When Western Arms introduced the first M4A1 Gas Blowback Rifle in 2008, they set the standard in gas blowback rifle developement with several airsoft manufacturers adopting their design for their own M4 GBB-R line-up. When it was first introduced the receiver was made of plastic but according to Hyperdouraku, they have recently adopted a metal receiver for better quality. This review is about the  COLT M4A1 American Sniper Custom Series so find out what other improvements they made for this GBB-R.

Read the full review here.