Just how deadly is an AR-15 round?

I was on Twitter earlier and saw a post from Thomas Massie supposedly debunking the idea that the AR-15 is built to inflict the most damage possible. His argument is that a .223 or 5.56 is just a small round about the size of at .22. I know that’s true, but clearly there’s more to it than that. The AR-15 round travels at a much greater speed and so must deliver more energy. I don’t know the math on this, but just assuming more speed = more energy = greater damage. Also, I was reading some of the comments to his tweet and saw some people comment that the round tumbles once in the body and therefore inflicts more damage.

Now I have since read two articles: one from and army medic that says he’s seen hundred of bullet wounds and the 5.56 NATO round just punches right through and doesn’t actually do that much damage. The other was stating that the bullets tumble and come out the other side much larger than they went in. So which is true?

I am just curious as I have no compunction about a bullet doing the most damage possible. If someone is trying to harm me or my family, I want that actually.


The way I recall hearing it, the 55gr would become unstable & tumble after impact. The heavier 62 gr were more stable & likely to pass straight through. When you really wanna say FUCK you say it with hollow points☺


The earlier 55gr stuff tended to tumble. The newer 62gr not so much. Still on the battlefield it is better to wound the enemy so it takes resources away from the battle to care for the wounded. If he’s dead we just split up his gear and go on.


Girl, those things are dangerous. Simularly to the AR15 rifle itself, the 5.56 rounds have been known to jump right out of their box, unprovoked, and start chasing you around your house. But I have heard if you get a heavier round, they are slower, and you have a greater chance of out-running it. Just be careful.


Ok if you will respect my time in the Army as a combat medic… I wish to disclose something VERY important.
5.56 makes you bleed like hell… the most deadly thing in an active shooting is POLICE… They hold EMS and people who can stop bleeding away from people who need immediate intervention and cause more death than any shooter will ever be able to claim.
As a medic I never lost a solider due to GSW or even crush injuries who wasn’t already dead when I got there. Stopping the bleeding will prevent most fatalities from traumatic injury.
Make a tourniquet, a couple tampons and a nice occlusive bandage part of your first aid kit and keep it on you. You will save more lives than 90% of the EMS because you will be there and able to act when needed.


5.56 NATO from a 20 inch barrel (essentially the same as .223Rem, though .223Rem has a greater selection of projectiles, since it’s not restricted by international treaties):

55 grain - 3,260 ft/sec - 1,294 ft-lb of kinetic energy at the muzzle

62 grain - 3,150 ft/sec - 1,371 ft-lb of kinetic energy at the muzzle

7.62 NATO from a 24 inch barrel (same thing as .308 Winchester, though the 7.62 NATO is also limited on projectile selection, due to international treaties):

147 grain - 2,800 ft/sec - 2,559 ft-lb of kinetic energy at the muzzle

175 grain - 2,600 ft/sec - 2,626 ft-lb of kinetic energy at the muzzle

.223/5.56 is considered suitable for small to medium sized game, by hunters. Ground hogs and prairie dogs at longer ranges, coyotes at closer ranges.

.308/7.62 is a big game round.

.223/5.56 is quite a bit more powerful than most handguns, but quite a bit weaker than deer rifles. It’s a compromise between the two, giving up some power, in exchange for the ammo being lighter, more compact (can carry more ammo), and lighter recoil (doesn’t hurt the shoulder).


55 grain rounds tumbling, depended on certain factors being in the correct range (bullet velocity at point of impact, barrel twist rate, and probably a few other things I don’t remember). From what I’ve read, it was eventually determined to not be reliable enough to justify what they were giving up in effective range.

