The US Marines will begin replacing their old M198 towed 155mm howitzers with new M777 lightweight towed 155mm howitzers in 2002. The changes will be dramatic. The new M777 can be carried by the CH53D helicopter and the MV22 aircraft, giving more options to get the guns on shore. The M198 can only be carried by the few CH53Es. Because the lighter gun is easier to handle, it will take only 3 minutes to prepare to fire (from the time the truck stops) compared to 12 minutes for the M198. It can pack up and move in less than 2 minutes, compared to about 4 minutes for the M198. The M777 can change firing directions to engage an "out of traverse" target in under 3 minutes, compared to 8 minutes for the M198. The M777 is fitted with night vision scopes for direct fire, improving its ability to defend itself against an armored attack. The M777 will be coupled with the Medium Tactical Vehicle Replacement, basically an existing five-ton truck rebuilt with a new suspension, larger tires, and a central tire pressure regulator. The MTVR can carry more ammunition (136 shells vs 96 for the five-ton) at faster speeds (30mph off road compared to 20mph for the five-ton). --Stephen V Cole