Right now I'm shooting the Hornady Leverevolution 325gr. That's about all my dealer had for ammo . Thinking about trying some Winchester hollow points . I had some bad luck years ago shooting Hornady muzzleloader bullets, no blood trail witch is why I shoot Barnes bullets in my muzzleloader now.I average 1 MOA with my 45-70 but I am shooting it the way it was designed to be shot. Heavy 500ish gr bullets with Black Powder. I am shooting an 1874 Sharps copy with Vernier sight.
The CVA scout in 45-70 is a hunting rifle not a shoot little bitty groups target rifle. If you are shooting 1 1/2" and under groups at 100 yards with factory ammo then I would hang on to it. Where you need to be concerned is learning how much drop you will experience. Depending on bullet and velocity you will average between 3 and 6 inches drop between 50 and 100 yards and will experience about the same between 100 and 150 then again between 150 and 200 yards. I am running a 518 gr bullet at 1150 fps and drop is 6 inches between 50 and 100 yards and a foot between 100 and 200 yards. You really need to know precisely the yardage and your drop past 150 yards. Great thing about the 45-70 is you will never be under gunned for anything in North America with the proper bullet and load and if you line two of what you are shooting at side by side you can get two for the price of one bullet. LOL A freight train don't have to be moving fast to run through a bunch of stuff. You did not mention which Hornady ammo you are shooting but the Hornady and Sierra 300 gr HP bullet is a good deer size game bullet. The Hornady 350 soft nose is a tougher bullet than the HPs. The old Remington and Speer 405 soft points are good one bullet do everything bullets.