MX5 and jumpy VDI numbers
WhoDey, Nice find on the lock, looks old by the shape, any brass on it?
What settings are you using? Are you using the stock 9" coil? This info is always important, I listed my preferred settings in my above post. I usually run 2 Tone but will use 1 tone with first three iron segments notched out when I want to clear up a signal. I also use the 5.3 Eclipse coil in the trashy sections I run into, which is almost all the time. Jumping VDI numbers can be cleared up by doing a short sweep wiggle over the target center. The sweet spot on your stock coil is dead center as is the 5.3 coil, numbers will trend better if coil sweeps are centered over exact center of the target. I will use the pinpoint to find dead center and make a tight 3" sweep, sort of wiggle over the target.
...In my soil, 18 to 20 is a nickel, I dug up a man's 10Kt gold ring that gave VDI#s jumping from 25 down to 20. Wheat pennies in the mid 70's, Silver dimes in the high 70's to 80, 81 numbers, Silver Quarters in the 83,84, number range. I dug a deep wheat cent that was surrounded by nails and the VDI #s jumped from the 70's to the 50's with an occasional jump to the 40's. Adjacent trash Will alter VDI #'s too. Just dig and learn.