I've done quite a bit of target shooting in my life. The thicker the barrel, the less it matters where you put the front on the rest, but it does matter still, a little. During recoil lots of things happen. The gun goes back and up, the barrel can oscillate, your rest can become a fulcrum, and more. The best accuracy is consistency with all those things. Down to when you breathe, and how your heart is beating even.
With this flintlock, I just need a little more steadiness than when I'm holding it. I KNOW I'm not following through enough, I call my shots. So I want to see more what it's capable of. Not get the best precision possible from it, I just want to make sure my loads are shooting pretty good groups. Right now, I'm all over the place. In BPCR I shot AAA class, and I got Expert Rifle and Expert Pistol medals in the Navy, etc. I know what I'm doing shooting, just not with a super long, super slow flintlock!