AR-15 for Whitetail, 5.56 muzzle energy ~= 30-30
 

I was reading about the 30-30 cartridge on Wikipedia and noticed that its muzzle energy is roughly equal to the 5.56 NATO at about 1,800 ft*lbs at the muzzle.
https://en.wikipedia.org/wiki/5.56%C3%9745mm_NATO
https://en.wikipedia.org/wiki/.30-30_Winchester

When people talk about an AR-15 for hunting they typically reference the ,223 Remington as the round being used (excluding 7.62 NATO, 300 AAC, etc). Now, since most AR-15's are chambered for the higher pressured 5.56 NATO round I see no reason why you couldn't plan to hunt with hunting bullet loaded to the higher 5.56 pressures.
https://en.wikipedia.org/wiki/.223_Remington

Obviously, the 30-30 is a well respected deer round. So, why arn't people discussing using a heavy for caliber round loaded to 5.56 NATO pressures to produce energies matching the 30-30 when talking about hunting with an AR-15? Why do I only see threads talking about the ~28% weaker .223 Remington loading?

What am I missing guys? Educate me. :deer:

EDIT: I was informed that my #1 mistake was I misread the muzzle energy of the 5.56 as ~100 ft*lbs when it is, in fact, 1800 JOULES which is about 1300 ft*lbs, right in line with the .223 (as one would expect). This basically eliminates the entire question/argument.

In some states a 223 can't be used for deer so check your state laws. I used a 222 for many years for deer. Never had one get away. Just don't use a varmit bullet for deer. You can buy bullets made for medium size game. Everybody has their own opinion on what caliber to use. I read about guys that think you should have a 30 cal or larger. Shot placement and distance is the key. If it is legal use it.

Thanks for the info. It is legal here but my question is more academic than practical. I've got a .308 Bolt Action which is my primary and I recently picked up a Marlin 1895G in 45/70 that I want to take out... no one will complain of that one being too wimpy! ;)

The question stems from the fact that there are many people feel the .223/5.56 isn't suitable for Medium Game. Very few people think the 30-30 isn't suitable for Medium Game. It appears as though the 5.56 muzzle energy is equal to the 30-30 and thus it seems that with the correct bullet you should be good to go. Trying to figure out my own opinion and am looking for information that would "disprove" my theory.

I just got done with this Chuck Hawks article on .22 caliber cartridges for big game
http://www.chuckhawk..._cartridges.htm


It was very informative and doesn't bode well for my theory as the bulk of it discussed a .22 caliber round on a case designed for more powder than the .223/5.56! ;)

Muzzle energy never killed anything.How many deer you seen shot at a range of 2 ft?

What is the energy at 100 yards? The heavier bullet of the 30 cal will be higher than the energy of the 22 cal at hunting ranges. Sectional density and ballistic co-efficiency mean a lot more than muzzle energy. I've been told you need 8oo ft lbs of energy to ensure adequate penetration on deer sized game.

Additionally, few game animals differ so much in body size than whitetails do. An average buck in TX or most the Deep South will not make 200 lbs on the hoof. But a buck in ME or MN or Canada will go well over 300 lbs. While a .223 may work on the smaller deer I sure wouldn't want to take on a big Northern or Mid-Western buck with it.

I've got a fair amount of combat experience with the 5.56 and have seen what it does to flesh. It makes a bad surface wound but often doesn't get really good penetration. Remember it is a military round and you can take more guys out of action by wounding than you can by killing. Dead men can stay where they fall but wounded need to be transported and that takes additional guys.

In my opinion, the .223 is a heck of a coyote round but it isn't a deer round.

Reality Check Time...
 

Ask and ye shall receive...

First off, getting 1800ft.lbs. out of a .223rem is a stretch. I'm not sure I've ever gotten that much, and I know my current loads don't.

Second thing:

Energy is one thing, penetration power is another.

Many people are actually confused about what generates penetration. Newton's law is about the conservation of MOMENTUM, not energy. The impact MOMENTUM of a round is much more important than the energy. Both Kinetic Energy and Momentum are inherently linked since they both depend on bullet mass and velocity, but momentum varies proportionately with both mass and velocity, whereas energy varies proportionately with mass, but EXPONENTIALLY with velocity. A little speed goes a long ways for KE, but not very far for momentum. Double Speed, you double momentum, whereas it would quadruple your KE. Momentum is what is conserved during an impact, NOT energy.

So I look at a round's Momentum, not just KE.

Another factor that is very commonly used to determine a given cartridge's stopping power is "Taylor Knock Out Factor". The TKO factor is the momentum of the round times the diameter of the bullet: bullet weight in grains x velocity in fps x bullet dia in inchest / 7000. In a nutshell, this is used to determine how hard hitting a given cartridge can be. For example, a .30-06 with 150grn bullet at 2950fps (been using this load for 15yrs) = 2898ft.lbs. KE, whereas a .45-70 shooting 325grn Hornady FTX's (my wife's preferred load) at 1790fps = KE of 2312 ft.lbs. BUT... When you compare the momentum or TKO of the two, you see why the .45-70 hits so hard: .30-06 TKO = 19.5, .45-70 TKO = 37.6!!!

