Breech Inspection

[tx50cal]

Would anyone on here be interested in looking at an old barrel I have and see if the breech area could be repaired?My dad used to own the rifle and removed the plug everytime he cleaned it. It seems a little loose to me, like the threads are worn.

 

[Rifleman1776]

His practice is strongly ill advised.
You are wise in seeking expert input on this.
I'm not the one to help you but feel sure someone with proper knowledge will step up.
BTW: hotoSmile:

 

[50cal.cliff]

Would anyone on here be interested in looking at an old barrel I have and see if the breech area could be repaired?My dad used to own the rifle and removed the plug everytime he cleaned it. It seems a little loose to me, like the threads are worn.

I am not your expert you are looking for but please explain this part of your statement!

Quote: It seems a little loose to me, like the threads are worn.

Are you able to move it when it is in the barrel?

Have you removed it and that is why you feel it is loose?

Pics would make it a whole lot easier for comments on this one! hotoSmile:

 

[tx50cal]

When I put a wrench on it and get a good torque that I like the plug is about 1/2 a flat too far.

 

[Birddog6]

If the threads are engaging well, you will have to clock the breechplug/barrel 7 flats & refit it. If the threads do not engage well, have it rebreeched with a new breechplug. May possibly be able to go 1 size larger ? & get full thread engagement, if need be.

Keith Lisle

 

[M. De Land]

I'd be worried about internal shoulder fit of the breech plug face personally. If it was tight against it originally it should not turn past index on the flats. MD

 

[Zonie]

That is the most common problem with a sidelock that's had the breech removed too many times.

Threads rarely wear out from being screwed together but the face of the breech plug gets scored every time it is retightened against the shoulder at the breech of the bore. The shoulder wears from this too.

With a 5/8-18UNF thread, the breech plug advances .056 per revolution as it screws in.

If the breech plug face and the mating surface in the breech wears only .005 (five thousandths of an inch) the breech plug will have to rotate almost 1/10 of a revolution more than it did with the unworn faces to tighten up again.

This is the reason builders tell people not to remove the breech plug except as a last ditch effort to fix a problem.

 

[tx50cal]

I have thought about using a file and very slowly removing material from the back of the barrel until the plug is snug about half a flat too soon. Then I should be able to tighten it up correctly. I will use the black to make sure that the plug is bottoming out on the shoulder in the barrel.

 

[jdkerstetter]

Unless I'm missing something, I know you're talking about your Dad's old gun, but that's all. What are we dealing with here? Modern, antique, heirloom, what? Flintlock, percusion? Hooked patent breech or what? :idunno:

Don't file the back of the barrel yet!!! In fact don't do anything!

Filing the any off of the back of the barrel will require the barrel being set back and the nipple or vent with it. Or the barrel will have to be shimmed forward with something which means the tang has to move forward in its mortise...hard to do if it's flared and regarless it would mess up the tang bolt alignment.

Again, we don't know what you have here so difinitive advice can't be given as to what the appropriate fix is. Enjoy, J.D.

 

[tx50cal]

It is a Armsport percussion. 50 cal hawkin style cron around 1975. Like stated its like the plug screws in too far. Just for kick I made a brass "washer" .017" thick and it lined it up about right. The problem with this is that it increased the gap between the plug and the barrel inside. This wouldnt be a good fix to use it regularly.

 

[54ball]

This wouldnt be a good fix to use it regularly.

It wouldn't be a good fix to use it at all.

 

[jdkerstetter]

I believe Arsport's Hawkens were made by Investarms, the makers of Lyman and many other Italian import guns over the years. A quick picture of the breech arangement or the various proof marks would confirm this.

Since we can't determine whether or not it's the barrel or the breech that's the problem you might be better served by replacing the barrel/breech assembly.

Investarms single wedge barrels turn up all the time. A quick search of e-bay for cabelas barrel turned up 3 available for less than $200.

Getting a competent 'smith to fix your problem will likely run much more than that, especially considering the replacement cost of Investarms parts.

Just trying to give you some options and some things to think about. Good Luck and Enjoy, J.D.

 

[tx50cal]

This ones made in spain. I tried my Investarm barrel and its a little wider. It looks like I could fit one though.

 

[jdkerstetter]

Since it's Spanish, more than likely you are going to need to and should replace the assembly, I.M.H.O.

The way many of those barrels were set up it's as if there was never an intention of having their plugs removed once, let alone repeatedly.

Enjoy, J.D.

 

[54ball]

There are two companies, ARMI Sport, makers of the German designed Kentuckian, Pattern 1853 Enfields and probably some other type rifles. My ARMI Sport uses a conventional plug.

Next there is ARMSPORT a importer out of Miami Florida. They imported CVA style guns from Spain after the demise of the traditional CVA line. They also imported Investarms style rifles from Italy though not as finely finished as the Investarms or Cabelas offerings.

JD says

Since it's Spanish, more than likely you are going to need to and should replace the assembly, I.M.H.O.

The reason for this is the way the Spanish made their barrels. The plugs were a spun or jammed fit by machine. Once removed it is nearly impossible to get it back in spec as it was assembled by machine.

 

[M. De Land]

Is the thread and shank tapered? Mike D.

 

[tx50cal]

It appears square.

 

[crockett]

Thanks Zonie on that explanation of wear. I knew you weren't suppose to be taking a breech plug out but I never knew why. On the repair: I have NO IDEA if this would work- I'm just thinking- but if wear is the problem could the face of the plug that meets against the shoulder be stuck with a center punch to dimple it, there by increasing the length where wear has shortened it and then screw it until tight? This dimpling would be multiple hits around the outside of the face, creating sort of a pebble appearance.
Just a thought- I have no idea if it would work.

 

[M. De Land]

The dimple idea would not be a good remedy. I would personally just make a new one and fit it up properly.
My guess, having fit a few personally and fitting many barrels to actions on center-fires, which is the same mechanically speaking, is that the shoulder was not a crush fit in the first place.
Another possible remedy that I have not personally tried would be to make a lead crush fit bushing to fill the space between, extrusion into the bore after turning the plug fully in can than be trimmed with a brass scraper used to clean the breech plug face.
The reason plugs and barrels move in farther with repeated removal is one of thread stretch more than any other cause.
Any thread carries about 70 percent of the load over the first three turns initially and over time as pressure evens the load out they set back slightly. That is the reason for tight threading or ramped threading to more evenly distribute the load over the threaded shank length in the beginning.
I see the same thing routinely when fitting a new octagon barrel to an action and having to torque them up and remove several times until all fit up properly.
Take down guns have to be fit in this manor and even they will loosen up over time and use. Mike D.

 

[tx50cal]

Would the soft lead be hard enough for the pressure. I can see where the soft lead might ooze into any space that wasn't 100% sealed by the plug and barrel fit. I think that may be a possible repair. What do athers think?