I WOULD NOT USE BULLSEYE IN A RIFLE. It is designed for small capacity pistol cases ie. 45 ACP. It would be very easy to double or triple charge a rifle case with Bullseye thereby creating a very deadly pipe bomb. You wouldn't drive a slingshot dragster to the grocery store.
Yes, it would be VERY easy to double or even triple charge a 45-70 case with Bullseye, but not if you're careful and watch what you're doing. That means no T.V. or other distractions. And I am one of the guys here who uses the data from Lever Gun Performance Studies. It's a site entirely devoted to the use of various pistol powders in rifle cartridges. I've been using 2400 in my 45-70, and have had no trouble at all. Like I said, BE CAREFUL.
Following the Lever Gun data referenced above, I have had a very enjoyable time with 11 gr of Bullseye under a 350 gr Dardas flat point bullet. Economical, clean, enough recoil to be satisfying, very nice groups... and powerful enough to take deer within 100 yards if necessary. For my plinking loads i prefer Unique, but really... what's not to love?