TaxPhd hit the nail on the head. Something around a 1:28 twist is designed for shooting conical bullets/Maxi-Balls and sabots. The 1:66 twist is generally considered THE twist for round balls. The 1:48 twist is a comprimise so that you can shoot either with decent results. It usually doesn't knock your socks off with either, but it is perfectly adequate for hunting accuracy at black powder ranges. If you decide that you are going to exclusively shoot one or the other, down the road you might want to get a new barrel with a twist designed to optimize that load. I pretty much use my black powder rifles for hunting, and I think the heavy bullets are the way to go for hunting. I bought my new barrel before a bull elk hunt since I wanted to shoot the heviest bullet I could for max penetration. Unfortunatly I found that it would not stablize the 460 grain bullets I was trying to shoot. It would drive tacks at 25 yards, I would move back to 50 and couldnt' keep it on paper. I gradually started at 25 and moved back and at about 40 yards, things fell apart. I tried the lighter 370s (or whatever they are) and they were mucho accurate. About as well as I can shoot with iron sights at 100 yards. Plenty of game has been taken for many years with round balls and I think they are fine for whitetail deer. You will get higher velocity and a flatter shooting load with round balls (as opposed to bullets, sabots are of course higher velocity yet and flatter yet). I just decided to stick with the maxis since I occasionally apply for elk and I would rather just stick to one thing. Black Powder is a heck of a lot of fun. I always wish I spent more time shooting my BP guns. It just takes so much gear and time to do it. One bad rap that BP guns have that I think is crap is cleaning. Using boiling water, I can clean my muzzle loaders a heck of a lot faster than I can my conventional rifles. Once you boil the water, the barrel is clean in a minute or two. I then do it again with clean water and lube the heck out of the barrel. One other pointer that has worked for me; try out T/C Bore Butter as a lube. I found it to be everything they say it is. It allows you to fire a lot more rounds before swabbing out the bore, and cleans up real easy. That was one of the greatest things I found in my black powder shooting career. I have a muzzle loader just for whitetail hunting; a Remington 700ML with a Burris 2-8 scope. In that rifle I shoot pyrodex pellets and sabots. A lot of Western states don't allow scopes during ML seasons and some don't allow sabots or pellets. So, I use my T/Cs for out west. I come from Ohio and still go back every couple years to hunt whitetails on my parent's property. There, as far as I can tell, you can use any ML you want. I haven't hunted with it yet since I missed last years hunt, but I intend to try it out this year. My experience is that the in-line is a real pain to clean. On mine it blows fouling all over the scope and scope mounts. And fouling gets inside the bolt. I shot it a couple times without disassembling the bolt and had corrosion. Luckily I have a stainless gun and after I cleaned it up, there is just discoloration, but I wouldn't buy another one.