So let's talk some numbers:

.30-30winchester, VERY easy to find 2200fps loads with 170grn pills.
1827ft.lbs.
16.5 TKO
53.4 ft.lbs./sec momentum

.223rem my favored coyote load is 50grn @ 3420fps
1299ft.lbs.
5.5 TKO
24.4 ft.lbs./sec momentum

Heavy .223rem load for hogs and long range play, 69grn @ 2840fps
1236ft.lbs. Kinetic Energy
6.3 TKO
28.0 ft.lbs./sec momentum

So even though they aren't that far spread in terms of energy, the .30-30 has around twice the impact momentum, and about 3x the TKO factor for stopping power.

Double Check your link. The Wikipedia page for the 5.56Nato has JOULES, not ft.lbs. There are no loads on that page that are 1800ft.lbs., they are 1800 JOULES, which equates to 1200-1300ft.lbs.

So yes, there is a big energy gap between the .223/5.56 at 1200-1300ft.lbs. and the .30-30win at 1800ft.lbs., and farther still between their momentum and TKO stopping power factors.

That said, yes, the .223rem will kill deer, I've knocked down several in TX with a .22-250. But no, it's not the equivalent of the .30-30, not by a long stretch.

Great writeup! Very informative. I'm an engineer & I like math so I'll be reading your post another couple times to make sure I grok it all. I've got a scoped .308 Win bolt gun. I want to get a 30-30 lever gun and use it with a peep sight for shorter range & mobile work.

Thank you! You've "solved" the biggest mystery I had. Damn units! They'll get you every time. I was very surprised that 5.56 pressures would push the round so much faster than the .223 pressures but I *thought* I saw the numbers but didn't notice they swapped units on me. That makes the KE corroborate the rest of the information. If fact, if I had noticed that it was in Joules I would never have written my original post in the first place!

the 223/5.56 with a good bullet will kill deer, question is can you find them once they are dead, and its not that easy trust me, chrony any 5.56 load and show me its 28% faster than a 223 or even has 28% more energy, shot in the proper firearms it may be 28% higher in pressure but they are much closer than you think.
RR

To me if u can rifle hunt want an ar why not go 7.62/308. If the. 5.56 was all i had to hunt for deer i would and did but not my first choice To me better to go bigger then what u need for a min. My hunting gun is gonna be a 308 ar im pretty sure if i hit the shoulder it will blow through with enough energy left over a 223 idk prob but to me we owe it to the deer to put it down quickly and recover it

I no longer think it is 28% higher energy... stupid Joules to Ft*Lbs conversion ;)

Yet another illustration of the difference between assumptions based on numbers on a page as opposed to experiencing things in the field for yourself. Hunt with a 22 centerfire long enough and it will teach you 2 things:

1) A 22caliber centerfire can easily kill a deer.
2) A 22 caliber centerfire is not a good choice for deer.

I CAN drive a nail with a wrench, but that doesn't make it a hammer.

What flavor of engineer are you?

Electrical

I'm a Chem E, had a physics minor among other things. Done a lot of shooting/hunting in my life, a bit of ballistic product engineering & development in the past (some private/commercial, some military), and a lot of mathematical/physical analysis and modeling of ballistics. If you ever want to nerd-rap about all things ballistic, hit me up.

Awesome Nomercy! I'll shoot you a PM as I start learning more (and having more questions) ;)

In the meantime I've been limiting my investigation to factory ammunition (mostly for my .308 Weatherby Vanguard Series II) and looking at ballistics caluclators to see where I wanted to sight in my rifle. I ended up choosing a 24 yd zero. This provides for a 2nd zero at about 225 yds and a point blank (+/- 3") range of 0 to about 275 yds. In my limited experience in GA, there arn't any shots longer than that hehe.

I haven't messed with crosswind and any handloading. My scope is a Nikon ProStaff 3-9x40 and it doesn't have on-the-fly adjustable turrets so I havn't planned on doing anything but a manual holdover for estimated range.

Weatherby guarentees sub-MOA @ 100 yds with "premium factory ammunition" such as the Federal Power-Shok 150 grain Soft Point(308A) I chose (not too expensive, recommended by Weatherby).

Whether that is true or not ultimately depends on your particular rifle and load. At any rate, the most important thing you MUST do is shoot your rifle enough at any range you will be hunting to KNOW where it hits, not just where the calculator SAYS it's supposed to hit.

Keep in mind that it's not universal either. Sighting in this winter at 24yrds might mean you're zeroed at 225yrds for now, then end up being 5" higher come summer time. Zeroing on the delta in Louisiana then hunting elk in Colorado high country might mean you miss by 8".

As they say in engineering school (used to at least), "garbage in, garbage out". If the conditions you feed the calculator don't match your actual conditions, no matter how good the math is, you're not going to hit what you're aiming at.

Wow, those are some big words ;)

I totally agree, but you gotta start somewhere. That and it is frickin' painful to find a decent outdoor range near Atlanta, GA :/