got 50 cal kentucky. Shooting 70 gr FFFG pryrodex -(want to burn it up and change to 2F pyro-) and RB patched. shot over pond and seems max yards only about 100- 125 yds! no adjustable rear sight but I held hi and hoped could reach 200 yds max. still dropped like a rock!
Is that max effective range RB shoot? Could it shoot higher if i grinded 1/8" front sight?
Where can i get adjustable calibrated rear sight to max at 150- 200 yds - also brand and price?Thanks!

On a 50 cal tradional rifle like the kentucky rifle, 100 yards is doin pretty well.

Are you target shooting or hunting?
A PRB runs out of energy quickly. I'd keep hunting shots under 100 yards with a .490/.495 ball.
If the sights are not adjustable I'd pick a load and check it carefully for accuracy before I got in a hurry to take a file to the front sight. That's the way to raise POI, but once you take it off, you can't put it back if you change your load.

125 yards max with a .50 and a PRB. With so little powder, i'd stay within 100 yards.

For target practice 200 yards is fine, However, dont expect to get good groupings. My traditions .50 kentucky flintlock with 110 grains FFFg and a PRB will do 2" groups @ 100 yards which is pretty good with the patches burning up like they do

Use a .490 roundball with .018 pillow ticking patches and you can use a heavier charge.
Also, if you want an adjustable rear sight, go here and order one. The CVA mountain rifle rear sight is adjustable and will fit the spanish made muzzleloaders. 3/8" dovetail i believe.
www.cainsoutdoor.com