shooter problems nothing but net

please help, ive been having problems with my shooter. I have the standard ratio for the shooter and encoders on the axles where my wheel for the shooter is, and i have it set to a be a specific rpm no matter what battery power, but whenever i launch balls (all balls in testing same softness (all were hard)), they will end up in different places every time. my lift is a vertical pick up, which then lets the ball roll out onto a small ramp (about 6.5") and then into the shooter, at a 45 degree angle. there is a curved pice of flatbar over the rollers where the ball would come off the rollers to eliminate the different variables of momentum.

How much do the places where the ball ends up vary?
It might be helpful to post some pictures

i cant post pictures atm, currently in class, wont have access to the robot for another 3 hours, but it ranges by about a foot above and below

Gearing the two sides together will help with horizontal accuracy, but sounds like your problem is more vertical consistency. What velocity control are you using? Can you tell us more about your thrower? Gearing motors etc.

Not that this will apply to you but if your compression is super high it will make the system very sensitive to even the smallest of compression rate differences. Also, if you have a wireless programming cable, run you system with a debug stream and make sure that your actually returning to the same speed after each shot.

what type of shooter do you have, 2 wheel, 1 wheel?