The CVA caplock does indeed shoot very nicely.
I edited the original post to note the flinter appears to be a CVA kit too, from the mid-70's.
Soon as I get the patch/lube combination down we'll see just how well the .50 does, but so far it looks good.
Bore looked horrible, but after Kriol and brushing and 4o steel wool and Kroil and patches and pressure and sweat...
Relieved the edges at the muzzle as per your thumb and abrasive cloth method - loads nicely and rams smooth too.

I just got in from the shop where I gave the little .45 flint barrel the same treatment. It is starting to take shape as well. It has a similarly slow twist as the CVA too, which I find pleasing.

Cheers
Tinker