By long range, are you talking 100, 200yards, or more in distance? Are you looking for any specific style of rifle, such as the optima or would the other in-lines be acceptable? As for caliber the .45 caliber might give you a flatter shooting advantage, but that means a lighter bullet. The .50 caliber can be loaded down to a .45 caliber bullet. If your looking at shooting powerbelts at extreme ranges then the .45 caliber might be an advantage. There are a lot of factors that come into play. The best thing you can do is look at some of the different rifles out there on the market.

I have a T/C Black Diamond XR (means extended range) it is a long distance shooting rifle. They are on sale for $200.00 and with it you get the T/C warranty and quality. There are also some Knights on sale, and well as CVA's. Nothing wrong with a CVA.