GC_UPC M4E1 ASSEMBLED UPPER RECEIVER 10.5'' 5.56MM CARBINE LENGTH MAP APAR640221M2 show more like this 14.95 TheGunDock.com GC_UPC M4E1 ASSEMBLED UPPER RECEIVER 10.5'' 5.56MM CARBINE LENGTH MAP APAR640221M2 show more like this Free shipping over $400 (Excludes Ammo) Gman Sport GC_UPC Aero Precision M4e1 Assembled Upper Receiver 10.5" 5.56mm Carbine Length - M4e1 Assembled Gen2 Upper 10.5 Car Length 9 Handguard $534.99 APAR640221M2 show more like this additional Brownells GC_UPC M4e1 Assembled Upper Receiver 10.5'' 5.56Mm Carbine Length 100025505 $538.13 100025505 show more like this Firearms $18.45, Free over $500 Shooting Surplus