Blue Force Gear Quote of the Day: Caliber War!

5.56 (coutesy loaddata.com)

“5.56 can’t complete with hunting cartridge bullets, which can legally be expanding hollow point that are more lethal than tumbling. Their lethality is based entirely on how powerful they are. 5.56 is only half as powerful as the 7.62 NATO (.308) hunting bullet. That doesn’t mean I’m not pleased to see AR-15s sell on the civilian market. It just means I didn’t realize they would 57 years ago. And I’m not on the wrong side of any gun issue unless someone wants to argue that an infantry rifle cartridge should kill a cavalry horse at 1,000 yards (30-06 criteria).” – Jim Sullivan, AR-15 Inventor Says HBO Grossly Distorted His Views On Guns [via thefederalist.com]

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comments

  1. avatar Ben says:

    Psychological effect of being shot with any caliber?

    Devastating

    1. avatar Gov. William J Le Petomane says:

      That’s true for conscripts. Jihadis? Not so much.

    2. avatar James in AZ says:

      Only when they realise it, and care about it

      Methheads and goatfvckers need not apply

    3. avatar jwtaylor says:

      This has not been my experience. I’ve seen plenty of people shot that barely registered. I’ve even had a civilian shot 3 times in the chest at close range with an AK47, walk into my clinic for treatment. I’ve shot men, center mass with a 556NATO, only to watch them lean back over and continue firing.

    4. avatar RealityCheck says:

      ” Psychological effect of being shot with any caliber? Devastating.”

      This is simply not true, and it’s one of the myths about armed self defense that has to be combated. Believing this myth will get people killed.

      Are some people psychologically affected? Definitely. But can you count on it? Most definitely not!

      Here’s a fun example of why shooting an angry russian in the leg isn’t necessarily going to cause a devastating psychological stop:

      1. avatar int19h says:

        It’s a rubber bullet gun.

  2. avatar CRF says:

    Media distorting someone’s words to fit a slant? Say it ain’t so!

  3. avatar Sian says:

    A media source willfully distorted what someone said to further their own agenda??? How can this be??

    1. avatar NYC2AZ says:

      Shocking! Next they’ll tell me that the media has a narrative and they aren’t interested in reporting the facts!

  4. avatar Surivordude says:

    I’m a 308 guy myself, but come on! Getting shot with 556 isn’t going to be like getting shot with an Airsoft pellet. It kills you just as dead as 308. It’s just 308 makes bigger holes, goes further, and punches through more stuff.

    1. avatar James in AZ says:

      According to medical poopfessionals, the “bigger hole” is a fantasy, unless you step up to the magical 50bmg

      1. avatar dh34 says:

        5.56 and 7.62 are fine if you just need to put something/someone down. It takes .45 ACP if you must delve into the world of magic and kill their soul.

        1. avatar Bob15 says:

          Hahaha! I love it.

  5. avatar Mr. 308 says:

    “Their lethality is based entirely on how powerful they are. 5.56 is only half as powerful as the 7.62 NATO (.308) hunting bullet.”

    That’s what I’m talkin ’bout!

  6. avatar Gov. William J Le Petomane says:

    Currently I’ve bumped up my defensive rifle to a .30-30. Federal makes a 125gr. hollow point that makes a 2 liter bottle of water explode like you dropped a hand grenade in it. I figure it will do anything I’d ask an unscoped rifle to do. Passed 400 yards the 5.56 probably has an edge with expanding ammunition, but if I need a defensive rifle at that range I’ll grab my .308 with it’s 12x scope.

    1. avatar Chris. says:

      If you need a defensive rifle for 400+ yards, I’d say you need to rethink some life choices.

      1. avatar James in AZ says:

        If “defensive” means home defence, yes

        If “defence” is what the military think it means, which means anything tacticool, not so much. The 2nd Amendment doesnt have a range limit and we need long-range capabilities as a deterrant

      2. avatar James in AZ says:

        *deterrent

      3. avatar Defens says:

        Some people “have” rethought life choices, and have moved from the urban jungle to areas of the country where a defensive perimeter may well extend out a few hundred yards. It’s not inconceivable to think of a defensive rifle use at much farther than “bad breath” distance – in fact, I was on the cusp of being in such a situation (defending my Dad) myself.

