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As I said, I test firearms and ammunition. A carbine slub can petrate 10 inches of pine with no problem. I also test penetration on the steel of pick-up truck wheels. 41 and 44 magnums will push their way through 1/8 inch steel leaving a dent around the hole. A carbine melts its way through before the steel has a chance to dent.
It's difficult for me to believe a carbine shot wouldn't penetrate clothing.
Many people don't understand what it takes to kill. When I was in the army the old sergeants used to remark when you hit someone with a lethal shot, they don't go down immediately. The carbine or even the 30-06 or .308 leaves a clean wound in military ammunition dure to the Geneva Convention. Hitting a man in the foreward midline with a carbine would probably blow out his spine and bring him down immediately. A side gut shot or lung shot would be lethal, but not before he attacked another 50 or 100 yards and fell. The average solder who sees his buddy die during that interval assumes the enemy isn't being hit.
As sighted, the carbine has an effective distance of 125 yards. There are quick sight adjustments on the weapont for greater distances. Not one soldier in 10 was trained to use those adjustments.
The 30-06 and 308 are a different matter. At 300 yards the slug is just getting started. On Fort Leonard Wood trainfire, before most people here were born, I hit 46 out of 48 lethal shots at 300 yards with a Garand. That was the limit of my eyesight with partially corrected glasses. Anything 300 yards away takes a bullet. Basically, If I cans see it, it's in big trouble. Whether the targe runs another 50 or 100 yards after being hit is inconsequential at that range. Right now we don't have a widely distributed service rifle that can do that. If a Garand or M14 were scoped, nothing survives at 500 yards. Yes, I know they are not designed to be scoped.
I would have been in favor of taking the carbine design, lengthening the cartrige by 1/8 inch, using 1/16 inch more lead and a more powerful charge.
Once I had an Argentine 1909 Mauser,(it was unfired when I got it) and my Nephew and I went to a large clay pit to do some plinking with it. We found a 10 gallon can partly full fo tar. My Nephew put it against the bank and stepped the distance as slightly over 400 paces.
I was fairly sure I could hit it as the sights were just about right on at that distance. The thing which really did surprise me is my Nephew who is not a serious shooter also hit it most of the time.
Do what? Unclear on your point.
The 20" M16A2 can certainly engage targets with iron sights to 500m effectively.
The 14.5" M4 SOPMOD/MWS with ACOG optic, or irons, is effective to at least 400m.
Since the overwhelming majority of infantry RIFLE engagements are under 200m, whether a rifleman can hit a large, exposed stationary target at 600m is mostly irrelevant.
Certainly, beyond 500m, 556mm has lost it's effectiveness, but inside 500m it performs quite well regardless of bullet weight, especially when fired from a 20" barrel.