Hogue OverMolded Rifle Length Free Float Forend for AR-15/M16

Determining the length of your gas system: measure the distance from the rear of the gas block to the front of the receiver. If it is approximately 12 ½” it is a rifle length system, if it is approximately 9” it is a Midlength and 7” for a Carbine length. .308 Rifles: There are two basic types of 308 "size" AR rifles, often referred to as DPMS or Armalite "compatible" rifles. The parts, magazines etc do not interchange. For an easy way to differentiate between the two styles of rifles, look at the rear bottom of the upper receiver. A DPMS compatible rifle has a rounded edge while an Armalite has an angled edge. We offer a coupler nut for both types. DPMS #15060 with a 1 7/16"-16 TPI and Armalite #15061 with a 1 7/16"-18 TPI.