Beware buying used parts that have been worked on...........

[Bigmon]

I'll try and keep this short.
My cousins son is trying to get into BP shooting / re-enacting.  But like most of us and especially when young is trying to do it as inexpensive as possible.
Anyway he bought a component set that someone had been working on and asked me to help him with it which I am happy to do.
After seeing the parts at a shoot where he bought them I told him it would be allot of work.  There was a whole lot of horrible work done but it would save him a little money so I said I'd help.
But while I was driving home and thinking about it I thought that when he got to my house the first thing we'd do was pull the breech plug and check that out.
It is a GM barrel and I didnt think they came already breeched?
The attached photos shows you how short the threads are on the plug.  A disaster waiting to happen??
The third pic shows the apprxzimate lines where the bad short plug ended and where the new plug extends to, which is now good and tight, and somehow came right up perfect on the original to flat.  As he also had two tenons inlet on the bottom flat.  Very poorly also, and no-where near the correct location.
There are allot of other problems with this gun build, but none that will do what this might have done if we had not pulled that breech plug.
Just the overall poor work done on the gun made me suspicious.  Glad we checked.
I may be on here pretty often asking advice on how to fix some of these problems.

[David Rase]

Correct breech plug installation seems to be an all too common issue.  Just today I pulled a breech plug on a barrel to inlet into a stock blank for a client and discovered that the center line of the bore diameter does not line up with the center line of breech plug diameter.  A little bit of misalignment is not normally a problem but due to the 28g bore diameter and the use of a 5/8"-18 breech there was no room for error.  The seating surface for the face of the plug on the barrel is crescent shaped meaning there is no seating surface on the barrel on the left side for the breech plug to seat on.
David

[thecapgunkid]

This is a very interesting post because there are so many hazards with the Black Powder Guns.

I've always been amazed at the amount of muscle needed to tighten and loosen these bad boys, and have heard so many stories of disasters but have never seen one at the range.

When a breech plug is short like that, what is the threat?  Does it blow out the vent?   Does the whole thing split?

I just saw one of my very first rifles ( a medal and ribbon winner all the time) come back to Dixons thoroughly abused where, among other things, there was a brass braized gap between the tang and barrel.  Broke my heart to see it

There seems to be a lot of new guys making posts here, and a point of reference is most likely needed.

Thanks

Capgun

[Elnathan]

That breechplug is what, about 3/8" of an inch?  That is on the short side, but I think that the original barrel and plug I have are no longer. The real problem would be if it didn't seat against the shoulder.

Back in "the day" people were able to pull their breechplugs to clean or drive out a bad load, and I doubt that they had a workbench, vice, and special wrench to do it with.

[Ky-Flinter]

On buying used parts or an unfinished gun, sometimes you get a deal, sometimes not so much. 

Bigmon,
You were right to pull the breech plug to have a look.  In my opinion, 3/8" is too short.  Several of the current production barrel makers install a 1/2" long plug.  I think Green Mountain breeches are 5/8" deep, but they don't supply the plug, if I remember correctly.

I pull the plug on every barrel I acquire and check the fit, even brand new production barrels from known makers.  More often than not, I will "improve" the fit.  Maybe I'm just picky.

-Ron

[Ky-Flinter]

When a breech plug is short like that, what is the threat? 

I think the 3/8" length does not allow for enough thread engagement.  1/2" length gives 33% more engagement.  But I agree with Elnathan, the breech plug face seating against the shoulder, all the way around, is the key.

-Ron

[Hungry Horse]

I suspect the old timers rarely pulled the breech plug on their guns to clean out the breech, or remove a stuck ball. They did remove the breechplug to periodically freshen the rifling, because wrought iron is soft, and wears rapidly.
 The current use of national fine threads for breechplugs wasn't as common in the past. Years ago I fell into a deal, and became the owner of a couple of dozen old muzzleloader barrels that had gone through a fire. More than half of them had heavy course threads.

  Hungry Horse

[deepcreekdale]

I think Elnathan is right but you were correct to get another breech plug anyway. Not only is that thread on the short side but also the tang bolt hole is way off center. You could cut off the tang and silver solder on another one but that might be above a beginner level. Breech plugs are cheap. I like my breech plugs tight and seated on the shoulder but not so tight that they don't come off without excessive effort. I am not a machinist but I used to race vintage motorcycles and remember learning how overtightening threads actually weakens them greatly. Perhaps some of our metallurgist and machinist members could weigh in on this?

[Bigmon]

After I tightened the barrel in my vise I made a good fitting lead cover for the plug bolster, fit my big wrench on there and got ready for a heave ho.  But it was already only slightly tite.
It was only tite against the back end of the barrel, bot the inside at rge face of the bore.
I dont know if 3/8" is enough, or 1/2" or whatever.  I just know ya cant have exposed female threads inside the barrel.  The plug has to come up tite.  It does now.
I also suspected it was too short cause before I pulled it I put a cleaning rod down the barrel and marked the inside length.
Once I put the correct plug in then the face of the plug was forward the pan on the lock which the "other person" has already mislocated and inlet.
So, I had to fill his tang inlet and I moved the barrel back about 1/8" adn re-inlet the tang.
This ofcourse moved his barrel pin locations, which were very poorly spaced anyway so I am going to redo all that for my cousin.
Once I got the tang in I discovered that this guy had removed too much wood from around the top and I will have to do something with tthe tang and that area.
It is almost down enough and I think I will just "humor" the tang down to grade and maybe a little bevel??
There are allot of problems with this.
I offered to loan him the diff and let him work it off as I need help at home with allot of my own chores that require lifting, bending, spading a garden, etc.
He didnt seem too impressed with that idea.
Thanks fer yer advice and opinions.  I always check and see what ya'all have to offer.

[Cory Joe Stewart]

Yeah I learned the hard way to check even new barrels.  I have gotten two barrels from a well known company and both had exposed female threads.  The last one I was able to turn the plug a full rotation to get a tight fit. 

Cory Joe Stewart

[Majorjoel]

Just want to add to this very important post.

A lot of the unfinished parts sets you find on the market come from beginners that started a project and screwed it up.

They tend to pay the current retail price for the "kits", make whatever progress on it and when things go south they put it up and it may sit around for years.

Memories fade and all that is left is the dusty sales slip on what it cost.   

When it re-hits the market for what looks like a sweet deal, the next owner gets reamed.