Nifty XM177 Gas Blowback rifle under the Viper Tech brand which gets its same pedigree from Inokatsu, which also means a pricey pedigree as it's available at eHobby Asia for US$650.00 and you can use WA M4 GBB magazines with it too... "Extremely robust VIPER AR-15 Series Gas Blow Back - 2010 VERSION! Viper is OEM factory of Inokatsu M4 GBBR to provide same level supreme craftsmanship & Top Notch finishing. As solid & robust gun as a real steel.

Features:

• High Quality CNC Machined Forged Aluminum Receiver
• Real M16A1 Type Body (without marking)
• M16A2 Type Carry Handle
• 9.5inch XM177 One-Piece Outer Barrel
• XM177E2 Type Steel Flash Hider
• Functional STEEL Bolt Carrier
• Full Size Solid Fixed Stock

1. Includes 50 Rounds Gas Operated Metal Magazine (We recommend to use with ProWin / WA / G&P Gas Operated Magazine 'SOLD SEPARATELY' to operate the best performance of this lovely baby)
2. You can even take RED GAS on it to enjoy the True Recoil (VIPER TECH suggested no more than 12kg power gas)
3. Real Measurement 14mm Clockwise barrel extension tube
4. Sling mount can be installed with single, 2- or 3- point tactical sling"