Touch hole liner question

[aragorn]

My first attempt at posting a photo.

I'm just in the process of installing my touch hole liner. As you can see, it comes out partly in the breech interior, which is wider than the barrel interior (the picture is a little misleading, as only about 1/4 of the liner is in the breech).

The liner is perfectly positioned for my lock and the barrel is as far back as it can go in the stock, so there's no problem there.

How do I deal with this?

1) I could file away the bottom of the liner. Problems: messing up the liner threads, and reducing the thickness and strength of the liner. On the bore side, as you can see, the liner is well within the barrel wall thickness, so it's only the breech side that's a problem.

2) File a space in the breech plug face. I'd have to do the usual notch anyway, and could just make it bigger to accommodate the bottom of the liner. Problem: avoiding creating small gaps that could accumulate fouling.

Do barrels generally get fitted with a breech plug that's wider than the bore (this one's a Rice 50 cal, which came with plug installed)?

I'm just worried about doing something that might weaken things at this crucial point.

All advice greatly appreciated!

 

[hootal]

It would appear you may need to cone the side of the breechplug face, too. Use a magic marker and blacken the exposed liner. Remove it and file that portion away. It will not damage or weaken the liner.

Here is a link to a page I put together on this subject. Hope it helps.
Link: Installing a Touch Hole Liner
Hoot Al

 

[Vaino]

You'll have to file off the portion of the liner that protrudes into the threaded breach because even w/ a coned groove in the face of the plug, the plug can't bottom out because the liner will hit the face of the plug when it's being screwed in. Read the following response and a coned groove in the plug face will be necessary to give the powder full dia. access to the liner.

 

[hootal]

I agree. That's why I said to mark it with a marker before removing the liner so you can see what needs to be filed away. However even with the liner filed away, the breechplug will cover half the hole of the liner.
Hoot

 

[aragorn]

Thanks very much for this.

I'll start by filing away that exposed part of the liner, as you both suggest, then move on to filing a cone in the breech face.

I was hesitant about filing the liner because I didn't know if this would weaken it. But having thought about it, there's no way I could file a big enough chunk out of the breech plug anyway without making a mess. Also I'd never be able to remove the plug again if I went that route.

On the picture in your link, I see the breech plug diameter is the same as the bore, whereas my plug diameter is bigger - hence the problem, or rather my uncertainty how to proceed. I'm still wondering whether mine is an unsual setup.

 

[Vaino]

The threaded dia. should be larger than the bore dia. so there's a shoulder for the plug to shut off on.Various brands of barrels have different combinations of plug dia. vs bore dia., but a shoulder of some size is mandatory. The Colerain .54 cal. has a 5/8th plug dia. which yields a very small shoulder, but it's still there.......Fred

 

[aragorn]

Thought so - thanks. I wish I was able to see more first-hand to compare, then I wouldn't have these basic questions. The forum is a lifeline!