If it's a long distance to the next target/array you need to lower the gun, and sometimes hold in one hand only, to use your hands to help your body move fast to the next target/array. Then get the gun up while coming into position a couple steps before time to shoot.
Thanks!!!!
I try to keep my gun up walking, running (well my very slow version of running), "shuffling", side stepping, etc...just keep the gun up during the whole stage.