I do not have a rifled, breech loading bore gun at the present but was considering re-barreling a 20 ga. Remington rolling block action with a 20 ga rifled barrel. The action is in great shape but sadly someone cut the barrel back to 18 inched years ago. What is the twist on your bore guns? I am going to ream and rifle a 1 1/8 octagon barrel blank and install it on this action. I have not ruled out the possibility of a faster twist shooting a slug either. All options are open, I am fine tuning the rifling bench, and have ordered the barrel blank....