This was why they changed the barrel twist rate to 1 in 9" (from the earlier 1 in 12") and switched to 62 grain projectiles with the M-16A2 in the 1980s. The big trick with the 62 grain projectiles, is supposed to be fragmentation. If the bullet hits hard enough, the jacket breaks at the cannelure and the bullet separates into a few (3 or 4) pieces that can tear up more tissue than if it stayed in one piece and passed through. The problem with fragmentation is that it requires a high velocity at impact. Use a barrel shorter than 20 inches, and your bullet starts off slower. As range increases, bullet velocity drops, so fragmentation is less likely to occur as range increases. This is why troops with M-4s have reported poor performance with medium to long range shots, as the M-4’s 14.5 inch barrel gives up quite a bit of velocity, in exchange for a more compact weapon (the bullets pass through the enemy, doing much less damage than if the shot had been at short range).

Of course, when you remove the limitations of international treaties on military ammo, the above two concepts become complete garbage. Fragmentation would be called core separation in the hunting community, and is considered a sign of poor bullet design, as energy is eaten up by tearing the bullet apart, instead of using that energy to tear up meat. Tumbling would be an indication of poor bullet stability (not enough twist rate in the rifling) which would reduce accuracy at longer ranges.




There is a medical study that looked at the odds of victims of mass shootings surviving after being hit with handguns vs being hit with rifles.

As already stated in this thread, .223/5.56 makes you bleed. Survival largely depends on how fast trained medical help gets to you.

With deer rifle calibers, that window of time that help can save the victim, is considerably shorter, as the wound is going to be larger and more tissue is going to be torn up. Blood is lost faster, and the odds of organs being destroyed is greater. This is what those calibers are designed to do, as you don’t want the deer to run to the next county before it dies from blood loss.

With handguns, the wound is smaller, but the medical study found that victims of mass shootings involving handguns actually had worse odds of survival. The issue isn’t the wound size. It’s a matter of shot placement and number of times shot. By looking at autopsy reports, the study found that when handguns were used, the victim was far more likely to have multiple wounds, and those wounds were more likely to be in vital areas (head or center of the chest).

Just as compromising with .223/5.56 allows more rounds to be carried than with deer rifle calibers, it’s easier to carry a large amount of 9mm, than the same number of rounds of .223/5.56, which means the shooter might not be as concerned about stretching his ammo by taking only one shot at each person.

The issue of .223/5.56 having less recoil than deer calibers, also comes into play with handguns, as their recoil is even lower. The shooter can more easily make double taps and even triple taps.

All that adds up to higher statistical odds of ending up dead, if you are a victim of a mass shooting involving handguns.

Edit: https://www.reuters.com/article/us-health-gunshots/handguns-more-lethal-than-rifles-in-mass-shootings-idUSKCN1OU11G

“All of us were shocked. We came to the table with our bias that an assault weapon would be worse,”


Not a doctor in Chicago would be in the least bit surprised to hear this.


The author of this article is/was a combat medic , pretty gorey chit


I doubt tumbling on impact is limited to .223, I’ve had two G20’s that tumbled rounds before impact

its all antiguner propaganda anyhow , whats a bullet designed to do?

I would say its design is obvious, whats any rifle designed for, why would it be chosen IMO comes down to weight which equals capacity which = sustainability

Lighter rifle, lighter ammo means more ability to carry additional gear/supplies


Hideous as a rifle wound is THAT IS STILL VERY SURVIVABLE. Prep yourself and give yourself the ability to stop bleeding and you can deal with it… The people in those pictures are BECAUSE of this fact.


I’m going to stop calling my rifle an AR-15. Instead, I’m going to start referring to it as my MS-13, because then, even the Democrats will want to protect it




Gel tests with 300 grain Sierra Match Kings loaded in .338 Spectre showed that the bullets would start to tumble within 2 inches after entering the gel, continue tumbling through a 24 inch block of gel, then pass through the sheet of plywood that was used to hold the gel block in place, before getting absorbed by the berm.

No, it’s definitely not the only bullet known to have incidents of tumbling.


Robert, two G20’s that tumbled rounds before impact, was it ammunition specific did you ever determine the cause of the tumbling or is that a known thing with the G20.


Glock uses a different twist rate for the rifling in their 10mm barrels, than the twist rate used by aftermarket barrel manufacturers. I suspect that is at least part of the issue.


Never did no, still love the round :grin:


Admit it…youre just a 1911 snob