breechplug torque

[trigrcreep]

Hi I am starting a rifle build.I picked up a .45 gm 13/16 barrel. When I was setting up the breech plug the threads got buggered up :shocked2: It was just about right too.Well Im goin to order another plug but I dont want to tear it up too. Thanks, Bill

 

[galamb]

I don't use a torque wrench so can't give you a "value".

I normally time until the plug really "stops" pretty tight (without exerting any significant force) with about 1/4 to 1/3 of a barrel flat from where I want it to finish up.

I then use "some force", with a box wrench operated 1 handed to get it that last little bit - usually just a couple of "quick" pulls to load the threads.

I read somewhere "if you have to use an 8" long wrench and both hands exerting significant force to get the plug in, it is too tight" (or words to that effect).

You don't want a sloppy plug or one that is not properly timed.

But you don't need to close it up like Fort Knox either. It will stay in there just fine with reasonable force. It's more important that it bottoms to the shoulder - a gap at the back of the barrel/breech plug, while "unsightly" wouldn't necessarily present any safety issues - crushing your threads trying to close that gap is far more dangerous.

 

[hawkeye2]

"When I was setting up the breech plug the threads got buggered up"

The breech plug threads got buggered up? When you damage male threads you usually do a corresponding amount of damage to the female threads it is being screwed into.

 

[M. De Land]

This needs to be right for safeties sake so I would recommend you farm it out to someone who has experience doing the job.
Torque would change with each application and there is no need to tighten until they smoke.
Actually once reasonably tight they need a couple bumps with a hammer on the wrench to seat them.
Shock is what does the trick not raw torque, same as when taking them off.

 

[Pete G]

Most barrels that are breeched by the maker will have a plug that is so tight that removal requires a 12" wrench and some serious hammer work. Personally I think this is a little too tight. I prefer to breach a barrel so that a few taps with the hammer will bring it into final alignment and just a few taps the other direction will break the seal. It is possible to pre stress threads enough to cause a failure when additional stress is applied, like pressure from firing.