FORT A.P. HILL, Va. -- The legendary Marine Lt. Gen. Lewis B. "Chesty" Puller is said to have once stated, "You don't hurt 'em if you don't hit 'em." Marines and Sailors of Battalion Landing Team, 2nd Bn., 2nd Marine Regiment, 26th Marine Expeditionary Unit, have been training here since July 6th with a device that will improve their ability hit their mark.The AVNPVQ-31 Rifle Combat Optic (RCO) combines with an M-16A4 service rifle, M4A1 carbine or M249 Squad Automatic Weapon to become a versatile weapons system that greatly enhances a Marine's ability to put rounds on target, said Sgt. Robert W. Phillips, a squad leader with Combined Anti-Armor Team Platoon, Weapons Company, BLT 2/2.The RCO is composed of an objective lens, an eye piece and a fiber optic collector.Looking into the eye piece, a shooter sees a red chevron shape that remains illuminated in all light levels, including total darkness. Directly below the chevron shape are intersecting vertical and horizontal scales.The two scales allow the RCO to function as both a marksmanship enhancer and a range estimation tool, said Phillips, a native of Beacon Falls, Conn., and a primary marksmanship instructor.A shooter can estimate the distance to a specific target by aligning the scales, marked in incremental measurements, on the target. This allows for precise placement of direct fire rounds as adjustments for distance to a target are not dependent on visual estimation alone.In combat operations supported by indirect fires such as mortars and artillery, range estimation previously required the use of specialized binoculars issued to select Marines. Now, because every member of the BLT has been issued an RCO, the unit's ability to call in artillery and heavy weapons support is greatly enhanced.Despite being a superior marksmanship tool and accurate range finder, the optic is not without its drawbacks, said Phillips."The biggest downfall with the RCO is that to use it to estimate range, you have to point the weapon at the target," he said. "And that's not a good thing if you're trying to estimate the range to a group of friendlies coming up the road."As with any piece of gear, the Marines who will be using it must become familiar with its operation, a process that isn't always easy, said Lance Cpl. Joseph Jasany, a driver with CAAT Plt."It's a pretty neat piece of gear," said the Twinsburg, Ohio, native. "But I'm just more comfortable with my iron sights because they're what I'm used to."The RCO is not a replacement for solid marksmanship principles, cautioned Phillips."Optics are fine and dandy," he said. "But everything can break and, in the end, it all comes down to putting the round on the target."Each component of BLT 2/2 participating in the training here has been to the range to make individual sighting adjustments to the RCOs and get a basic introduction to its use.The battalion first began using the RCO two years ago during Operation Iraqi Freedom II, during which the device was distributed mainly among those with leadership billets and designated marksmen, said Phillips.Currently, every Marine in the unit has signed for or received an RCO.Battalion Landing Team 2/2, an infantry battalion reinforced with a tank platoon, artillery battery and Assault Amphibian Vehicle detachment, is the ground combat element of the 26th MEU which is scheduled to deploy in support of the Global War on Terrorism early in 2007.