It has a 45° sear, which is made of pot metal. Plus it comes in at 450ish FPS, which isn't good for that kind of locking mechanism.
Moreover, the piston is plastic, but it's not AA T-10 quality, it's made of some cheapy plastic and doesn't last very long even at 1J.
Unfortunately it's the theme of these VSR clones (even the TM one has 45° sears and plastic piston, but it clocks in at 0.8J and the quality/tolerances are miles ahead).
I'd send it back and swap it for a better gun, the A&K M24 comes with 90° steel sears and it'll last much longer, on top of giving a smoother action of the bolt.