Checking caliber on unmarked ML rifle?

[DonP]

I picked up a very nice looking ML yesterday at a local gun shop. Consignment sale by the daughter (40 yo or so) of a now passed on (God rest his soul) shooter that had it as a wall hanger for the last few years.

All she knows about it is her grandfather used to shoot it, her dad hadn't shot it in years and that's it.

The only marks on the barrel are large letters RON POE, which I'm guessing is an owners name, no caliber indications. Nothing on the lock that I can find. Percussion lock, with a 42 inch barrel 58 inch OAL, no wedges, just pinned in place like most Kentucky's I've seen, double set triggers with a straight firing trigger in front and a small screw to adjust the triggers between them.

It has a beautiful tiger stripe full length Kentucky style graceful stock (pictures to follow), like a lot of older museum and custom pieces I've always admired. The store thought it was a .50 but when I got it home and measured the muzzle at .440 so it seems to be a .45.

I'm new to ML, with only a Cabela's Hawken in .50 that I've played with. Assuming I want to shoot it at some point, what's the best/safest way to determine the caliber and twist rate? Should I disassemble to check for rust under the barrel and the inside of the lock, or just clean it up? Anything specific I should look for? No visible rust except for some light pitting around the end of the muzzle.

As always, any help or re-direction is appreciated.

 

[GCBurner]

If it were mine, I'd cut a thin triangle out of card stock and insert it in the muzzle, scribe a line across the diameter from land to land, and measure it with my dial micrometer. Then pick a round ball about 0.01" smaller, and find a patch thickness that offered a good tight fit. If it's a standard, commercially made .45, there should be a reference from the manufacturer as to what the twist rate is, but if it's a custom job, it could be faster or slower, depending on whether it was made for round balls or conical or sabot bullets. Green Mountain barrels, for example, are rifled 1 turn in 70" for roundball, and 1 turn in 28" for sabots.

 

[Don McDowell]

Ron Poe is the maker.
I would pull the lock and see that there's not a lot of corrosion , and then get some 440 round balls and .015 precut patches, load it with 45 grs of 3f and see how it shoots.

 

[jgh4445]

First thing I'd do is to check and make sure there is no charge and ball in the barrel. You can use the ramrod to measure with. Lots of these old guns were stored loaded for one reason or another.

 

[mykeal]

First thing I'd do is to check and make sure there is no charge and ball in the barrel.

Very good advice.

pull the lock and see that there's not a lot of corrosion

Also good advice.

Then remover the barrel (carefully!) and check for corrosion.

Next, while you have the lock and barrel out, apply a couple coats of boiled linseed oil or Tru-Oil to the interior wood surfaces. Let it dry thoroughly. This will seal the stock and prevent dry rot, the wood equivalent of corrosion.

Twist rate: run an oiled patch down the bore to thoroughly coat it. Then put a couple of dry patches on a cleaning jag that's just undersize from the bore diameter. You want the jag to be tight in the bore but be able to slide without a great deal of effort. Run the jag down to the breech and wrap a piece of tape around the rod at the muzzle; leave a tail on the tape so that is sticks out like a flag (it's a good idea to make the flag stick out at the front sight). Note the location of the flag on the muzzle (if it's at the front sight...). Slowly pull the rod out allowing it to rotate until the flag is opposite the starting mark. Put another piece of tape on the rod at the muzzle. Fully remove the rod and measure the distance between the flags. Multiply by two and you have the twist rate; for instance, if there's 24 inches between the flags the twist rate is 1:48.

If the rod comes out of the barrel before the flag reaches the 180 degree mark simply start over, but stop at 90 degrees of rotation, and use 4 instead of 2 in the multiplication.