I've been worrying about what Red said in post #5 above: "looks a bit
big on the M10"

Lawrence's fit chart clearly says the size 542 is made for the S&W M&P
with the 2" barrel. But knowing that Red is right 99.9% of the time I
did a little test.

I put my Model 10 with 4" barrel in the holster. The front of the trigger
guard comes within about 1/4" of resting on the welt, and the security
strap comes within about 3/4" of snapping.

It would probably be a perfect fit for a 3" or even 3 &1/2" barrel
Model 10. Maybe it was a special order and the just used size 542
because there is no size number for M&P with 3 or 3.5 inch barrels???

I know this is knit picking but I'm a serious student.

__________________
In Omnia Paratus