Smoothbore reline question

[jonk]

So what does relining a smoothbore actually mean? It sounds straight foward, but my questions are these:

The walls on a smoothbore, particularly an original, are pretty thin. To keep the gun skirmish legal, it has to be more or less the original caliber, with a few exceptions (lining a potsdam to 69 for instance). Now, if someone has a cut down gun, lining and stretching is easy enough, as the bolster/rear area of the barrel is thick enough to ream out and install a liner, that is stepped to allow restoration to full length. But what of an untrimmed gun that just has a lot of pitting in the bore, that someone wants to have relined? Does the barrel have to be chopped down to be lined? Or is there some way to put a liner into that thin bore that I'm not seeing?

My H&P has a lot of pitting. More outside than inside, but enough that it is a lot harder to clean up than my Potsdam or 42. I'd love to rectify that situation, but if it means cutting the barrel down I wouldn't.

[R. McAuley 3014V]

Similar to the link shown below, just a larger diameter liner sleeve.

https://www.youtube.com/watch?v=XZ7sQya7tyk

[jonk]

Interesting video, though it doesn't really answer my question: namely, confirmation that a full length sleeve CAN indeed be made without cutting back the barrel, even as thin as a smoothbore barrel is.

[gemmer]

Interesting video, though it doesn't really answer my question: namely, confirmation that a full length sleeve CAN indeed be made without cutting back the barrel, even as thin as a smoothbore barrel is.

Bob Hoyt did an 1816 smoothbore and a rifled 1842 for me without the procedure you describe. They're both .687 bore.

[jonk]

Exactly what I wanted to know! I'll take my 16 to him in the fall and see what he thinks.

[MR. GADGET]

You need some thickness to the end of the barrel or you will just be doing the same as a line and stretch.
many 1842 barrels are paper thin at the end. There is no way you can line that with the thin barrel and not cut it back to the min thickness to drill and hold the liner.
That is the main reason they back it up to one of the bands or only use 50% of the barrel.

[R. McAuley 3014V]

Jonk,

What is the outside diameter of your muzzle, and what bore diameter would you like to see? Bobby is rather difficult to track down on the BB, but Dan Whitacre uses the BB frequently, and you could ask him directly anent his recommendation. Is the Potsdam not normally about a .723 inch bore?

[John Bly]

Bobby can line a full length 42 barrel. He drills them out to .770 which is enough smaller than the muzzle diameter to work well. Generally some pitting can be tolerated in a smoothbore barrel. Large craters are a problem though. A lot of smoothbore barrels are eroded at the breech end and are rough enough to pull cleaning patches off the jag. Many are eroded as much as .025-.030 oversize at the breech end for several inches. These are best lined. Bobby recently did a 30 inch Macon barrel for me that had been reamed out to 10 ga.. He only had about .020" to work with to clean up the bore for sleeving but he got it done.

[jonk]

Jonk,

What is the outside diameter of your muzzle, and what bore diameter would you like to see? Bobby is rather difficult to track down on the BB, but Dan Whitacre uses the BB frequently, and you could ask him directly anent his recommendation. Is the Potsdam not normally about a .723 inch bore?

I'm actually out of town right now, and will measure it when I get home. Remember, this is regards an 1816 H&P. I only gave the Potsdam as an example of one of the few cases where a modification outside the 'one caliber either side of the original' was approved as a process. I also DO have a Potsdam, and for what it's worth, my bore is around the dimensions you list, and I shoot a .715 ball in it.

Beyond the pitting, part of the reason i'm interested in lining the 16 is, i call it "the world's most beat-up H&P." It has the oversized breech area someone referenced, leading to pulled patches. There's rather a lot of pitting on the bolster and rear end of the barrel OUTSIDE too, which while it has never given me issue, I'd love to have a liner of modern steel inside for piece of mind.

[R. McAuley 3014V]

Having an HP relined should not be a problem, and cosmetically, after it has been fired a few times it is difficult to even see the seam at the muzzle. As for the pitting around the bolster and elsewhere on the exterior maybe you should look into having it electroplated with iron. Although most people think of electroplating with copper or nickel, iron plating was used in World War II to conserve copper and nickel, and hard iron plating was used to plate aluminum pistons to enhance wear resistance, and to eliminate the need for iron and steel sleeves. I'm sure there are some other metallurgists here who can add to this, but this might be an alternative to relining though much depends on the thickness required. A nice advantage of electrodepositing is that you can better control just what areas are deposited upon and by how thick, so this might be a method for improving the pitting around the bolster without plating the entire barrel and increase its wear resistance to corrosion. Just a thought.

[jonk]

That's an interesting thought. Electroplating it, I mean. When you come down to it, I doubt any of the pits are even a millimeter deep, as they just BARELY obliterate most of the breech date (though you can still see the "62" part of the 1862) and my thought process when choosing to shoot the gun was simply, "there's nowhere near even 10% of the metal gone, and I'm nowhere near 90% of a max charge, or even combat charge." But maybe down the road electroplating it would smooth it out a bit.