A Proline Armalite M4 with the massive looking yet remarkable lightweight S.I.R. system fully licensed by A.R.M.S. Made famous by US special forces, the S.I.R. system was one of the very first free float rail systems that allows a customized set-up of tactical accessories. On this Airsoft gun the SIR (Selective Integrated Rail) allows super easy access to the battery compartment in the front.

Features:

• Proline
• Metal hop-up chamber
• Spring guide with ball bearing
• 8mm double bushings
• Chrome mock gas tube
• Rear ARMS flip up sight contoured to fit rail system
• Easy battery compartment access
• Front grip included
• Removable side rail sections
• Functional bolt catch release
• LMT sopmod stock
• Raised rail brings up the optical sights better when wearing a mask.
• 122 m/s / 400 fps
• 350 high cap metal magazine
• Metal body, stock tube barrel, front sight and rails