        Don’t assume that everything you read by experts is true – and don’t be trapped in a box that assumes that your experience is applicable to everyone else. I live on acreage in a rural area, far from police backup. There are also meth labs (or whatever else they cook up these days) in places like this, and home invasions, while very rare, still do occur. The need for a rifle (v. pistol) and potentially shots out to 50 yards is indeed a factor for me and my neighbors.

      4. avatar Gov. William J. Le Petomane says:

        If I ever need a defensive rifle passed 400 yards I’d say it’s a little late for rethinking life choices.

    2. avatar uncommon_sense says:

      A .30-30 Winchester rifle launching a 125 grain hollow-point bullet at 2,570 fps is a nice little bump up from from the venerable 7.62 x 39 mm cartridge … and would have to be pretty devastating out to about 150 yards. At 200 yards, that bullet would be travelling at about 1600 fps and represent a close match to a .357 Magnum 125 grain bullet at the muzzle. While that round typically stops attackers immediately, some might still keep chugging along.

      At 300 yards that bullet is down to 1300 fps and represents unimpressive handgun ballistics. Of course no one would not want to be in front of it. I am simply pointing out that a hit at that range would not necessarily take someone out of the fight at all. A .308 Winchester 150 grain hollowpoint bullet at 300 yards, on the other hand, would be almost guaranteed to immediately take someone out of the fight. (The Federal Premium .308 Winchester 150 grain Vital-Shok bullet with Nosler ballistic tip would still be moving at 2,200 fps at 300 yards.)

      Thus at 300 yards:
      .30-30 Winchester 125 grain bullet == 1,300 fps
      .308 Winchester 150 grain bullet == 2,200 fps

      1. avatar Gov. William J. Le Petomane says:

        True enough. But by slipping a Hornady Leverution in the pipe the .30-30 hits with 1000lb/ft + of energy at 300 yards. Still no .308, but compared to M193 bullets that won’t tumble at that range you’ve got a pretty devastating carbine with 2/3 the recoil of a .308.

        1. avatar uncommon_sense says:

          The 160 grain Leverevolution hitting at 1,700 fps at 300 yards is definitely better than 55 grain, 5.56 mm at 300 yards. As for terminal ballistics at that point — it depends on how slow the Leverevolution bullet can be travelling and still expand reliably. I have no idea.

        2. avatar Gov. William J. Le Petomane says:

          Federal Fusion is also a good load for .30-30. They claim a little higher BC than most (boat tail?). I’m keeping the 125gr. in the mag since I live in town and it shouldn’t be prone to severe over penitration, which I believe would be a major problem with a defensive .308.

          Anyway, I sold my Mini-14 and wanted a lever gun, so I basically had the choice between.30-30 or a pistol round carbine. A lot of people like the .44 mag lever action for defense and you get a 10 round magazine with that, but passed 100 yards the .30-30 performs much better. I figure the outer limit of the .30-30 is around 400 yards where as the .44 would be about useless passed 200. For defensive purposes that is, for hunting cut that in half.

          I’ve only had it out once and I’ve done very little open sight shooting, but I managed about 4 MOA groups at 100 yards. That should improve with practice. Still I feel confident that I could put most rounds in 12″ @ 300. The front bead (5/64″) constitutes 10 MOA so +5 MOA @ 100, 0 @ 220, and -5 MOA at 300. Just cover the target @ 300.

          And I already have a .308. Huge fan, but it seems like a waste shooting .308 without a scope. If the s#!t really hits the fan I’ll be hiding in the bushes with my .308 on the bipod and my .30-30 slung across my back.

          Unless I finally break down and buy that .338 Lapua I’ve been wanting.

        3. avatar int19h says:

          Bullets will tumble at any range. The problem isn’t that M193 won’t tumble, it’s that it won’t fragment. It’s fragmentation that produces a massive permanent wound cavity, not tumbling.

          Anyway, if you want a close-range man-stopper, I would rather look at large caliber AR choices, like .50 Beowulf, .458 SOCOM or .450 Bushmaster. You still get the convenience of the AR platform, the ability to quickly swap mags etc. On top of that, compared to .30-30, you get ~50% more energy in a significantly larger and heavier bullet; and the option to go subsonic and suppress.

        4. avatar Gov. William J Le Petomane says:

          Not bad choices, int. My only qualms would be the lack of $500 rifles and 60 cent ammo. I’m also well aware of the extremely remote likelihood of ever actually needing a defensive rifle in the first place, let alone 30 rounds of moose dropping energy. If I was looking for that I’d probably just go the AR10 route. If it walks on two legs a .308 will drop it pretty efficiently (as will a .30-30).

