XDm

I've decided on getting an XDm, which caliber would be best for plinking?. 9mm or .40?

9mm!

I am also planning to put a red dot on it, or would it be better to do a 2x/3x scope?

What kind of mount is that on your Mosin?

I wouldn't hunt with a 9mm or a .40 to be honest.

Im sure there'll be people saying how bad the mount sucks compared to rock solid's mount but its the ATI mount but I used plenty of loctite on it and its holding extemely well. The scope is my $70 6-24x50 ncstar mark III rangefinder illuminated. Its cheap but pretty decent for the price, I just didn't see the point of putting something more expensive than the gun on it. I spent 3 hours cleaning it and let it sit in some CLP then spent another 30 minutes with hoppes no. 9 and got the bore nice and shiny and its very accurate now even with the cheap scope.

Its more of a just in case thing. It'll be more plinking/home defense most likely

if your planning on hunting with your xdm..id go 40. for just plinking 9mm is def cheaper on ammo. I use my xdm 40 for feral hogs and have had good luck with it.

Yup, what Spacemonkey said. I've used my .40 on hogs and it works fine, I use that cheap WWB 165 grain fmj stuff from Wal Mart. It's cheap enough at like 28.00 for a box of 100.

Id mainly use it for feral hogs and wild dogs