Of all the 5.56 vs drywall tests I've seen (and there are lots out there), they never make a hole in drywall larger than 5.56 unless it has yawed, and even then it is a keyhole no larger than the un-deformed round. To make "a huge hole" in drywall it would have to expand massively and immediately, and I've never seen a 5.56 round capable of expansion when hitting drywall. Even frangible rounds essentially turn into 3 or 4 projectiles after passing through drywall, but I'd never say 1/3 of 55 grains at 2000+ fps would "not significantly harm a person".
[0] http://www.olyarms.com/index.php?option=com_content&task=vie...
Relevant excerpts:
"Tests 1-6: Bare gelatin, heavy clothing, automobile sheet metal, wallboard, plywood, and vehicle windshield safety glass, were shot a distance of 10 feet from the muzzle."
"Tests 7-13: All involved shots through heavy clothing, safety glass and bare gelatin at 50 to 100 yards, concluding with internal walls, external walls and body armor at 10 feet."
"The Bureau’s research also suggests that common household barriers such as wallboard, plywood, internal and external walls are also better attacked with pistol rounds, or larger caliber battle rifles, if the objective is to "dig out" or neutralize people employing such object as cover or concealment."
"If an operator misses the intended target, the .223 will generally have less wounding potential than some pistol rounds after passing through a wall or similar structure."
Really unsure as to how you could possibly have come to that conclusion after reading the link....
Edit: now that I think about it, people unfamiliar with ballistic testing might not know that gelatin is almost always used to find out data about efficacy downrange regardless of what other things are being tested, so I can kinda see how you might take my comment at face value and feel that it was immediately contradicted if you didn't read the entire summary (which is a bit long).
I still say though, the original comment I replied to is mischaracterizing what happens when 5.56 hits drywall. It does not make a huge hole, and I don't know how you could say it "would not significantly harm" a person on the other side. See some tests here w/ photos regarding drywall and 5.56 penetration: https://www.theboxotruth.com/the-box-o-truth-14-rifles-shotg...
Pistol calibers very well may penetrate further after passing through drywall (as the FBI tests indicate) but there is no evidence to claim that 5.56 is less than lethal after passing through a sheet of drywall.
"The hypothesis turned out to be correct: V-Max bullets started fragmenting within the first sheet of drywall and completely blew to pieces on their way out of the second sheet, leaving dramatic craters." http://how-i-did-it.org/drywall/results.html
> Hollow point handgun rounds drastically reduce the danger of over-penetration present with rifle rounds for likely police scenarios.
Isn't really true anymore. There are modern cartridges for 5.56 that have great ballistics while in the air, and then very reliably dump all their energy into the first thing they hit, to the point where if you shoot drywall they will make a huge hole in it but not significantly harm a person standing a few meters behind it. If you are concerned about overpenetration, today it should guide your selection of ammo, not your weapon.