Heads up: breech plug not reaching the bottom

[whetrock]

I bought a barrel and precarve recently, second hand off eBay. (This is the same G.R. Douglas XX that I mentioned in another thread.) Someone had already inlet the tang of this barel, installed lugs, and drilled the lugs for pins. When I pulled the plug, I discovered that the plug did not bottom out against the shoulder. This left almost 1/8" gap and exposed threads between the end of the plug and the shoulder. Of course this is not acceptable and it creates a huge trap for fouling. I'll need to fit the breech plug properly, and will probably lengthen the dovetails and make some longer lugs, so as to be able to use the pin holes already drilled in the stock.

So I'm posting this as a "heads up". Think of it as a public service message. If you buy a barrel already fitted with a plug, be sure and check it yourself. Don't assume that everything is perfect. Sometimes it's hard to pass up a good deal, but you do have to do your own diagnostics once the thing gets to your shop.

Here's a rough sketch to help explain what I'm talking about.
 

[Birddog6]

That is unfortunate.  I check every single one that is breeched.  Not uncommon to get one that is not done properly. The Rice barrels will be a perfect breeching job, over 75 of them owned & checked & all were right on the money. The Getz barrels I have used were good fit to the bore.   I never trust ANY barrel maker though, I check them all I buy personally. Don't want a error there.

Some guys think ya screw a plug in & align a flat & it's done. Depth of the plug & proper fitting to the flat & the bore face in the breech is essential.

I would rather pay full price someplace, than half price on eBay.  It is usually there for a very good reason most of the time.

[Bob Roller]

if you have a lathe a thick washer can be made.Use a depth gauge,maybe a dial caliper and find the real depth of the threaded hole and then use it to find the real length of the threads and the difference will determine the thickness of the washer/spacer'The hole in the washer should be bore diameter.
Bob Roller

[45-110]

Set the barrel back so the breech plug seats, then slot the lugs for keys. Option 2 is a longer breech plug.

[Spalding]

Here’s the breech face of an older NOS barrel that had a breech plug installed that I bought a few years ago. And after cleaning up with a cutter I made ala Dpharris.
I can only imagine what would have collected in there if not fixed.
Bob

[kutter]

If the bbl threads are a common size and I assume they are, large dia 'set screws' are made that will fit in it.
They have a large Allan Wrench drive so you can tighten them down well.

Take one of those and shorten the face of it so when seated down in there, it leaves you enough of the orig threads to then seat the breech plug in behind it.
 The breech plug will then be just an accessory for the 'tang', but necessary none the less of course.
It will not need to be fitted at the front of the 'plug' as before as it isn't sealing the bore. The 'set screw' will be doing that.
The breech plug will only need enough thread engagement to make a sturdy assembly of it to the bbl.

The Set Screw will need facing off to a shorter length to give you room for the shortened breechplug thread.
Figure everything including the depth of the Allen drive in the back end of the Set Screw so you don't leave that inside wall too thin.

This re-make of the breech plug allows you to leave the bbl pin slots and everything else alone.

Those Allen Set screws are generally very tough steel as well but not so hard that they can't be worked with hand and machine tools.
If it's a little too hard to easily work,,just draw it back a bit.
The bbl is likely only 12L14, so the plug that seals it up at the breech needs to be ...?

[Birddog6]

Let's back up just a minute, just for fun..

Just take a piece of bout anything & stick it where that breech plug goes in & go to the bore seat & hold it against the seat & mark the end of the barrel on yer stick.
Now take that stick outside of the barrel & align the mark on the stick to the end of the barrel & mark the end of the bore seat on the outside of the barrel.  Now you know where the seat will be.
Now align that mark to the Center of your Flashpan, or where your Drum will be.

You need to attend to that First.  If you have to move the barrel back then we go that direction. If not we change the breechplug to the Correct plug & go on.

I suggest you DO NOT patch, shim, washer, whatever the breechplug.  Do it Correctly & put the correct plug in it.  Why patch & make more parts inside, maybe gaps you can't see, & more places to hold water & rust ?   I am for  Do it One Time & Do it Right.

Give me the Dia. of the Plug (where it threads in the barrel / 1/2", 9/16", 5/8", 3/4 prob)
Depth of the threaded breechplug hole in the barrel. (Like prob 9/16" or so from outside to bore seat)
Width of the flats (Need to match the tang width to the barrel flat width)
Length of the tang you have inlet.

I have a whole cigar box of breech plugs as I always kept spares. Sometimes pull one & make a Ove-the-Comb tang & etc. & just tossed them in this box, some of them are New as I always have extra.

If I have the correct one I will give it to you.

Now you WILL have to make it fit & seat it & clock it & etc.  But that is how this should be fixed.

Or you can trim the barrel & plug you have, but don't put washers or shims in it.

I am not saying you cannot shim & space & etc. All of those are great ideas.  But to me the
correct way to address the repair is start with the Correct Part.  And that is a longer breechplug.

Your mileage may vary.

[whetrock]

Thanks for the suggestions, guys.
Yeah, Birddog6, I agree with you that just reseating the plug is the best way to go. (Thanks for the offer of a new plug. I have some spares as well and if this one won't work for some reason, I should have one that will.)

