The base Montana is as light as 5#2oz in .338 Fed and goes up to 5#6oz in .223.....more steel left in the barrel. I have one of each, plus a 7mm-08. With LW Talley mounts and a Leupold VX3 2.5-8 x 36 (VH reticule) the .223 comes in at a touch over 6#s, and the .338 Fed with a Leupold VX2 2-7 x 33 at 5#12oz. I love the ergonomics on them. They are adequately accurate for their purpose, hold cold bore zero well for the first (and second) shot, although mine don't shoot great 5 shot groups if shot quickly. They can take a bit of work to find the right load, but heck that is part of the fun. Note that the .223 really didn't take any load work up and shot OK with all combos. The 7mm-08 was the most finicky and the .338 Fed was fairly easy to find a decent load for.
Kimber did not fix the weak firing pin spring when the 7-08 was sent to them, but my gunsmith did. It was the second Montana he had to fix with the problem. No big deal, just a 20 minute job that cost me less than shipping the rifle to Kimber did. If your rifle ever misfires, or opens and closes very easy while the firing pin is being cocked, that is a dead give away that the firing pin spring is too weak. Just get it fixed before it causes an issue in the field!