sachem longrifle
Noting that you have made less than 30 posts, I'm guessing that your fairly new to the forum.
That said, maybe you haven't read about the sights on your GPR.
The front sight was intentionally made taller than it needs to be.
When you take it out shooting at a target it will be hitting very low. If you crank up the adjustable rear sight (if it has one mounted) it will still be hitting low.
My advice is to crank it up so your shots are on the paper and work on developing a good powder/patch/ball load that groups tightly at 25 yards. Once this load is found, then take a smooth flat file with you to the range.
Shoot a 3 shot target, then file some off of the top of the front sight blade.
At 25 yards range, filing off 1/32 of an inch will raise the point of impact 1 5/16 inches.
Filing off 1/16 of an inch will raise the point of impact 2 5/8 inches.
Continue shooting and filing until you get the group centered. Then move the target to 50 yards and start shooting and filing again.
At 50 yards, filing off 1/32 of an inch from the top of the front sight will raise the group 2 5/8 inches.