what size group are you getting at 100 yards with open sights. I'm shooting at a piece of cardboard about 18"x12", and i'm hitting it everytime but it's all over the place. I know some of the problem are the sights. Maybe a ghost ring rear sight would help.
I shoot a .50 caliber Lyman Great Plains Rifle. With the original 1:60 patched roundball barrel, firing a .490 Hornady swadged ball in conjuction with a .015 pillow ticking patch over a volumetric 70 grain charge of Pyrodex P, it'll shoot clover leafs for three shots at 100 yards. It is a very accurate caplock. With the 1:32 conical barrel, it'll shoot within 2 M.O.A. for three shots at 100 yards firing Hornady Great Plains bullets over 70 grains of FFg Triple 7, provided that my loading technique is consistant and I seat the bullet to just ever so slightly compress the powder -and I do mean "ever so slightly" as in virtually not at all. With the same charge of Pyrodex RS, groups open up to 3" or more at 100 yards for three consecutive shots, with significant vertical stringing on the target, indicating a velocity variation. With real FFg Goex, it'll put three shots in under 2.5 inches at 100, pretty much regardless of temperature or humidity, and within reason, pretty much regardless of how sloppy and inconsistant my loading technique is. It isn't the most accurate powder, but it is the most consistant.
My sights are the fixed "primitive" rear and a custom German silver front blade. Nothin' fancy there.
Whether balls or conicals, it remains a 125 yard max range rifle. The difference is use. I use the patched balls for whitetails here at home and the plan is to use the conicals for elk, assuming I draw a tag somewhere this year.
I'm not convinced that a modern inline is really going to offer me much of an advantage, aside from being easier to shoot in low light and easier to shoot accurately, period, assuming its scoped. I haven't seen any that are significantly more precise than my GPR, however.
-JP