the C-C 6.5 barrel had a diameter of .819" - that was with a Canadian Tire digital caliper. With the barrel out, I remeasured the shank and thread diameter with a Mitutoyo digital caliper and a Moore & Wright micrometer. Mitutoyo said .805", micrometer .806".
Always be careful when measuring! The CT measurement was repeatable - but obviously not accurate. I'll have to check this caliper against my gauge blocks, find out what is wrong, see if it is worth keeping.
Checked the threads - 20tpi with a Starrett thread gauge. The gauge was a good fit. This is the pitch I have observed before.
Set the SKS barrel up in the lathe and started turning down the shank. In the photo, it is at .852" - a ways to go yet. Shop was getting hot, so I stopped for the afternoon. Probably continue in the a.m. when it is cooler.
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No gas port. I expect it would have been drilled after the barrel was installed.
These barrels are threaded at both ends, chambered and contoured for the various parts tht are fitted to the barrel.
 
tiriaq said:
No gas port. I expect it would have been drilled after the barrel was installed.
These barrels are threaded at both ends, chambered and contoured for the various parts tht are fitted to the barrel.
Click to expand...
Cool wasn't sure. Be a cool little project. Good price on the barrel.
 
tiriaq said:
No gas port. I expect it would have been drilled after the barrel was installed.
These barrels are threaded at both ends, chambered and contoured for the various parts tht are fitted to the barrel.
Click to expand...
Are the press fit sks barrels smaller/larger tenon?
 
I do not know. Maybe one of these Yugo barrels could be retrofitted to a press fit SKS receiver. Diameter on the threads is about .980" which I expect would be larger than the shank of press fit barrel. Very little experience with press fit barrels. I do know it takes some equipment to remove and install a press fit barrel.
 
Awesome, I am doing this exact project currently. The one I bought with double triggers the set trigger doesn’t work, so I need to figure that out on top of the other work.

Looks good though!
 
The set trigger unit can be removed to make it easier to work on. Did that with this one. Remove the two springs. There is a retaining screw at the front of the unit. Once it is removed, the unit can be tapped out of its seat in the guard. Tap out the pins and the front and rear triggers along with the little catch piece can be removed. Probably need a good cleaning. The catch piece pivots on the front trigger pin. A 2-56 screw can be used for trigger adjustment, if the original is missing.

Set the headspace yesterday, with the bolt just starting to turn to lock on a CIP spec No Go gauge. Will be test firing it at the range this evening.
 
Test fired last night. Headspace was fine. But the bolt would rotate until the point where primary extraction would start, and then require a hard bump with the heel of the hand to rotate the bolt fully. Once rotated, cases extracted freely. Removed the barrel just now, inspected the chamber. Reamer marks. I'm going to polish the chamber and hope this solves the problem.
 
Will the magazine be modified to feed or will it be a single shot? I converted a husqvarna m96 from 30-06 to 7.62x39 and the magazine conversion and extractor were the most time consuming part to make work. I have seen some people do Lee enfield conversions and use a cz527 magazine riveted inside the original magazine
 
7.62x39 fits the bolt face and extractor, as well as the Carcano chargers. Without chargers, it is a single shot in any caliber.
 
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