1919 A4 Forums banner
1 - 3 of 3 Posts

·
Registered
Joined
·
2,100 Posts
Discussion Starter · #1 ·
This ZB26 barrel, formerly in 7.92, has been sleeved for 7.62X39 by the Chinese and the gas port on the gas block has been threaded for a screw on port. Possibly a repair to a damaged port, but, in my opinion, the effort to thread the port and make the screw-on plug far outweighs the effort to just replace the gas block. The screw-on port is longer than the standard port. The orifice in the screw-on port is smaller than the usual port orifice in a 7.92 barrel. The gas channel in the 7.92 barrels is quite large from the oval port in the bottom of the barrel to the orifice in the face of the gas block port. The Chinese ZB26 that I shoot in 7.62X39 functions close to the edge of failure-to-fire in FA and can short cycle at times regardless of ammo. I suspect the screw-on port was an attempt to reduce the port size to increase gas pressure for the same volume, leaving the barrel port and channel to the port the same size.
I have many 7.62x39 barrels, most with chambers and bores in very good to excellent condition, but none will reliably run the gun in full auto in that caliber. The barrel with the screw-on port actually does function the action far better in FA than the other barrels.
Having handled many 7.62X39 ZB barrels, this is the first with a screw-on port I have handled.
Anyone else run into this type of barrel mod?

Pic. #1: screw-on port to left and standard port on right.
Pic. #2: port unscrewed

Screw Metal Pipe Auto part Tool accessory Auto part Cylinder Metal Pipe
 

·
Registered
Joined
·
288 Posts
I'll have to dig out mine and take a look. I have 5 of the 7.62X39 Chinese barrels but i have never gotten around to try to run the gun with them. I did get a chance to shoot a post sample Chinese made ZB26 in the 7.62X39 and it worked fine.
 

·
Registered
Joined
·
35 Posts
Bob: Is it my imagination or the angle I am looking at the photo's of the two gas ports in that the one with the sleeve seems to be a bit further back on the barrel.
It appears to be about 1/3 of a ring further back towards the breech. It is also centre punched as well.
 
1 - 3 of 3 Posts
Top