mgray: what kind of balls are you using? with mag, they are size sensitive. if too small, you will get chops and if to large, the balls will get stuck in the feed neck. with the mags, just open it up and re-align everything back up. what remote line you are using?
bheleu02: a longer barrel doesn't mean better accuracy. with the double feeding, it's the problem of the detent. the older detent (metal ball) are better built to stop that. if you are having issues with double feeds, i would recommend in you getting the lok bolt system. that should do a better job.
you can check out my videos on youtube: azntactical. all i do is play with the t68.