Neal, the crosshairs will lock on a target untill the threshold comes back then it takes off and where it goes from there is anybodys guess but it will come back to your target or what ever you are swinging over.
I have found alot of silver dimes that don't lock far right and high, they will hit far right and high then hit over by the iron high left then back again to high right. I have learn to watch for this movement and most of all the tone, the tone of silver tells me it may be silver. The crosshairs move only when the threshold returns, try playing around with your sens, if your running manual try backing it off abit plus try semi-auto in trashy sites were there are alot of targets.
Last weekend I hunted a part of a park that was full of targets, so many that I couldn't hold a treshold in manual, had to back the sens way down to under 10, I put it in semi-auto and could hold a treshold around 26 and could hear all the targets, doing this netted me a 1900 barber quarter, 1906 barber dime and a 45 Merc. When I was in manual it would null but in auto it was hitting on targets, hope this helps Neal.
Ray ~