Interesting Project: .62cal "Rifled" barrel

[roundball]

Thought I’d share an interesting project with you…

I have a GM .62cal 1" x 33" drop-in Flint smoothbore barrel for a TC Hawken…had it jug choked for turkey hunting…terrific barrel...liked it so much I decided I wanted a .62cal "rifled" Flint barrel for deer hunting and discussed it with Ed Rayl in West VA., then sent a new GM .62cal Flint smoothbore barrel to Ed in January to cut his recommended .012" square bottom grooves in it with a 1:72" twist.

Got it back a couple weeks ago and took it to the range 3 times for load development, experimenting with 80/90/100grns Goex 2F and Eddie May (GA.) .600 cast balls, .015"/ .018"/ .020" patches, with and W/O .62cal Oxyoke wonderwads, etc.
(For those who may not know it, a GM .62cal bore diameter is actually .610”, not .620”)

.018" lubed pillow ticking with Oxyoke wonderwads gave the tightest groups...and it seemed that each successively larger powder charge was more accurate than the one before it with 100grns Goex 2F being the most accurate of the three, significantly so.

100grns gave single ragged holes for 5 shot groups at 25yds, and slightly larger ragged holes/cloverleafs at 50yds...so I stopped at 100grns as it’s plenty for deer hunting in the North Carolina woods. Also, I thought it was interesting that the step to 100grns produced a different sound, a sharper rifle 'crack' it seems like...and the impact of that 325grn ball was very evident when it hit the dirt berm behind the target.

100grns Goex 2F
.62cal Oxyoke prelubed wad
.018” Oxyoke prelubed pillow ticking
Eddie May .600 cast ball

Ed Rayl did an outstanding job with the rifling & crown, as well as the exterior...no indication whatsoever that the breechplug was removed, the barrel rifled, and the breechplug reinstalled except for his 1/4" witness mark added underneath on the bottom flat at the breechplug/barrel seam...hard to believe that kind of quality & precision is available for $65.

I've put about 150 balls through it...it loads smoothly, fouls little, and is extremely accurate so he may have even polished it a little after cutting the rifling. I know it’s a lot of caliber for eastern whitetails at woods distances but it was an interesting enjoyable learning experience...cleaned & polished it up showroom ready, dabbed white paint on the sights, and put it up...ready for hunting season.

May have started a little fad with this conversion...3-4 fellow muzzleloaders have ordered themselves GM .62cal smoothbore barrels to do the same thing...another reason for posting it here in case anyone else might have a similar interest.