        5. avatar int19h says:

          If you already have an AR pistol lower, you can get a complete .458 SOCOM upper for just over $600:

          http://www.radicalfirearms.com/category-s/2088.htm

          So not quite $500 rifle, but not as far from it as one would expect.

        6. avatar Gov. William J Le Petomane says:

          Sigh, so many calibers, so little time…

          My wife has the AR but it’s a rifle. It was a gift from her brother with permission of the court. He thinks he’ll get his rights restored, but I doubt it.

      2. avatar Sian says:

        After one or two .357 equivalent hits, they’re going to have a hard time hitting you back from 300 yards away. XD

        1. avatar uncommon_sense says:

          After two hits, very true.

          After one hit to a leg, forearm, or edge of the body, I don’t know.

        2. avatar Gov. William J. Le Petomane says:

          All depends on how many virgins they have waiting for them in paradise.

      3. avatar RandallOfLegend says:

        I shoot and reload a lot of 357 magnum. You might be able to get the performance you are quoting out of an 8 inch barrel. Out of a reasonably long 4 inch barrel a 125 grain bullet is traveling 1300-1400 fps at the muzzle. And that is not “unimpressive”.

        1. avatar Gov. William J Le Petomane says:

          Most of the ‘standard’ loadings are ~1450fps from a 4″ vented (test) barrel, but those are actually not full pressure .357 loads (thanks to Smith & Wesson -cough-K-frame-cough-). Go with Buffalo Bore or Double Tap, etc. and you should get close to that out of a 4″ barrel.

          Also, a .308 125gr. has a much higher sectional density than a .357 125gr., in any case the penetration would be better.

    3. avatar Ing says:

      Where the heck do you get those 125 gr. hollowpoints? I’ve never seen any in the wild, and I want some.

      1. avatar Gov. William J Le Petomane says:

        I picked up a couple boxes from sgammo.com. Check ammoseek, they’re out there. Sportsman’s Warehouse also stocks them. Federal lists them as a ‘varmint’ round, but they look just like the semi-jacketed hollowpoints I stick in my .357 mag. 2570fps (24″ barrel), which is slightly less powerful than the 150-170 grain rounds. Sectional density is still higher than a 158gr. .357 or 240gr. .44.

        I tried making 2/3 full 2 liters fly by shooting them low. A .357 hollowpoint sends them flying 10-15 feet in the air. Looked more like Old Faithful in fast forward. Even the one I shot with a .308 didn’t blow up like that.

  7. avatar RockOnHellChild says:

    The .223 wouldn’t be my first choice as a hunting cartridge, but it wouldn’t be my last, either.

    My goal is to drop them where they stand – humping a limp carcass long distance is not my idea of a good time.

    The closer I can down them to my truck the better. If I could figure out how to get them in the bed of my truck before I take the shot, I’d be tickled pink.

    1. avatar 16V says:

      In most states I know, it wasn’t legal for medium-size game (deer) until rather recently.

      I believe all animals that one hunts deserve the dignity of a speedy dispatch – and the plastic pop-gun round doesn’t guarantee that nearly as well as a 30-30/30-06 whatever.

      .223 was for hunting rabbits, wolves and prairie dogs at a distance. Oh well, can’t stop the mall ninjas from hunting with that rifle, just hope they learn to track their game.

      1. avatar Bob says:

        Yeah I see your point. However I hunt with my AR-15. Where I hunt, I’d be hard pressed to get a shot over 50-60 yards. There’s plenty of energy at that range, as the last 8 point buck I got was dead-right-there. Quite a mess was made of the heart-lung area.

        Would I want to use an AR15 in wide open spaces? No. The deer must be within the mall for this ninja. Ha!

        The problem is, not everyone understands this, and stays within the effective parameters of their hunting weapon.

        1. avatar 16V says:

          As long as your game is inside the food court, it’s all good…

          if it works for you, and your state allows it, it’s none of my business. One can take a deer with a .22lr if need be, and it’s close enough. I’m an older guy, we were always taught to have more rifle than we need for the game we sought. That and there’s a lot of woods in the midwest.

