175-mm M107 self-propelled gun

The 175-mm M107 was the largest self-propelled gun (as opposed to howitzer) to be adopted by the U.S. Army. The M113 gun has a barrel that is 60 calibers long (i.e., a length 60 times the diameter) -- the highest of any mobile artillery piece ever deployed in significant numbers.

The M107 shares a common chassis with the 203-mm M110 self-propelled howitzer and the M578 armored recovery vehicle.

The vehicle is dominated by the M113 gun's long, slender barrel extending well forward...