Taurus G3 slide lock issues

[357smallbore]

Brand new out the box today shooting of my Taurus G3. Highly disappointed. Slide won't stay open after last round. Wouldn't go on battery a few times when firing. Had to smack slide to close and then it'd fire.
My G3C does not have these issues.
When shooting at the bullseye from 7yrds I am aiming dead center and the rounds are hitting 3 inches low. When I aim higher they hit where they are supposed to go.
Gonna give it another 200 rds and see if it improves.

 

[5-SHOTS]

First of all I would try to shoot the pistol with one hand, taking care that the thumb is down to avoid any possible contact with the slide stop. If the problem persists, I would try to disassembly the pistol, insert the empty magazine in the frame and check that the magazine follower is pushing the slide stop up correctly; check this with both magazines. If these things don't work, I would contact Taurus customer service.