I have a new SD9VE with the following issues and was wondering if anyone had similar experiences.

I am not a new shooter. And do not have these issues with other weapons I have used. I like the feel and ergonomics of the weapon and it is reasonably accurate out of the box.

Slide does not lock back most of the time.
Frequent failure to feed.

The weapon has been cleaned and lubricated well.
It does not seem to be magazine or ammo related.

Round count between 200 and 300.

Four stock 10 round mags. (Mags are still a bit tight but have been sitting fully charged for a week or two.)

Factory Ammo. Federal,Remington and Winchester.

Any thoughts on possible causes and solutions.

Thanks