Hi rebAL;
I have a T/C New Englander in 50 caliber. It is the most accurate ML rifle I own. Sadly, this even includes a PC Longrifle that I painstakingly built year before last!
Anyway, I have several suggestions for you.
First, the sight picture. The front sight bead is large. You may be covering the target with it? Personally, I set the round front sight into the round groove of the rear sight. Then I figure for the ball to impact at the top, center, "12 o'clock", position of the front sight. It makes for a "finer" sight picture, plus it would be a quick way for you to impact lower. Using this sight picture, I routinely shoot 2" groups at 60 yards, and my eyes (along with the rest of me), are 53 years old.
Second, a more lubricated patch will strike higher, a less slippery patch will strike lower. You might work with the patch lubricity. This is of course, "fine tuning", and you probably have a situation that goes well beyond this... however, it's something that you should know.
Third, call T/C. Their service department and attitude is second to none. If you explain your problem to them, my money's bet is that they will probably just ship you a new, higher front sight. (It's that the wrong front sight height might have been installed on your rifle at the factory.) If you measure the height of your front sight and email me, I'll measure mine and let you know how they compare. My home email is sally@lcsys.net.
Regards,
Jerry.
Third,