All of the G4 series guns use the Combat Machine as the base gun. As far as I know none of them are upgraded internally in any way. For the price, you can do much better on internals. If you plan to upgrade it internally, the externals are very nice.
"Airsoft is a game, and it is a game in which honesty, integrity and honor play a very important role. This is not paintball." -NEASG RulesI make custom Kydex gear. See some of my work HERE or email granitestateguns(at)gmail.com
Follow my blog HERE