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 ...

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 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 ...