Up until yesterday, my only experience hunting big game with a .223 was when my wife shot an antelope buck 4 or 5 years ago with my AR at 200 yards using 62 gr Federal Fusion. Despite being a low/brisket shot the buck walked a few steps and bedded down. We moved in to about 80 yards and put one in the boiler room to finish him.
After seeing that and reading this thread, I wasn't very hesitant about getting a .223 set up for my kids to start shooting in the next few years, and so that I could try it out on some deer. I'm using 73 gr. ELD-M due to a 1-9 twist. (I went with a Savage 110 for a lefty compact off the shelf. 20" barrel. I know it's a Savage. But I won't really care when my teenager in 5 or 6 years drops it, lays it in the mud/rocks, or falls on it hiking in the snow.)
Deer #1 - Mature doe @ 420 yards. Quartering sightly away. Impact velocity 1970ish fps. Entrance was in the last couple ribs. Mule kicked and ran about 80 yards and crashed.
The bullet exited the ribs leaving a nickel to quarter sized hole, but didn't exit the offside front shoulder. I couldn't feel a bullet under the hide. The front shoulder had a lot of gooey bloodshot. I'm interested to see what kind of meat damage and bullet fragments I find when I butcher it.
Deer #2 - Mature buck @ 281 yards. Impact velocity around 2,220 fps. Low chest/heart shot. Entrance was touching the point of the elbow joint with a finger diameter sized entrance through the ribs. Took a chunk out of the side of the heart, and had a dime sized exit through the ribs, and broke the opposite front shoulder. I didn't break down the buck, so I don't really have autopsy pictures, but I could feel a piece of bullet under the hide on the broken offside shoulder so I cut it out and found a deformed chunk of lead about the size of a pencil eraser. Once again, interested to see what that opposite shoulder looks like.
At the shot he fell to his face but plowed forward for 10 yards before getting his feet under him. Trotted another 30 yards or so, stopped and looked up, then dropped.
My wife also took 2 deer. A 2 1/2 year old buck at 123 yds and a button buck at 270 yds using a 6.5 CM with 143 gr ELD-X. All 4 deer were hit in the vitals. All 4 deer were only shot 1 time. All 4 deer ran between 40 and 80 yards and all 4 deer were dead within 20 seconds of being shot. The 6.5 CM did leave bigger holes, but damage between the ribs was indistinguishable. I'm actually wondering if the 6.5 would have done less damage to opposite shoulders (she did not ruin any meat with her shots) because the smaller 73 ELD-M probably entered the opposite shoulder having fragmented to a point similar to buckshot rather than a larger bullet having more mass which would still have a larger mass/shank as it pushed into the shoulder? Or maybe it would just punch a bigger hole along with smaller fragments moving outward.
I couldn't ask for more lethal performance with my shot placement. Only difference is what size/shape of holes do you like in your carcasses.
Edit to fix wrong numbers.