The .50BMG bullet is huge. It's huge enough that researchers have been able to work all kinds of technologies into them such as RDX explosives. DARPA has recently upped the ante with what they call the EXACTO (Extreme Accuracy Tasked Ordnance) guided .50BMG bullet!! The round is modified as a 4" projectile with an optical sensor on the nose, guidance circuits, in-flight adjustment controls and power to effectively let snipers routinely hit targets over a mile away with greater ease. Imagine the future ... laser guided, armor penetrating, RDX filled .50BMG rounds for "hunting" and "alien invasion disaster prep."