White Mountain Carbine

[excess650]

I just picked up a White Mountain Carbine, .50cal percussion without knowing what twist it was. I checked it with a tight patch and saw 1-16-1/2" on the first try and 1-17" on the 2nd so its definitely a fast twist barrel. To be honest, I was hoping for a 1-38". Regardless, I shot it a bit today and its showing promise with 70gr fffg under the 250gr REAL. Other conicals are either too hard to load, or didn't group well. The sabots I tried were really tight, so I'll have to experiment and see what will be more manageable.

Just for S&G I decided to try PRBs. I set the measure to 50gr and loaded a round with what felt too loose of a combo. I tried a thicker patch and was rewarded with snake eyes for a pair of shots at 50 yards. I'll revisit that later....

 

[cayuga]

According to the T/C Barrel Chart.. in .50 caliber that rifle has a 1-38 twist. In .54 caliber it is a 1-38 twist. I shoot a Lyman Great Plains Hunter that has a 1-32 twist and it does a real good job with roundball.

Have you tried big conicals? Like a 450 gr or bigger?

 

[Edwardamason]

The Early model WMC had a 1-20 twist then they went to a 1-38 twist. Sounds like what you have is a 1-20 twist. Congratulations you have the holy grail of the TC line. Everyone is looking for one of those.

If you are looking for a sweet sabot load look no further than the .452 250 Gr bullets. The best sabot I found was the MMP short black sabot. All the 44 cal stuff shot grapefruit rounds in mine.

 

[excess650]

After giving the barrel better cleaning, I see quite a bit of lead wash on my patches. THAT is likely the reason the sabots were sooooo hard to load. I need to get a short range rod for this one, and it would be better for the slightly longer Grey Hawk barrels as well.

Heavier conicals? I shot a few 320gr REALs, a few 370gr Maxiballs, a few 385gr Great Plains, ONE 385gr Buffalo Bullet, and a few Lee .476-400gr.
This latter conical may well work if paper patched with the correct thickness paper. I tried a Chase patch with cotton, but it was too hard to load.

This carbine has a pretty nice piece or walnut for the stock and doesn't appear to have been shot much. I'll be looking for another barrel, just because....1-38" twist .50 to be different and a .54 would be nice. Did I mention it has the hunting peep sight? My eyes and barrel sights aren't a good combination, but a peep sight really helps. I will NOT put a scope on it!

The reason for using the lighter Lee REAL was the short barrel. I figure that with a lighter conical and fffg, I should get reasonable velocity for hunting to at least 50 yards. I WILL try to find a combination to make a PRB work. It may take a light powder charge, but for shooting target and small game, it will be enough.

 

[excess650]

I've shot the WMC a bit more. Several sabot combinations from 250-300gr didn't produce any real consistency. I was just about to call it a day, but decided to revisit the PRBs. After a few shots at 60gr, I decided to do something stoopid. I loaded 90gr Goex fffg under a .490" Hornady wrapped in .018" pillow ticking. It shot sub 2" at 50 yards! I would never have guessed that a heavy load would work in this quick twist.

 

[cayuga]

Well fast twist barrels can shoot roundball. And depending on the depth of the rifling, its hard to say whether they will shoot a roundball until you try them. I shoot roundball out of my Knight Rifles all the time.

That load you mentioned should be a good hunting load.. that will put a whitetail on the ground.

 

[excess650]

I shot the little bugger again yesterday, but couldn't get the consistency I was looking for with PRBs. I tried saboted 280gr and 330gr over 90gr fffg and it grouped OK. So far 250gr REALs have been the most consistent.

 

[guitarpicva]

If you are looking for a sweet sabot load look no further than the .452 250 Gr bullets. The best sabot I found was the MMP short black sabot. All the 44 cal stuff shot grapefruit rounds in mine.

I'll vouch for that combo, specifically XTP's if you are hunting. Just devastatingly effective in the boiler room. My latest, an 8-pointer, went through and through and demolished his heart on the way. 40 yds. and down for the count.