HaveBlue tried to use the same lower receiver to make a full-blown .223 AR-15/M16 rifle (Opens in a new window), but it didn't work. Funnily enough, he thinks the off-the-shelf parts are causing ...

The MR556A1 Upper Receiver Kit allows high quality AR-style rifles ... and attaching the HK upper to an AR lower receiver using the ... of the gas tube normally found in AR15/M16/M4 ...

The Army is issuing Soldiers a new small arms 5.56 ammunition magazine designed expressly for the M4/M4A1 carbine and M16 family of weapons. The 2nd Battalion, 75th Ranger Regiment from Joint Base ...

However, the T65 is hardly a clean-slate design, practically copying the M16 design in the lower receiver and heavily emulating other elements in the upper receiver.

The innovative SHRIKE 5.56 upper receiver is designed to fit any MIL-SPEC quality AR-15/M16/M4-type lower receiver and features a dual-feed system, allowing users to configure the SHRIKE 5.56 from ...