25 yards is a LONG distance to start with dude! Me thinks U expect too much It sounds like U have shot a gun before, but are not a regular shooter.
Start at 15 feet, and then work your way out to 21 feet.
Quite often, it takes time to get the hang of a new gun.
It took me 1000 rounds to stop shooting low with my HK USPc, and I did not have this problem with a fullsize HK I used to have (or any of my other guns). I benched the gun on sandbags, though, and I could tell the gun shot fine. I just had to get used to it.
Don't give up now. But, unless you are a super experienced shooter - to start at 25 yards with a new gun is unrealistic.