      2. avatar int19h says:

        Apparently, .223 is legal to hunt deer in Germany, and people use it for that purpose. The anecdotal evidence that I have from some people that I know there is that it’s a fairly reliable one-shot killer, at the very least not any less so than .30-30 and other cartridges traditionally used for deer.

    2. avatar Curtis in IL says:

      All you need is a ramp and some bait.

    3. avatar Ed Rogers says:

      ^This.

    4. avatar Ed Rogers says:

      Rockonhellchild has perhaps the best point. If I’m going to hunt, I want to make it as easy on myself as possible.

    5. avatar Wiregrass says:

      I have some 65g soft points that I hand loaded and I’d like to see for myself how they do on hogs or smaller deer. They are the most accurate round I have found out of my AR-15. I’ve seen a lot of photos of people with game claiming these did the trick. Still I agree with you that .223 is not the ideal round for big game. My 30-06 saves me a lot of tracking.

  8. avatar Mikele says:

    The MSM edited a gun story to make the author seem to agree with the liberal agenda?!?!?! Whaaaa?!?!? The outrage! **Sarcasm**

  9. avatar Pwrserge says:

    Because 77gr OTM pills are not a thing?

    1. avatar James in AZ says:

      They are

      I think the guy means pills that reliably expand to create bigger permanent and temporary channels by design are better than just tumbling. A bigger frontal area means a larger permanent cavity, and more resistance as it passes through tissue. As per Newton, more resistance means more force exerted on the tissue to create an irrecoverable (is that a word?) stretch, thus a meaningful temporary cavity.

      Tumbling certainly is better than straight-through. But it seems to depend on more factors (contact angle, medium thickness, and how the stars are aligned) than expansion

    2. avatar BillC says:

      This was taken out of context on purpose by HBO. J. Sullivan was specifically referring to the military use of hardball 5.56, when the it was initially designed to cause trauma by means other than expanding.

      HBO, had it say in the same breath, that 5.56mm is just too powerful and dangerous for civilians because of the damage it could cause on people.

      So they are both saying it’s a “stupid” choice for civilians because it’s too weak, and it’s too “dangerous” for civilians. They are trying to have it both ways.

    3. avatar int19h says:

      5.56 OTM bullets don’t expand, they fragment.

  10. avatar Shire-man says:

    Caliber wars are a silly waste of time on par with debating super hero fights and other fanboy tropes. If you shoot it well and can afford to keep it fed that’s all you need concern yourself with. Any number of things are more constructive than rambling on about how blah blah is better than blah blah because blah blah.

    Or let’s just take this quest for the one-shot killer to its logical conclusion and arm only with noob-tubes and rockets.

    1. avatar uncommon_sense says:

      Shire-man,

      I believe caliber and terminal ballistics discussions are useful/interesting on two fronts:
      (a) For people who want to eek out the best odds of prevailing over their attacker.
      (b) For people who are curious about the subtle differences in calibers.

      Certainly, having a firearm at hand when someone attacks is by far and away the most important consideration. If we could somehow assign a percentage to how important different facets of self-defense are, perhaps having a firearm is 90% and which caliber or bullet construction is the other 10%. For some people, they even want to optimize that remaining 10%.

      Think of it like golf clubs. Some people could care less what 5 iron or 3 wood they have as long as they have decent success putting the golf ball on the fairway. Others will be concerned about which specific 5 iron or 3 wood they have because they want that extra 10 yards on their drive … or they want their shots to be more centered on the fairway. Neither golfer is right nor wrong. Whatever suits their personal preference. The same goes for firearms and caliber/bullet choices.

      1. avatar tdiinva (Now in Wisconsin) says:

        Skill in golf is more important than in shooting. You have to be able to dial in exactly 122 yards for the club to make a difference. You are generally going to the same accuracy with a long gun of almost any caliber.

    2. avatar Gov. William J. Le Petomane says:

      Still, it’s more entertaining than the Kardashians.

    3. avatar Joseph Quixote says:

      Actually it is important especially if you are hunting elk, moose or big bears. While it is certainly possible to take larger game with a .223, the round was designed for beings around 160 pounds. Shooting a coyote, a doe white tail or a close in hog with it is probably humane but don’t tell me that shooting a 700 pd bull elk with a .223 is the same as hitting one with a .300 win mag. We were always taught to bring more rifle to the game than what was needed so that the animal does not suffer. On top of that, tracking a wounded elk in driving snow over 9 to 12,000 foot mountains well make you question your sanity and why you shot the damn thing in the first place.

