Artillery: Lightweight Howitzer Joins the U.S. Army


February1, 2007: The U.S. Army has received its first M777A1 lightweight 155mm howitzers. Eventually, the army will receive 273 of these guns, at a cost of $1.7 million each. The British designed howitzer is also used by Canada, Britain and the U.S. Marine Corps (which is getting 377 of them). The army will use them in airborne and Stryker brigades. A five ton truck is used to tow the guns, but a special, 4.5 ton LWPM (Lightweight Prime Mover) is being built to do that as well. The five ton M777A1 is 40 percent lighter than the weapon it replaces, the M198. This is because the M777A1 makes extensive use of titanium, and new design techniques. It fires shells with a maximum range of 40 kilometers (using RAP, or rocket assisted projectile, ammo). A crew of five operates the gun, which can be ready to fire in under three minutes, and ready to move in under two minutes. The M777A1 is light enough to be moved (via a sling) by CH-53E and CH-47D helicopters. It's sustained rate of fire is two rounds a minute, with four rounds a minute for short periods. What will really make this gun useful is the new GPS guided Excalibur shell, which is entering service later this year. Otherwise, it fires unguided shells that land anywhere within a 200 meter circle. That's at 25 kilometers range. Accuracy gets worse at longer ranges. But not with the Excalibur shell, which falls within a ten meter circle (the middle of that circle being the "aim point") at any range. The Excalibur shell is essential, because ten 155mm shells (of any type, with their propellant and packaging) weigh about a ton. Ammo supply has always been a major problem with artillery, and Excalibur is the solution.