On mine, about 2 solid inches. Maybe a bit more in some
cases.. IE: I could get a quarter to hit at 11 sometimes
in an air test. Also the speed of the coil will effect
quite a bit. In general, the faster you swing it, the
deeper it goes. Also, in air tests, I had to crank the
sensitivity pretty high to get the max depth. So I run it
pretty hot, but then again I run em all pretty hot most
of the time... :/ BTW, as a comparison, with the stock
coil, my max range for the most part was about 7.5 inches
for a good signal. It was hard to get it to ring at 8 inches
on the air test with a quarter. Using the big coil extended
that "solid" range out to 9+ inches, almost to 10.. But my
big coil hits better at 10, than my stock coil does at 8.
So I consider it a good solid 2 inches at least. Maybe 2.5.
I don't think I could call it a solid 3 inches..
That may be a bit overly happy... Maybe a partial 3 inches
at times on some larger targets. It will turn the 250 into
a solid 10 inch machine, and a bigger sweep to boot.
MK