  11. avatar Matt in Oklahoma says:

    The number of people who talk and write that don’t actually kill with guns is staggering. Use the proper tool for the job and use what you have when you have to.

  12. avatar Wiregrass says:

    Another good example of why you don’t trust the mainstream media.

    But I’m still trying to figure out how 1:14 is the right twist for the standard 5.56 NATO round since they found they needed something faster for stability.

    1. avatar Rambeast says:

      That is due to the .223 designed to be a 40gr pill fired from a 20″ barrel being stabilized just enough for steady flight, but unstable enough to tumble at high speed. The 1 in 7 twist is used for 62+gr pills out of 14.5″ and shorter barrels.

      Twist rates are to be used for specific weights (lengths) of bullets to achieve the desired effect. SP and HP rounds like fast twists (over stabilization) to keep them flying straight when they hit flesh to insure proper expansion and penetration. FMJ rounds meant to tumble are just barely stabilized to be accurate but yaw and fragment on impact.

    2. avatar int19h says:

      1:14 will stabilize the original 55gr bullet that they have used, at least in a 20″ barrel, but it’s basically on the verge of stability, and that affects accuracy, especially when temperature and humidity fluctuate. So the military requested the twist to be changed to 1:12 for the sake of accuracy.

      The current standard 62gr NATO round is best handled by 1:9 twist, and many European assault rifles use that (e.g. AUG, FAMAS). 1:7 is a compromise between that, and the 1:6 twist that is optimal for the standard tracer round, to permit firing both.

  13. avatar James in AZ says:

    Enjoy the calibre war all you want

    Meanwhile, stock up on whatever decent ammo you can get and practise, and be done with it

    1. avatar Andrew Lias says:

      That’s why my latest AR is in 9mm. Dirt cheap reloading, so more range time!

  14. avatar Andrew Lias says:

    Recording interviews should be a part of the rules of engagement for PoTG, or simply a “no comment, I have little intention of helping you and your biased agenda.” No need for clarification later on that could be conceived as back peddling.

    1. avatar Dyspeptic Gunsmith says:

      PotG should know, a priori, that journalists are a pack of mendacious, agenda-driven, drama queens. They’re destroyed by a calm recitation of the facts.

      However, you have to be sure that you defeat the clowns in the editing room as well as the bimbo in front of you. Towards that end, PotG should always, always, always bring their own recording equipment to any interview. If the journalist won’t agree to you recording them (and you), then refuse to speak to them.

      Oh, and it goes without saying: record their refusal to allow you to record your interview.

  15. avatar Cameron b says:

    While I don’t consider my 223 an all around rifle caliber it will and has dropped the small deer and large pigs in my Florida hunting grounds. Just like the guys that hunted with the 250-3000 a century ago: small bullets placed in the right spot do the job as well as a bigger bullet. I’d rather use my 30-06 because it can and will drop or incapacitate animals with marginal shots both in placement and distance.

  16. avatar TruthTellers says:

    6.8 Remington SPC for the Save!

    1. avatar mike says:

      Kudos for representing…. but even Remington abandoned you a while ago 😉

      1. avatar jwtaylor says:

        Mike, that usually means you are on the right track.

  17. avatar Tom in Georgia says:

    I hate to say it, but anyone naive enough to associate with that open, festering sore known as Bryant Gumbel richly deserves everything they asked for. Seriously?

    Tom

  18. avatar uncommon_sense says:

    I have not read/heard the original source article. I will simply comment about 5.56 x 45 mm caliber. I have always heard that the various non-rimfire .22 calibers like .222 Remington, .223 Remington, and 5.56 x 45 mm are varmint calibers. They shoot light bullets at something like 3,000+ fps from 20 inch barrels. Of course all of those are overkill for small critters (varmints).

    Can a 55+ grain, .224 caliber bullet stop human attackers? Absolutely. The more relevant question, in my mind, is how fast and how reliably can a .224 caliber bullet stop a suicide attacker and out to what range? As far as I can gather, a decent hit with a 55 grain, .224 caliber hollowpoint (e.g. expanding) bullet is almost always going to immediately stop a suicide attacker out to about 150 yards or so. If you want to immediately stop a suicide attacker beyond that, then I think you need a heavy-for-caliber expanding bullet like Hornady’s 75 grain boattail hollowpoint that is still humping along at 2,240 fps (836 ft-pounds energy) at 300 yards.

