While I think that the entire manned vehicle portion of the Future Combat System is a waste^*, there are some technologies that look to be interesting from a military perspective.

Case in point, the lightweight XM360 120mm gun for the MCS (Tank) variant of the FCS-MGV^†.

It’s about a ton lighter than the 120mm gun used on the Abrams, with significant reductions in recoil, both due to a more effective recoil system, and because it uses a muzzle break that is compatible with sabot rounds.

It achieves the weight savings through a high strength steel barrell with a composite wrapping to keep tension on the barrel, and by using largely titanium components in the recoil assembly, much like the lightweight towed M777 155mm howitzer.

Of interest, the gun is also capable of indirect fire out to 12 km, which would be an improvement on M256 used on the Abrams, which does not have this capability.

Image courtesy of Wiki.

^*Full disclosure, I worked on the Future Recovery and Maintenance Vehicle, FRMV, “wrecker” variant from 2003-2006 at United Defense (later BAE Systems after the Carlyle Group sold me to buy Dunkin Donuts).
^†Future Combat Systems-Manned Ground Vehicle. These are the ones that are the tanks and APCs. As opposed to the various unnmanned vehicles, etc. that form the full FCS.