FORT JACKSON, S.C. -- Soldiers on Fort Jackson began training with a new weapons system that can launch grenades while attached to an M4 carbine rifle, or be fired independently.A training team was on hand at Fort Jackson Tuesday and Wednesday to familiarize drill sergeants with the newest grenade launcher in the Army arsenal -- the M320A1 grenade launcher, which is replacing the venerable M203. Unlike the M203, the M320 has a removable stock that can be attached to allow it to be fired as its own weapon."With the M203, [the launcher] has to stay with the weapon," explained Alex Mariblanca, a weapons equipment trainer with Tank Automotive Command out of Warren, Michigan, who was on Fort Jackson schooling drill sergeants and unit cadre on the working of the M320.For Sgt. Keala Burks, a drill sergeant in Alpha Company, 3rd Battalion, 60th Infantry Regiment, shooting a grenade launcher isn't something she gets to do every day."We shoot [grenade launchers] in school, and out here when we are out with the privates we might fire a few rounds," said Burks, a preventative maintenance specialist. "Usually, they give us five rounds a piece, but here they gave us around 30."After a while it got heavy, she said. The M320 model weighs five pounds, two more than the model it is replacing.The additional weight comes from the M320's much more durable barrel, which is meant to give the weapon a longer lifespan. Rounds fired through a lighter barrel can deteriorate accuracy much quickly they would deteriorate the accuracy of a heavier one."A lot of the Soldiers that I ask say they prefer to fire this one," Mariblanca said. "This one is easier to fire even in the stand-alone mode."Soldiers also preferred how the weapon is loaded. While the M203 was loaded by pushing the barrel forward, the M320's breach swings open with the press of a button to allow loading from the side."You just push a button and it pops out the side," Burks said. "I think it makes it easier to fire. The problem with the [M203] is that I can't hardly get it open or shut all the way. So I think this one is easier. It's just a little heavier with the material it's made out of."Another difference between the two models: a Soldier fires the M320 while grasping a pistol grip, whereas a Soldier fires the M203 while grasping the magazine.Burks acknowledged that firing the M320 while it was attached to her rifle was difficult because it required her to fire the launcher using her left hand while holding the M4's pistol grip with her right.David Beesley, another trainer from TACOM, noted that the Soldiers preferred firing the M320 without it being attached to their rifles."From the feedback I've seen, I think Soldiers prefer the newer weapon because it can be placed in a stand-alone mode," Beesley said. "Think about it ... If you're carrying an M203 you have to have it with you [on your weapon]. With this, you can put it in stand-alone mode."Say you are in a [mine resistant ambush protected vehicle], you can put it in the turret, and the guy up there can engage bad guys 400 meters away."