The H&K G11 was designed to change military rifles forever with its futuristic technology—but why was it never adopted?

For illustrative purposes. (Janes/ Amael Kotlarski) Heckler & Koch (H&K) is currently developing a 5.56×45 mm version of the HK421 light machine gun (LMG), which is currently chambered in 7.62× ...

It works with the M4 Carbine, the M249 machine gun, and the H&K and M16A2 rifles. It is suitable for use in most weapons with a 1-in-7 barrel twist. The M855A1 has a copper-jacketed steel core ...