Having had great success with a 50-70 duplex load that consisted of 60 FFg/5 SR4759 in both my Shiloh carbine and Military Rifle, I loaded up a batch with 5 more grs FFg and the 5 grs 4759. More is better, right? Wrong!
It required more compression (yes, I use a compression die), and that distorted the cases to where one brand would not chamber in the current-made carbine. The chamber of the MR accepts anything I feed it.
Recoil was definitely more noticeable, and it was very clean burning, but accuracy in both dropped dramatically. I'm going back to my original load. Hot rodding a 50-70 doesn't work.