I've always used a plastic gun with a fixed nozzle that creates the larger drops for my turf applications and a metal one with an adjustable nozzle only for plants because that's what Lesco recommended. I noticed my tech guy using the metal one today and when I asked him why he said he liked the coverage it gave better than the plastic one. He's applying the correct amount per sqft. Is there a reason why the plastic one should be used over the metal one on turf? BTW I'm applying 3way, Pre-M and liquid fert.