Okie Dokie...
First check your patches. IF you're damaging the patches during loading the ball will seem to flight straight out to 40-50 yards, then downright disappear while flying beyond 50 to 100 yards.
NEXT, you need to buy an inexpensive spotting scope, IF you want to go to 100 yards.
THEN, try 60, 70, and 80 grain loads of 3Fg at 50 yards, and determine which is most accurate. So you shoot three shots and see if any of the groupings are obviously closer together. This is done from a bench using a rest. Repeat with 2Fg just to be thorough. Confirm this load with five shots, very meticulously loaded, with meticulous cleaning between each shot.
After you have the most accurate loading, THEN you work on going beyond 50 yards. The next step is to try 75 yards, and you will need a spotting scope for this. Check your grouping, but don't worry about hitting the center of the target..., yet. See if your group is drifting left or right. You may tap your rear sight slightly to adjust for right or left, but don't worry about elevation..., yet. Then go to 100 yards, and repeat.
Once you're centered the group (but likely low) at 100 yards, you may try adding 10 grains of powder to see if there is much rise in point of impact..., but more than likely you will need to file down the front sight post a tad. Use masking tape on your barrel behind the front sight and in front of the front sight three layers in each location before you file, to protect the barrel. Then gently remove steel or silver from the front sight post by filing lengthwise. After a little is removed, test fire the rifle to check the impact. It should have moved upwards.
Repeat the filing and test firing process until you get the ball near the bullseye. Then shoot a three round string of fire to confirm.
NOW IF you find that group is on the target but kinda large at 100 yards, it may simply be that your front sight is too dang thick. I've seen 'em where it was like trying to center a quarter on the top of a 2x4 piece of lumber. IF the front sight is too thick you get a thin, silver front sight blade from Track of the Wolf.
LD