The M6 isn't programmable, but it's hot on quarters. With practice you'll learn where to set the sensitivity and discrimination. I used it with sens at 80 to 90 (as high as it will go to keep it stable, just around the triangle), disc just below foil (to get the small gold). If your mineralization is low and there are no EMI sources in the area, try it a bit higher. If it becomes unstable, dial it back till it is stable. Keep the auto tracking on unless you're in an area where the ground mineralization changes very little. Go with a moderately fast sweep speed till you hit a target then slow it down over the target to get your best reading. Remember the quick start settings are printed on the bottom of the control box if you want to reset everything.
If you want quarters, you need to "cherry pick" the area you are hunting. Set the disc a bit higher; say around the nickel range, although you may want to set it to the coin only range (the #2 triangle notch) to eliminate pull tab signals. Don't dig anything but quarter icons when they come up. It will repeat on quarters during the sweeps if you are over one, although some of the deeper ones will switch between quarters and dimes, so you may want to dig those too. That M6 is pretty darned accurate when it comes to coins.
Thanks for the help,
