Subsonic kill power ballistics

[eou_edu]

So I've read a lot about "kill power" of a bullet and I think I'm more confused now that I was beforehand. It seems like everyone has a different opinion on "kill power" of bullets. So what makes kill power?

First let's state the rules: 1) obviously shot placement is key (now nobody needs to comment on that now). 2) Also obviously the key is you want the bullet to enter the target, fragment inside and not leave out the other end. 3) let's say point blank range so we don't have to argue ballistic coefficient, and every caliber hitting the game at 1050 fps. 4) Finally since I'm interested in subsonic ammunition anyway and that eliminates one extra factor of kill power from the equation: velocity lets discuses that.

One end of the spectrum there is 100 grain 223 ammo to 600 grain 50 beowulf. Obvious the Beowulf has more energy. But how does energy effect "kill power?" I can see in some ways the 50 beowulf having a lot more kill power than the 223 having more energy and creating a bigger wound channel thus more likely to hit a vital organ. I can also see the 223 having an edge in some other ways. It's a much smaller bullet and therefore exerts more PSI on the hide making it more likely to penetrate the hide and not bounce off. At 1050 fps this won't be much of an issue, but maybe when the ammo slows to 500 fps or so the 223 would have more penetrating ability at same velocities.

Sorry for some question that sound like newbies. I'm am in fact one. Before 2012 the only thing I new about guns was I pointed and pulled the trigger. So it is a steep learning curve for me.

 

[TurtlePhish]

I don't think there's really any satisfactory way to answer this one way or the other. A general rule is that if it's bigger, heavier, and the same velocity, it'll hit harder.

 

[Sam1911]

There have been many attempts over the years to try and capture what you're describing as "kill power." None of them have been very useful. "Kill power" sounds like just another shot at a "Taylor Knock Out" value or Marshall and Sanow rating. Permanent wound channel, temporary stretch cavities, "hydrostatic shock," and other quantities of pixie dust all have been identified as crucial to nailing down exactly how a bullet will perform in living tissue.

Honestly, about all we can really say is "good enough" and "not good enough." Penetration is pretty well accepted as a crucial factor. But penetration is complicated. It is affected by velocity...but not consistently the way you'd think. It is affected by bullet composition, frontal area, sectional density, and sometimes pure dumb luck.

You have to pick out what kind of creature you're attempting to kill, wound, or just plain STOP, as well. A cape buffalo that's charging you? A human that's about to stab you? A white-tail deer that you don't want to destroy too much of?

Also obviously the key is you want the bullet to enter the target, fragment inside and not leave out the other end.

Not really. You want the hole to go all the way through. More paths for blood to leave the body. And if you're trying to get better penetration, it is much better if the bullet stays together than if it fragments. (But we're not ALWAYS trying for that. Some bullets expand their wounding potential through fragmentation ...complicated, eh?)

And which numbers do you choose to believe, care about, or assign importance to? Energy? Velocity? Momentum?

For someone in your situation, trying to understand what works and why, the best bet is probably to look to the true experiences of others who have shot at things A LOT and can tell you what worked when, and why they think that's so.

 

[rcmodel]

Plug in your numbers here:

http://www.handloads.com/calc/quick.asp

How much store we can put in Taylor KO values is debatable.

But given a choice?
I for one would rather be shot with a .223 at 1,050 fps then a 600 grain .50 Beowulf at 1,050 FPS!!

PS: A 600 grain bullet won't "bounce off" at 250 FPS.

rc

 

[moxie]

Recommend you search the net and get some books on "terminal ballistics."

Here's a wiki article for starters.

http://en.wikipedia.org/wiki/Terminal_ballistics

But, it would really be helpful to start with a study of exterior (or external) ballistics so you'll get an understanding of what bullets are doing before they hit the target. Two different disciplines.

 

[PapaG]

I don't remember if it was Keith or Askins that said, a big bullet that goes through is better than a small one because it lets more air in and more blood out.
I've shot my share of deer and the ones that ran the shortest distance were the ones hit in the heart, spine, or heart/lungs.
Jim Carmichael (sp?) ran a lot of data on animals that dropped at the shot..as if all the circuits were shorted out. His belief was, especially on the big ones, Cape Buff and so on, that the hit was in the "boiler room" just as the heart was filled and ready to pump the next load of blood. The bullet, hitting at that point, (and it had to be a big one) would seemingly accelerate the blood to the brain and central nervous system shutting down things already.
I've not shot anything bigger than deer or hog so cannot comment but I can find no reason to doubt the guy who was shooting editor for a major magazine for over 20 years and an accomplished shooter.
So....what is kill power. I don't think anyone knows. Cooper said that if you threw a spear through someone it would probably kill him, but not right away and maybe not soon enough to stop his agression. If you could accelerate a baseball bat and do the same, he probably would stop right now.

 

[Loosedhorse]

I haven't heard the term "kill power" before. "Stopping power," sure, but that didn't measure killing ability. Neither does the TKO (which was literally a metric of the ability of a round to "knock out" an animal--elephant, specifically).

For most hunting rounds, we want a bullet heavy enough (and tough enough) to penetrate to the animal's vital organs. That, plus good shot placement, is essential to quick, clean hunting kills.

