i had a dboys m4 for 1 game and it locked up... nothing some internal work cant fix but unless you know how to fix a gear box you will have to pay someone to do it. get a gun that is fundamentally sound and dont worry about the fps and that shit, or even full metal bodies, they are very realistic but are not worth getting a d boys over a combat machine. like i said look at G&G, CA and other high quality guns.