I could be wrong, but my understanding was he basically turned and fired and shot everyone, starting with the folks there and then shot the backup when they arrived. There wasn't any "hunting" involved to my knowledge. He was a well trained shot, whether or not he had much hunting experience. His behavior seems particularly strange given he was a naturalized citizen and served in the Guard for several years. He was obviously acclimated and well familiar with America.
They were spread out over a 100 yard area.
http://www.freerepublic.com/focus/f-news/1286030/posts
According to court records, Vang allegedly shot several of Sunday’s victims in the back.
Hard to shoot someone in the back when they are in front of you. You would have to circle behind them. Add in the fact that he turned his jacket from orange to cameo and he was hunting.