12 bore twist rate

[Blackpowder8bore]

Im getting a 12 bore built with 1 in 66 twist rate. Im meaning to shoot lead projectiles meaning bull or ball.my question is does anyone have experience with such a bore and do they like prb or conical lead bullet?shots are 100 yards

 

[BS]

My 12 bore is .729 with a 1-72 twist.

I shoot 175FF and a heavy patched .725 RB.

Second shot is a Tapered Paper cartridge with a hard .717 RB. [fastest reload found] Hunting.

http://rjrenner.blogspot.com/p/tapered-paper-cartridges.html

 

[excess650]

Modern rifled 12 bores are typically 1-28" to 1-36" for shooting conicals. Forsyth advocated much slower, more like 1-100" to 1-144" for shooting PRBs, BUT his intent was high velocity by way of heavy powder charges.