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What size drum and thread needed

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Thunder14

32 Cal.
Joined
Aug 6, 2018
Messages
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Location
N.E. Pennsylvania
ok I’m needing some advice on what size drum and what thread size should i use.
THis is on a 45 cal Percussion 29 1/2 long barrel I have threaded the barrel to except my 5/8 w 1/2 D breech plug.Im going to have to drill into the breechplug for the drum do to I can not move the barrel back do to the lock screws.So should I go with the 1/2“diameter with 3/8-24 or 1/2”diameter with 5/16-18 Drum Or is there a better optio.This is my first Barrel build so Im looking for advice from those who know what there doing its not the time for me to go with trial and error,Error on my part could be a disaster.
 
Guessing this the same barrel you have started a couple of other topics on. Might have been easier to follow if it were one continuous topic.

How are the lock screws getting in the way? Is one hitting the back of your new breech plug? Need a photograph. If what others and I expect to see, you should be able to drill a clearance hole through the breech plus below the tang. Actually pretty common. How were the lock screws avoided with the original plug and tang?
 
Yes the breech plug is hitting the lock screw.I will have pictures tomorrow,this was the issue originally when they drilled the hole for the drum there was only 2/16th left on the back of the barrel which caused the barrel to split.If i do the patten breech style I will have only 1/8“ left on the back of the barrel where the drum goes threw.
 

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You need to set the barrel back enough so that the drum is ahead of the face of the breech plug, probably 1/4" to 3/8". Many holes have been drilled through the tang part of the breech plug. Can we see a picture of the barrel with the breech plug installed. You nay have to relocate the pins holding the barrel through the underlugs in the stock as well as the slots for the underlugs.

What you don't want to do is to drill your drum into the breech plug.
 
What you don't want to do is to drill your drum into the breech plug.
Agree completely. Put the power tools down for now. The advice about the drum location could not be stated any clearer than @Grenadier1758 does. Take and post the photographs requested. Then Grenadier1758 or someone else on the forum will walk you through the process.

How did your breech plug install go? Any difficulty getting it timed and seated on both surfaces?
 
Here are some pictures of what I’m working with.I have 1/4” to the lock screw from the front of the stock.I started fresh cut barrel again now its a new start.So I’m sure with guidance I will get this correct.I have to order a new breech plug I cut the last one so the the drum would be in front of it and only had 1/8 left into barrel which left me needing guidance of how to rectify my issue.
 

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I would never install a drum or a flintlock vent liner that close to the rear of the barrel.
If faced with this situation, I would move the barrel aft and extend the mortise for the tang as needed.
 
I have to order a new breech plug I cut the last one so the the drum would be in front of it and only had 1/8 left into barrel which left me needing guidance
In one of your other threads on this barrel I suggested you needed to get hold of a bottoming tap for the final threading of the barrel for the breech plug. The idea is to match the length of the breech plug threads to the exact depth of the tapped hole. When the breech plug is properly installed the face of the threaded plug will be solidly on the square shoulder of the half inch deep bored hole you cut in the barrel - the reason for the bottoming tap. With a chamfer on only the first one or two threads it cuts threads just about to the bottom of the hole, as compared to a regular tap with a chamfer on the first nine or ten threads. As the plug bottoms out in the tapped hole, the tang is lining tight to the back of the barrel, giving a tight fit in two places, if installed correctly. If you leave a gap at the bottom of the plug between it and the barrel you will create a tough place to clean and a real rag catcher when you run patches down your bore.

Based on you your statement about cutting your plug face back so there was only an 1/8” in the barrel, it sounds like you don’t or didn’t understand the concept.
 
I do understand about the breech plug, but I was told the drum had to be in front of the breech plug 1/4” the barrel would need to go back 1/2” at least And there is no way that’s going to be possible Do to the barrel would be into the lock screw.
 
The original plug had the old CVA style drum through the breech plug and it was only 3/64” from the end of the barrel,Maybe I’m just trying to make something work that cant be done.
 
I do understand about the breech plug, but I was told the drum had to be in front of the breech plug 1/4” the barrel would need to go back 1/2” at least And there is no way that’s going to be possible Do to the barrel would be into the lock screw.
Is the red arrow pointing to the lock screw that’s in the way of moving the barrel back?
1592939190438.jpeg
 
So you could move the barrel 3/8” without the screw interfering with the barrel? Is that enough to get you in front of the plug face?

Thinking about it a bit, as an option, why not just move the lockplate screw back a little? It will not interfere with anything on the back side of the lock (just checked, had an old CVA lock in the junk box, marked up photo below). Plug the old hole in the lock if you want, and make or buy a side plate to hide the hole in the stock on the left side, or plug with a round piece of wood and stain to match. Just make sure you don’t interfere with the tang screw when you move the screw.
1592940771178.jpeg
 
I would need to move the barrel 1/2” to have the drum in front of the breech plug.ya repositioning the lock screw is not an issue the issue is the 1/2” of stock needing to be removed.I just might take the 1/2” off the stock and see what happens from there.
 
Moving the barrel back will make the tang sit high. That means the barrel must be inletted deeper. That messes up the lock position. Quite the can of worms!

The best solution is to install a flint style chambered breech plug. Then put your drum in the side of that. You will have to figure out the barrel diameter and thread pitch. TRACK sells chambered breech plugs. They also sell a neat one for the TC Scout carbine with an integral drum.

If you have the original CVA metric threads you have a machine shop project.

Compromising the breech plug thread is a bad idea. I know of one maker of note who puts vents in the plug threads of flintlocks. The is in the minority. I think it is a bad idea. I am in the majority on that opinion.
 
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