I have dropped the gun with the hicap in it and, sure enough, the tab snapped off. I did also encounter feeding problems, and I noticed that it would feed if i applied upward pressure so i decided to put a little epoxy on the mag right where it meets the mag release, and it fed fine even thought it was a bit tough to get in.
I have chronoed it at 330-335fps with excels, and about 325-330fps with A.E. blacks, I say that because the elites were rumored to be more powerful(they did a study on airsoftmechanics.com)
I did not encounter any rust on the gun when I received it although the selector switch, and bolt cover did eventually accumulate a bunch of small dots, all I did was wipe the cover, and switch down and I havent had any problems since then
P.S. How did you get your flashider off? there is a small tab (you can see it in your picture) that is at the base of the front sights and it blocks the flashider from coming off