Just how tight should a breechplug be?

[Pete G.]

I just finished breaching a barrel then cleaned everything and put a spot of grease on the threads for the final seating. This time it ran in much smoother of course, but I was able to turn it all the way in with a good hard pull on the wrench. Tried to unscrew it, but it was tight enough to require q pretty good whack with the hammer to break it loose. I'm thinking it is probably OK, but every barrel that I ever got from a barrel maker required quite a bit of effort to unbreach. It seems to me that you really wouldn't want to put an awful lot of preload on a stressed part, but the barrels I've gotten from Colerain and Rice were extremely tight. Am I good to go or should I work on turning this one in another round and get it tighter?

[Randy Hedden]

Your breech plug should be plenty tight. Of course when you buy a barrel that is already breeched from a barrel maker You wil have to return the breech plug to the position that the witness mark lines up. If you don't the top flat of the barrel and the top of the tang will not be even with each other.

Randy Hedden

www.harddogrifles.com

[T*O*F]

Tried to unscrew it, but it was tight enough to require q pretty good whack with the hammer to break it loose. I'm thinking it is probably OK, but every barrel that I ever got from a barrel maker required quite a bit of effort to unbreach.

It is not the tightness of the threads which make it hard to remove.  When you tighten the plug that last little bit, the top and bottom face of the breechplug is making an interference fit against the back of the barrel.  Since there is no lube on any of those faces, they are essentially galling themselves together.  When you go to remove the plug, that first whack breaks the friction seal between the plug and the barrel.

I've never tried it, but I bet if you greased all those areas and re-installed the plug, it would easily turn past the witness mark.

[don getz]

Pete.....I,ve breeched a lot of barrels, this one sounds good to me............Don

[northmn]

Tight isn't as critical as fit.  You get two friction points with a well fit plug.  One where the plug tightens agains the barrel and the other where it tightens against the bottom of the breech.  Most plugs are breeched square, ie 3/4" plug by 3/4" deep, which gives plenty of safety.  Tightness in thread fit is also somewhat important as that can vary also.  Were you to remove the plug a great deal it would loosen up such that the witness marks would be advisible.  I remember a laughable example I read in the American Rifleman where a "expert" evaluated a traditional ML and commented that his primary fault with the gun was that the plug did not come off handily for easy cleaning after shooting.

DP

[Dphariss]

I just finished breaching a barrel then cleaned everything and put a spot of grease on the threads for the final seating. This time it ran in much smoother of course, but I was able to turn it all the way in with a good hard pull on the wrench. Tried to unscrew it, but it was tight enough to require q pretty good whack with the hammer to break it loose. I'm thinking it is probably OK, but every barrel that I ever got from a barrel maker required quite a bit of effort to unbreach. It seems to me that you really wouldn't want to put an awful lot of preload on a stressed part, but the barrels I've gotten from Colerain and Rice were extremely tight. Am I good to go or should I work on turning this one in another round and get it tighter?

Depends. Its not like installing a barrel on a 300 mag bolt gun.
It really needs no more than to be nice and snug with a 10-12" wrench. Maybe 30 ft lbs for you torque wrench types.  Making it really tight accomplishes little since the "clearance" of most modern taps provide plently of room for fouling.

Seating it against a shoulder internally does not increase the torque requirement. This will generally prevent it going past the index if reinstalled.
I use STP to lube everything and when it gets close I work it back and forth a few times and it will turn in a little farther each time. Doing this gives a better "crush" prevents it from going too far if removed and reinstalled.

Dan