Thread pitch for gas cylinder?

[CHW2021]

Jimb, please check your messages.

[Richard H Brown Jr]

Unless it's a collectable m-1 carbine, the fact that you blew out the gas piston, might indicate more damage to the gas piston assy that's braised/welded to the barrel. Cracked? The Gas Piston nut was staked on so it shouldn't have come loose. Have you had a *GOOD* carbine gunsmith look? or magnafluxed or other metal inspection tests done to see if the gas piston housing is hosed? A n. o. s. in packing barrel replacement might be a better idea.

RHB

[Tuna]

Not all carbine castle nuts were or are staked. If it was not staked and just shot loose then the damage will be minimal if any at all. But as stated a staked castle nut coming off would do damage to the gas cylinder threads if not damage to the cylinder itself.

[CHW2021]

The carbine is a Universal, it is one of the "clones" using surplus style parts and is interchangeable with military guns. The gas block was drilled so close to the edge of the block that it did crack and allow the nut & piston to blow out. I had the block welded, it is a good job done by a experienced pro; the threads for the piston were not improved by the whole process. I can not justify the cost of a new barrel on this gun (and am out of work) so I am in the position of trying one last thing before shelving the rifle for better times. Yes, I am aware that the gas block could fail again, so be it if it does, the gas escaped into the stock and no one and nothing was harmed. Not a perfect solution to my issue I know, but my world is not a perfect place at this time. Thank you gentlemen for your input, your experience is very helpful.

Charles

[Tuna]

Charles, As to your Universal being compatible with USGI parts. It all depends on your serial number. The only ones that are 100% compatible are the first series which is up to about the 25,000 serial number range. From there on the amount of USGI parts that are useable drops. The later ones have really no compatibility left as Universal made all their own parts by then. The gas cylinder is different then a USGI one. The castle nut is not staked in a Universal and the piston is reversible to turn the rifle into a bolt action. Welding of the gas cylinder does not work very often. The cylinder often cracks again where it is weakened beside the weld as the weld is stronger then the surrounding metal. This happens in USGI carbine barrels as well as Universal carbines. If it does crack again the only way to fix it is to replace the barrel. Hope yours turns out OK.

[CHW2021]

The odds are certainly not in my favor, but it seems to be worth a try. I suppose I am just cheap, but I am having enough money problems to justify a try.
Thanks again.