so i have this http://www.airsoftgi.com/product_info.p ... ts_id=6985
and i was putting this on http://www.airsoftgi.com/product_info.p ... ts_id=3707
but i hit a problem, i dont know much about metal bodys but on my plastic reciever this nut for the rail fit nicely. this dosent want to let me screw it all the way.