http://www.dnrsports.com/acatalog/Lyman_Muzzleloaders.html
I bought my rifle from D&R Sports.Com a couple years back. I bought the Lyman Trade Rifle .54 caliber Flintlock. You can change the barrel over to a Green Mountain Barrel with a 1-70 twist I believe. I would have to double check though. I lost my charts somewhere. They also make a 1-28 twist if you want to shoot conicals or sabots.
The 1-48 twist that comes with the rifle does an excellent job. 90 grains of Goex 2f and a .530 patched roundball and I got a very good shooting rifle. At 50 yards that load will shoot length way through an entire deer, breaking neck, brisket, and finally a rear leg. It has power. It also shoots powerbelts in the 405 grain weight and maxiball excellent. $279 is a pretty good price. D&R Sports are cheaper but I no longer recommend them as a store. I refuse to do business with them. I do not think you would have problems with them, but just watch your paper work real close, and anything promised, get it in writing. And that's all I have to say about that.
The rifle has excellent wood, comes with traditional and buckhorn sights, and a wooden ramrod. If you order the percussion model, get a new stainless steel nipple for it. The one that comes with the rifle lack a little. If the rifle acts up, that is the first place to look. Also the stock is not sealed as you have the option of making it darker or simply waxing it to seal it. Also the traditional rifles are very easy to maintain. With the hooked breech design of the Trade Rifle, you remove the barrel and give the rifle a hot soap and water bath and it comes clean very easy. I would recommend this rifle to anyone. If you are limited in experience with traditional rifles, you might want to get a percussion cap model. If you want real adventure and a learning experience, get the flintlock.