It would be nice if you mentioned a price range. Since you want to mount a scope on it, then an inline would be the way to go.

That Encore that Doegirl mentioned is a great rifle. They will shoot a sabot with extreme accuracy. They can shoot loose or pellets. They have a 150 grain max load in the event you need extra power for something really big, or extreme ranges. Plus there is the bonus with them of changing out barrels to modern center fire rifle barrels.

Some other rifles to look at would be the Omega, Triumph, Knight has a rolling block that came out, and a forum member has one. I have been waiting for him to shoot it and review the rifle for us as it interests me as well. Knight also has a rifle KP-1 that is their answer to the Triumph. I do not think they have hit the market just yet.

Also on some of the auction sites, there are good used rifles. Long Range Hunter, Disc Rifles, Wolverines, Bighorns, Black Diamonds, Omega, NEF Sidekick, and BPI makes some excellent shooters as well. The Apex, Optima, Kodiak, X-150.. again, there are lots of different rifles out there. All of them would probably do you good.

Since you are limited to no scope, you are at the same advantage we are.. you can shoot as far as you can see. If you wanted to really stretch that, then you need to get a rifle that will shoot flat. I would still though go with a .50 caliber over the .45 just because of possible future hunts you might take and for other reasons.