    Much beyond 150 yards for 55 grain hollowpoints and 300 yards for 75 grain hollowpoints and you rapidly get into handgun velocities/energies that are anything but guaranteed to immediately stop a suicide attacker.

    Of course, if you are not concerned about having the ability to immediately stop suicide attackers, then 5.56 x 45 mm will almost always do the job at any range as long as you can actually hit your target.

    1. avatar mark s. says:

      22 WMR ( 30 – 50 grain ) , ( 20,000 rounds ) 3 rifles ; 1 iron sights , 1 scoped at 50 yards , 1 scoped at 100 yards
      223 ( 55 – 75 grain ) , ( 20,000 rounds ) 3 rifles ; 1 iron sights , 1 scoped at 150 yards , 1 scoped at 300 yards
      30.06 ( 80 -220 grain ) , ( 20,000 rounds ) 4 rifles ; 1 iron sights , 1 scoped at 300 yards , 1 scoped at 500 yards and 1 long range monster with your finest long range scope .
      ………… done .

  19. avatar mike says:

    Speaking of 556 and 308…. 300 BLK sits in the middle and takes a big bite out of BOTH of them in many aspects.

    1. avatar Warren says:

      Built an AR10 for hunting hog, and an AR15 pistol for HD. Gonna start an upper for the pistol in 300BLK to fill in the spectrum a bit and give myself something for deer. I was slow to accept 300BLK, but I’ve finally been sold on the value of the round.

  20. avatar Panzercat says:

    Here’s a novel concept— Put a hollow point on a heavy grain 5.56 and call it a day.
    No, really. That’s sarcasm.

  21. avatar uncommon_sense says:

    After a lot of research and some experience with terminal ballistics on white-tailed deer, I have come to three conclusions:
    (1) Huge bullets (.44 caliber and up) at “slow” velocities (1,100 to 1,400 fps) promptly kill white-tailed deer.
    (2) Small bullets (.30 caliber and below) at “fast” velocities (2,400 to 3,000 fps) promptly kill white-tailed deer.
    (3) Small bullets at “slow” velocities (less than 1,600 fps) do not promptly kill white-tailed deer.

    Shot placement with small bullets is critical between 1,600 fps and 2,400 fps and whether or not such a bullet promptly kills a white-tailed deer varies considerably.

    How does this translate to self-defense against human attackers? The larger and faster a bullet launches from your rifle, the greater the probability of any hit at any range being able to promptly stop your attacker.

    1. avatar tdiinva (Now in Wisconsin) says:

      That is a fancy way of saying shot placement is not idependent of caliber. The smaller and lighter the bullet the smaller the area that defines good shot placement.

      1. avatar uncommon_sense says:

        tdiinva,

        Ah, yes, thank you. You have stated the principle in a very succinct manner.

        I would add one more dimension to your statement:
        The smaller, lighter, and slower the bullet … the smaller the area that defines good shot placement.

    2. avatar Gov. William J. Le Petomane says:

      The flip side is recoil. If you take the same bullet and increase it’s speed it’s energy will increase exponentially. However the recoil increases even more. I was looking at a table from Chuck Hawks the other day and although the rifle weights varied, when I could find apples to compare with apples it worked that way every time. Even comparing.308 to .30-06, the -06 had 7% more muzzle energy and 16% more recoil.

      Life is full of compromises.

      1. avatar int19h says:

        >> If you take the same bullet and increase it’s speed it’s energy will increase exponentially.

        Not exponentially, quadratically.

        Exponential is a^x.

        Quadratic is a*x^2.

        As for felt recoil, it increases with both bullet velocity and bullet mass, but more so with mass. In other words, if the same two rounds have identical muzzle energy, but one is lighter (and hence faster) and the other one is heavier (and hence slower), the latter will have more perceived recoil.

        This is because felt recoil is proportional to the imparted velocity of the firearm as it slams into your shoulder, and that, in turn, is guided by conservation of momentum. Momentum is mass by velocity, so the equation looks like this:

        Mgun * Vgun = Mbullet * Vbullet

        or

        Vgun = (Mbullet * Vbullet) / Mgun.

