[Ratters]

Some brand new pistols have casting "flashings" on the frame (usually the lower) that can be skimmed over and knocked down flat with a fine flat file. If there's any up and down slop in the slide with the mag out see if the slide pushes up when the mag is inserted.

Also see if the piston in the slide is free moving when you apply some push pressure on it.

If you can remove the piston check the casting of the slide where the piston lives and see if there's metal flashing or debris that might be snagging on or hanging up the piston from freely travelling when the inserted mag pressure is against it.

Sometimes the metal in the blowback housing can wear from the hammer digging in or gouging it's own path and this can also cause drag or hangups so make sure this is also lubed.

I would also consider checking the piston seal to make sure you are getting good gas efficiency or lots of blowby if it's lots of blowby then I'd swap the seal. Chronoing the pistol or doing the bottom of a pop can test should indicate approx per shot velocities. Generally speaking it's one, two or third shot punch thru depending on the pistol make, model and gas used.

And finally, if it's still under warranty get yurself another one