Sentence:  Shafter was also deficient in field artillery, the arm traditionally used to "soften up" defensive positions before an assault. This weakness was partially remedied on 1 July by a <WSD>well-handed</WSD> battery of rapid-fire Gatling guns, the first significant use of such weapons by the United States Army. 
Meaning of the word marked with <WSD> tags:  Having plenty of support.