The Bumblebee syndrome

[Muddly]

My T/C Pennsylvania Hunter flintlock, aka "The Bumblebee", because she seems to like things she ought not to.
Example. She's a .010 groove 1-66 factory ball barrel that, while still not shooting ball properly, does her best with .010 patches.
Well. In a fit of frustration, I decided to try some 250 grain Lee R.E.A.L.s, lubed with SPG, an Ox Yoke pre lubed wad and 70 grains of 3f Swiss.
They cut wadcutter type holes in the target. Clean enough to see the rifling! Not a hint of tumbling. Or leading.
3 shot 50 yard groups ran from 2 13/ 16ths to 3 7/16ths. 2 close and one out. Thus barrels going to be glass bedded as the inletting is a touch generous.
I think this load shows real potential.
It's more accurate, and consistent than ball!
This shouldn't be. Just like the bumblebee should not be capable of flight...

 

[azmntman]

Have a .36 CVA bobcat that will shoot NOTHING but a PRB using pine scented lube (HEAVY) and a thin as paper patch. inch group. A tight PRB will shoot a perfect shot gun pattern group. May steal yer name for this one HA

 

[hanshi]

Some times one just needs to cuss a persnickety rifle out really good.

 

[Spikebuck]

My .54 Pedersoli Rocky Mountain Hawken (still own) as well as a Pedersoli .54 Frontier I used to own, both with rather shallow square grooved 1-65 twist barrels, shoot/ shot conicals extremely well. But, they need(ed) to be hollow base. Patched roundball work well too. Like yours these guns shot them with no evident wobble at yardages in excess of 100 yards. I mostly used Hornady Great Plains conicals. All PRB now since they do what I need, but shooting conicals in slow twist barrels with shallower square grooves is certainly possible.

 

[Black Jaque Janaviac]

My T/C Pennsylvania Hunter flintlock, aka "The Bumblebee", because she seems to like things she ought not to.
Example. She's a .010 groove 1-66 factory ball barrel that, while still not shooting ball properly, does her best with .010 patches.
Well. In a fit of frustration, I decided to try some 250 grain Lee R.E.A.L.s, lubed with SPG, an Ox Yoke pre lubed wad and 70 grains of 3f Swiss.
They cut wadcutter type holes in the target. Clean enough to see the rifling! Not a hint of tumbling. Or leading.
3 shot 50 yard groups ran from 2 13/ 16ths to 3 7/16ths. 2 close and one out. Thus barrels going to be glass bedded as the inletting is a touch generous.
I think this load shows real potential.
It's more accurate, and consistent than ball!
This shouldn't be. Just like the bumblebee should not be capable of flight...

Have you tried examining the fired patches? .010 patch thickness with Swiss FFFg sounds like a recipe for blown patches. Swiss is a fast-burning powder, then using FFFg is faster yet. So pressures may be building rapidly.

The Pennsylvania has plenty of barrel lenght to achieve good velocity with FFg or even 1.5Fg (you may need to increase the charge, but you can get decent velocities with lower pressure).