May also depend on what you mean by "all metal" mode. I think the 2500 has
an actual all metal mode which is continuous detecting, and is usually the deepest
seeking of the modes. But I'm not sure, being I don't have a 2500.
With the 250, to have the same sort of all metal mode, you would have to
run in pinpoint mode. Which I do quite a bit..
Now, if you just mean the non motion ID mode with all tabs un-notched, that should be
pretty easy to compare.
I don't have the 2500 to compare, but I can tell you what the 250 does.. Or mine anyway..
Doing an air test, my stock coil will detect a quarter 7-8 inches. The 9x12 coil
will do 10-11 inches. The sniper coil, 5-6 inches.
Of course, running in real ground could be a bit different. If hot ground, could end up
with less.
But with good ground, and coin leeching, etc, could be a bit more..
The 2500 "should" go a bit deeper than the 250. I'm guessing maybe 25-30 % worth,
but 2500 owners would have to chime in with reports.. I'm just taking a wild guess..
But even with the 250's lesser depth, it really doesn't mean a whole lot on the vast
majority of targets, as they will be within the 250's depth.
Sheer depth performance is nice, but in every day detecting it's not going to
be worth near as much as you would think. Nice for hard core relic detecting though..