To bore or not to bore...

[wildcardranch]

...I'm thinking of buying an extra barrel for my Lyman GP rifle and then having it bored to .58 cal. Does anybody know if the barrel and breech plug are substantial enough for this move?

 

[Semisane]

I really don't know if there's enough meat in that 15/16" barrel for a .58. The Green Mountain barrel company only goes up to .54 in their 15/16" barrels. Their .58 barrel blanks are 1".

At any rate, it would be a pretty expensive project. You might want to locate someone who would be willing to take on the job and see what it would cost before buying a barrel.

 

[Jim Buchholz]

I remember reading something written by Sam Fadala,whom I consider to be an expert,about that distance across the flats/bore size relationship. IIRC he put .54 cal as the max safe bore size with a 15/16 barrel. I agree as it would seem the walls will get quite thin after that.On the other hand I've seen it done without ill effects to the gun or the shooter.

 

[sundog]

Investarms the maker of the GPR used to sell a .58 15/16 across the flats in their trade rifles. Cabellas sold them under the Cabelas name.
I have one in flint and one in percussion. I like them with patched round balls.
If you can find one of those barrels and youcan do some work on it, new barrel lugs , cut down the underrib you will have a .58 barrel for your GPR. The trade rifle barrels are only 28 inches long as opposed to the 32 inches for a GPR barrel BUT you will have a much lighter rifel that is fast handling. A great hunting rifle.

 

[roundball]

...I'm thinking of buying an extra barrel for my Lyman GP rifle and then having it bored to .58 cal. Does anybody know if the barrel and breech plug are substantial enough for this move?

It wasn't clear to me if your rifle is a 15/16" or 1" barrel so this suggestion may not work at all if your Lyman won't accept a 1" barrel.

But if it will, I wonder if it might be simpler and possibly cheaper, to buy a TC .58cal x 1" x 28" x 1:48" or a GM .58cal x 1" x 33" x 1:70" drop-in for a TC Hawken, then send it and the stock to Ed Rayl in West VA (or some good gunsmith) to have him make whatever mods are required to drop into the Lyman?

Do you have access to a TC or GM barrel to compare with the Lyman barrel and see what would have to change on a GM .58cal barrel?
ie: Wedge pin tenon location and tang?

In my case, I found a used TC Hawken stock that had a lot of good figure under all the grime, picked it up cheap, refinished to a beautiful stock, and dropped in a GM .58cal RB barrel...an outstanding rilfe for sure

 

[BrownBear]

I've got a rifle with the 58 cal barrel tapered to 15/16" at the muzzle. But it's 1 1/8" at the breech. I'm betting that the loss of 15/16" 58 cal barrels from the market was due to lawyering and the concern for potential bursts from overloads. Right up there with McDonalds coffee in the lap. Even so, I bet you'll have trouble finding anyone that will build a 58 x 15/16" barrel, much less do the rebore of a smaller cal. I guess if I needed to worry about it I'd be looking at the rear sight dovetail and how thin the metal would be, then locate the rear sight as far forward as you're comfy with.

BTW- On the question of hogging out the stock to make more room for the barrel, my rifle evidently started life as a 15/16" TC Hawken. Lots of hogging going on back there to make room for that 1 1/8" breech end, but whoever did the work managed to pull it off. The wood is real skinny in a couple of spots around the lock plate, and I probably wouldn't have bought the gun in the first place if I had popped the barrel beforehand. (Note to self.) But it seems to hold up fine, even if it's a little scarry lookin down there.

Another BTW- For whatever reason, the smith opted to use a 1" tang (fixed) rather than a 1 1/8", so there's a definite step betwee the breech and tang. Makes me speculate that the smith wanted to keep a little more wood in the tang than would have been possible with the next size larger.

Hope my observations and speculations of an existing conversion help.

 

[rice1817]

Getz is offering an "ultra light" 50 caliber barrel in 13/16th! Don't know what they are putting into steel these days, nor how deep one can cut dovetails into it, but that is getting mitey thin. Apparently, if you do it right it works.

 

[wildcardranch]

Excellent information. Thanks to all. I may just have an excuse to pick up a whole 'nother firearm. Funny that. Thx again.

 

[Leatherbark]

Dang.......Pedersoli makes a Blue Ridge in .54 with a 7/8ths in barrel. Not much meat there for sure....................Bob

 

[Jim Buchholz]

That barrel is indeed on the light side. I wouldn't stuff a heavy charge in it.

 

[tg]

If the barrel is 15/16 I would question how many threads you could grab with the liner or drum, it seems light to me, but if they are producing .58 guns with a 15/16 breech someone must feel it is a good thing.

 

[brubincam]

-----there are 62 cal. barrels that are 1 inch--would this be any differant than a 58 cal. in a 15/16 barrel-----

 

[tg]

Probably not, and this also seems a bit light to me, I guess I just lean towards a little more meat at the breech, I would think that with todays steel and the typical law suit driven consumer product era in which we live if there were even a hint of a problem the bore sizes and barrel thickness would be different, also I have no idea if the wall thickness needed is proportional as the bore size increases.i thought that the .58 and .62 were usually bored in a 1" tube, I like a 1/1/8 breech for a .62 (swamped) and my .58 is about the same at the breech as it is the same profile as the .62 in that makers barrel, these are both smoothbores.

 

[Mad Professor]

If the barrel is 15/16 I would question how many threads you could grab with the liner or drum, it seems light to me, but if they are producing .58 guns with a 15/16 breech someone must feel it is a good thing.

Investarms/lyman offered a 15/16 plains rifle in 62 cal smoothbore and Toledo made a 12ga 15/16 drop in barrel for the TC which has about the same tang as lyman/investarms.

I've got 1 of each and have not had any problems with either.