January 6, 2020 Please wait. document.cookie = "__adblocker=; expires=Thu, 01 Jan 1970 00:00:00 GMT; path=/"; } Download the model according to the specified sizing parameters in either 3D or 2D format. Check with a square or dial indicator. Valid email address is required to complete registration. function async_load(){ quick mix mike 07-07-2011 02:45:30 ZULU, Right-hand twist, 6 grooves, 1 turn in 12 inches, Colt Manufacturing, Harrington and Richardson, Hydra-Matic Division of General Motors. Hopefully, someone knows. An AR15 Lower Receiver on top, with an M16 lower on bottom. Do you have a better or corrected version of this model. The XM16E1 lower receiver is a replica of the receiver on the original XM16E1 rifles developed for the U.S. Army in the 1960s. January 12, 2020 $69.99. The market share was largely owned by Colt and their SP-1 version of the AR. Configuring model for download. M16 Lower Parts Kit. December 16, 2018 //