In this case, the threaded hole is longer than it needs to be anyway, and the plug that's in it is also a little longer than it needs to be. So I'll trim the barrel down and trim the plug a little and reseat the plug. Not a big deal. That will give me proper lock placement.

The work on the lugs is not a big deal. The lugs that are in it now are very short, barely adequate brass lugs. I'll replace them with steel lugs. It's not hard for me to make and install new ones. It's a Lehigh precarve and straight octagon barrel, so I'm gonna stick with pins and a late Leigh plan something similar to what Lead Snowman posted here (See link below). Just want to keep it cheap and simple.

Note that the barrel on that antique is not swamped. That's one reason I like that antique for this project. I picked up this combo (smaller Siler, Douglas barrel, messed up precarve) for about $300 plus shipping. Not wanting to sink any more money into it. I can make the parts I need for this simple rifle, and that's a plus. So, we'll see how it goes. If it turns out pretty, I'll post photos. If it turns out ugly, I'll keep my tail between my legs and my mouth shut. 

https://americanlongrifles.org/forum/index.php?topic=85357.msg834674#new

[Birddog6]

I have used slotted underlugs on the last? 25 rifles I guess. I was making them & drilling them & then
making the pin hole elongated.  Then on several rifles I had taken apart that were built a long while, almost every one had bent pins where there was no room for the wood to move. So I started buying the slotted ones in bulk & save myself allot of work. 
Sounds like you have the breechplug issue thoughts going right.

Don't worry about messing it up.  1st one is supposed to be ugly, so you have one to look back on.

Suggestion:  Just work on it when you feel your best.  Getting tired & frustrated will cost you work & $

[whetrock]

Thanks, BirdDog6,
It's not my first, but I appreciate your encouragement and the time you've given to all of us with helpful input and advice. I'm glad you are back on the forum!
Whetrock

[A.Merrill]

That's odd. I used many Douglas barrel and the breech plug threads was always longer than the breech was deep. Why don't you buy a plug that fits. You can always refit the tang.   Al

[elkhorne]

Whetrock,
Birddog6 has given excellent instructions but if you check Bill Raby’s videos on Rumble, I believe it was on his first 4 Bore build that he shows exactly how to properly seat the breechplug on the one of the videos. Just check on Rumble under Bill Raby and it has a good index of his builds for what each video covers. Good luck.

[whetrock]

Here’s the breech face of an older NOS barrel that had a breech plug installed that I bought a few years ago. And after cleaning up with a cutter I made ala Dpharris.
I can only imagine what would have collected in there if not fixed.
Bob

Bob,
Good work on the plug seat.
Years ago I had a similar problem on a barrel and Dan Pharris gave me the same very helpful instruction. He’s a clever fellow.

[whetrock]

That's odd. I used many Douglas barrel and the breech plug threads was always longer than the breech was deep. Why don't you buy a plug that fits. You can always refit the tang.   Al

Thanks, Al.
Yes, I could buy a plug that fits. That's an option.
When you say, "That's odd", are you saying it's odd that I view trimming the breech as a good option for fixing this? Or are you saying it's odd that the breech plug in it now doesn't touch bottom? (I'm not offended, either way.)
The poorly fit plug that came with it is too short because the guy who installed it cut it back too much. I measured it again this morning and it's actually only about 1/16" too short--not 1/8" as I said in my first post. Anyway, it's too short. I could buy a longer one and install it properly. Or I could trim the breech and properly seat this one or a similar one.

(edited)

[whetrock]

Whetrock,
Birddog6 has given excellent instructions but if you check Bill Raby’s videos on Rumble, I believe it was on his first 4 Bore build that he shows exactly how to properly seat the breechplug on the one of the videos. Just check on Rumble under Bill Raby and it has a good index of his builds for what each video covers. Good luck.

Thanks, Elkhorne.
Yeah, Bill has a lot of helpful videos. Thanks for the feedback.

[Leatherbark]

A suggestion. Go to a store and buy a Grade 8 bolt. Screw it in tight against the shoulder but first polish up the mating surface of the end of the bolt. Hacksaw off the bolt head and file the bolt so you can weld the tang that you remove from the old plug to the top of the new bolt that is now your breechplug.  A few hours work.  Maybe get someone to "V" and tig weld the tang to the new bolt where it will be hidden.

Bob

[bluenoser]

Assuming everything else lines up correctly, I'm with Bob.  It should be an easy and entirely adequate modification - especially if you have access to a lathe.

[Steeltrap]

If you go the bolt route (which is a good idea) you have an option to make a hook breech tang.

Just a thought.

[hudson]

I have been involved with three barrel with that problem all rifles Traditions. One a farmer brought in had such a gap that a cleaning patch balled up in the gap and he couldn’t with draw the cleaning rod. A spacer was made in all three to fill the gap problems solved.

[Birddog6]

We are all spoiled.  Getting barrels with fitted breechplugs & perfect fits & etc.

Yesterday (so it seems  ) one was not this lucky & ALL of these breechplugs had to be fitted.

So, you say the plug is about short 1/16" now. (Less than initially guestimated)   

Just file 1/16" off the barrel & refit the plug & go on.  Buy or make 2-3-4 as required slotted
underlugs, install them,  & you are in business again.

I think it is a normal ML build task.  It just should have been properly executed previously
as the barrel & tang are inletted.  It wasn't, so you back up & fix the Boo-Boo & go on...