My 505 has greater depth in A.M. but I only use this mode when it’s not trashy ground or it will drive you crazy. It also depends on what I’m looking for. Seems to me A.M. works better for relics and such and Discrimination works better for coins and jewelry. In trashy areas I run in Discrimination mode but turned all the way down. This should detect everything (junk as well as good targets). When you hit a target, note depth and what the machine is telling you target might be. A good target should have a solid tone and repeating info being shown. A signal that jumps around as far as type of find and depth has usually turned up as junk for me. You can then pull off target, turn to A.M. and be sure to ground balance detector over ground with no metal in it, then go back to target and pinpoint it. Through trial and error I have found hunting like this proves OK for coin and silver but you have to watch the low tones (gold n nickles) cause you could mistake these for trash if you don’t learn how you detector picks up on them. You have to decide for yourself to dig or not. I haven’t mastered when to dig the lower tones so if I get them I still dig them all. Best thing to do is dig a lot of targets and remember what the 505 has told you about them before you did.
I have the stock 4” and 8-1/2” coils that came with the detector. I just bought a DD8”x11” and have run it only a few times. It definitely give greater depth and pinpoints well. Gone over ground that I’ve detected at least three times and pulled coins and a junk ring from same area. All targets were six to eight inches avg. The ring was at 9”. The DD is kind of pricey but I don’t plan on buying a different detector any time soon so I’m happy.
