Some great suggestions from JCR TX and sprchng, you have not stated what version your Legend is, so i will say this, if your Legend is 1.11 version run it wide open meaning set the IF to 0 and sensitivity as high as the ground will allow you, run in Field Mode, A (All Metal) pattern or G (Ground OFF) Pattern do not discriminate anything, ground balance over ground you know is void of any metal objects and frequency shift, if you are getting a machine gun tones increase your recovery speed you will loose a little depth, increasing the recovery speed has helped me when I am getting into heavy iron particles in the ground when detecting for gold nuggets, the Legend seems to like a faily quick swing speed but I am an advocate of slow swing speed other than what I have stated have fun