I’ve had a 223 Montana for several years now and I love it. I did bed the lug and tang and I adjusted the trigger, which the Kimbers are very simple to do that to.
The 223 definitely kills deer, but it doesn’t leave a blood trail like the bigger rifles, IME. I’ve also found that they tend to run a little longer. My deer bullet in that rifle is the 70 grain Speer, which does well, but probably not as good as the Barnes bullets that everybody loves.
This particular rifle shoots 55 grain SGK, 65 grain SGK and the 70 Speer very well and all to the same POI at 100 yards. The 55 grain loads make very nice, little cloverleaf groups.