After reading this thread, I decided the 223/77TMK might allow for an "ultralight mountain rifle" of sorts. I built a 3# 1oz (bare rifle) bolt action AR 223.
Took this ~6' boar at 350 yards. I don't normally need to shoot this far and I've only shot one black bear further than that (with a 308 Win), but that was as close as the conditions allowed. I was a little hesitant as this was literally the first shot on game I've taken with the 77 TMK...but after seeing the results in this thread, I was confident it would work as long as I could place the shot. Shot was broadside just back of the shoulder. Hit there or maybe an inch or so forward of that.
He ran about 40 yards, started to wobble and then ragdolled down the mountain about 100 yards into some willows in the pic. Death moan right after he stopped.
Worked well but the damage to the lungs was a little less than I expected after seeing the explosive pics in this thread. Impact should have been above 2000 fps. Regardless, I'd say the results on time to death on 30 some closer bears with 308/30-06 haven't been any different, other than I'd most likely have a pass through on the same shot and more blood trail (which I didn't need)...but those rifles also weigh a lot more than 3#.
Bear as found where he stopped rolling down the mountain.
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Lungs
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Top of heart
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Entrance in ribs
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Entance shoulder removed
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Far side shoulder removed with piece of jacket
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