        On the other hand, muzzle energy is 1/2 mass by velocity squared:

        Ebullet = (Mbullet * Vbullet^2) / 2

        So if you increase bullet mass 2x, the recoil velocity of your gun also increases 2x, and your muzzle energy increases 2x. But if you increase bullet velocity 2x, the recoil also increases 2x, but muzzle energy increases 4x.

        (Note that there is a distinction between recoil velocity and recoil energy. The above is all about recoil velocity. However, for felt recoil, that is the most important metric, because it’s what makes said recoil “snappy” rather than “pushing”.)

        This is exactly why calibers got smaller and smaller over time – if you can increase velocity at the same time, you can get the same muzzle energy, but with reduced felt recoil (and hence more control in full auto). It’s also why the heavier the gun is, the less it recoils, all else being equal.

        But, of course, reducing the bullet diameter means reducing the wound channel, so you have to start relying on expansion, tumbling or fragmentation to ensure that all bullet energy actually gets dumped into the target. Also, faster bullets require longer barrels.

        1. avatar Gov. William J Le Petomane says:

          Yes, quadratically. Sorry, I flunked out of algebra. If you double the speed of anything (bullet, car, wind, whatever) the energy increases by 4x, not 2x. Quadruple the speed and you increase energy by 16x. This is why tornadoes are so nasty. It also requires 4x the energy to accelerate a bullet to twice the speed.

          I looked back at that recoil table and it does seem that recoil velocity are much more in line with muzzle energy. Still there’s no getting around the fact that hitting a target harder means enduring more recoil. Everyone has their own threshold.

    3. avatar mark s. says:

      As a younger man I preferred mass over velocity , then I gradually grew into a full out velocity guy .
      Evolution of Species .

  22. avatar Ed Rogers says:

    Where does this figure into my 5.7 weapons??

    1. avatar DJ says:

      They’re all spending less than you for ammo. 🙂

  23. avatar other chris says:

    Here’s my plug for the Grendel rounds. Good balance of projectile size and velocity considering the massive limits of the ar15 magwell. I think 6.5, 7mm, and .270 provide a really nice balance of performance in terms of terminal and flight characteristics.

  24. avatar HiddenHills says:

    An AR is easier to operate at high mall-speed on a Segway scooter. The longer length barrels of a .308 are more prone to impinge on support columns, although the .308 will better penetrate perp’s Segway. Operators gotta operate operationally, you know.

  25. avatar W says:

    “Their lethality is based entirely on how powerful they are. 5.56 is only half as powerful as the 7.62 NATO (.308) hunting bullet.”

    The critical element is what the bullet actually hits. We don’t like to admit it, but it’s some part marksmanship and some part luck. We’d prefer to think that if we only used [insert your favorite caliber here], the bullet would do the work and marksmanship and luck would go away. But, it’s not like that.

    If one doesn’t like the story below, then I would recommend that they read a few Medal of Honor narratives.

    http://www.ammoland.com/2013/06/firearm-stopping-power-fact-fiction-and-anecdotes/#axzz4ALrxPYK6

    “Massad cites the following incident: NYPD, having reason to believe that a certain store was going to be held up, planted a shotgun-armed officer in a concealed position in the store. When a robber entered the store and pointed a handgun at the proprietor, the officer appeared from hiding and ordered him to drop the gun. Instead he turned thereby pointing his gun at the officer from a sideways position. The officer fired and the 12 gauge slug entered the robber’s body through the arm pit, transited his chest (missing the heart) and exited from his other armpit breaking his arm. The robber got back up and ran two blocks, stopping only when the pursuing officer tackled him from behind. Incidentally, the robber survived.”

  26. avatar Juice says:

    Mr. Sullivan’s point can be gleaned from reading the article on thefederalist. The uniformed militaries of the world restrict themselves to non expanding bullets, so they designed a rifle that could shoot a lot of small, very fast fmj bullets in a controlled manner that would tumble instead of punching holes and that you could carry a lot of ammo for. Most civilians of the U.S. may use non-select-fire rifles with expanding bullets, and are required to do so while hunting in many instances.

    So, in 1960, he did not predict the wide popularity of the AR. If he had, he would likely be a much wealthier man.

  27. avatar Benzo says:

    I have a deeply personal caliber war every time I get a few extra bucks to spend on ammo. Which caliber this time?

  28. avatar jwm says:

    Meh, I split the difference and got a .243.

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