If your going to shoot any real long range for fun, then your going to have to spend some money on the better bullets. If you just want to sit in the yard at 25, 35, 50, 75 yards and shoot cans or punch holes, then there are a lot of bullets that will do the trick.
Black Jack Shooters Bill and Judy make a number of different bullets that shoot great out of my inlines. They make a LEE 200 grain SWC .451 diameter that in a black harvester sabot will shoot amazing groups. You could actually hunt with this pure lead bullet but I target shoot with it. You might also want to try some of the 320 grain R.E.A.L. conicals. Lube them with some borebutter or even Crisco shortening and they shoot very well with 80 grains of FFg out of my rifles. The true .50 caliber conical is a great hunting load for short ranges out to 100 yards. I have never shot them further. Send Bill an email... he is great to work with and will help you any way he can.
I had terrible luck with his 230 grain bullet. No accuracy what so ever, and his big 533 grain conical is according to your manual too large for you to shoot. Although they do shoot good out of my other inlines with 80 grains of powder.....
Have fun with your rifle and happy plinking...