 

[DoubleTapDrew]

Do any bullets fragment at subsonic velocity? I have heard the 55 and 62gr military ball needs to be >2700fps or so to fragment reliably but haven't researched the heavier 100gr stuff.

 

[Ken70]

"Do any bullets fragment at subsonic velocity? I have heard the 55 and 62gr military ball needs to be >2700fps or so to fragment reliably but haven't researched the heavier 100gr stuff."

If a flunky little round like a 62gr won't fragment at 2.5 times the speed of sound, I doubt if a 225gr .30 at 1000fps will do much more than drill a caliber size hole...but if you place that .30 in the right place, like the head, it doesn't need to fragment.

 

[mdauben]

1) obviously shot placement is key (now nobody needs to comment on that now).

True.

2) Also obviously the key is you want the bullet to enter the target, fragment inside and not leave out the other end.

This is very much open to debate. Hunters generaly seem to prefer bullets that will expand and pass completely through the game's body, leaving an exit wound and increasing the rate of bleeding and potential blood trail. For self defence, most people seem to prefer bullets that achieve maximum expansion without fragmenting, as long as they achieve some minimum penetration. In this case, over penetration that passes completly through the body is generally considered a bad thing, due to potentially endangering bystanders. The only place I think fragmentation might be encouraged is with FMJ military rounds, becuase they can't employ the soft- or hollow-points necessary for expansion.

3) let's say point blank range so we don't have to argue ballistic coefficient, and every caliber hitting the game at 1050 fps.

This is going to, I think artificially favor large, heavy bullets. Smaller calibers often achieve their efficency through higher velocity.

4) Finally since I'm interested in subsonic ammunition anyway and that eliminates one extra factor of kill power from the equation: velocity lets discuses that.

I'm curious as to why? Other than their advantage in suppressed (silenced) weapons, subsonic have no advantages over faster rounds, while faster rounds will have more penetration, more expansion, better ballistics and will generally be more effective overall.

 

[eou_edu]

True.


This is very much open to debate. Hunters generaly seem to prefer bullets that will expand and pass completely through the game's body, leaving an exit wound and increasing the rate of bleeding and potential blood trail. For self defence, most people seem to prefer bullets that achieve maximum expansion without fragmenting, as long as they achieve some minimum penetration. In this case, over penetration that passes completly through the body is generally considered a bad thing, due to potentially endangering bystanders. The only place I think fragmentation might be encouraged is with FMJ military rounds, becuase they can't employ the soft- or hollow-points necessary for expansion.


This is going to, I think artificially favor large, heavy bullets. Smaller calibers often achieve their efficency through higher velocity.


I'm curious as to why? Other than their advantage in suppressed (silenced) weapons, subsonic have no advantages over faster rounds, while faster rounds will have more penetration, more expansion, better ballistics and will generally be more effective overall.

Shooting with a suppressor is why I'm interested in it. When I finally decide on what gun or guns to buy this will be a big part of the decision. I want something that will shoot subsonic and supersonic, suppressed and unsurpassed. Mostly a semi auto for hog hunting. I also really like my hearing. So even when I'm elk hunting I plan to keep a suppressor on the gun for shooting supersonic. To me $1000 is a drop in the bucket to spend on a suppressor when it can save my hearing. It has a lot of other advantaged when hunting too. I also don't want to wear hearing protection for a week straight all day long in anticipation of maybe seeing an elk.

All the rest of the stuff is very interesting. I was hopeing to get a definite answer but the definite answer is there is no definite answer. It's hard to make a conclusion on anything when there isn't definite scientific data from a controlled test. Private world would never test something like that. I'm sure the miltary has at one point or another, but I'm also sure that's not a secret they want to share. So the best we can go on is personal experience. Then it's hard to make decisions based on personal experience because the experience and so many other factors vary so much. I myself used to think a 308 was a terrible caliber after I witnessed my rookie hunting buddy years ago shoot an elk twice at about 150 yards and it ran away. After 3 days of searching all we ever found was a little bit of blood and no elk. I thought this was because the 308 was a bad elk gun. Little did I know there were too many other factors that played into what happened that day. He didn't know anything about ammo, probably ended up buying target rounds, to heavy for his twist rate, gun sighted in, making a bad shot, and who knows what else.

 

[TurtlePhish]

.300BLK, my friend. It's all you'll need. Subsonic yet hits hard and it's great suppressed.

 

[eou_edu]

That's probably what I will end up buying. I'm also thinking of just a 308. I've heard with the new powder that's out, people are shooting the subsonic 308 very accurately. Plus I'd want it to shoot supersonic as well. The ballistic coefficient on the blackout isn't all that great and it's a short range gun. 308 has a very good ballistic coefficient and it's a long range gun. My other choice I might be thinking about was the 6.5 grendel. Some guys are loading them in 160 grain subsonic. The 300 blackouts are going up to 240 grain. This is what I was getting at in my original question in a round about way. I was thinking the grendel, being a shorter diameter bullet, might have more penetrating ability than the 300 blackout. The ballistic coefficient on supersonic is almost twice that of a 300 blackout and therefore might carry the bullet further subsonic in the grendel. I guess a little more research will tell.

 

[tundraotto]

I think ideally in any subsonic round you would want a max load with the heaviest bullet possible while keeping it under the speed of sound....kinda like the heaviest of the heaviest for the 45-70....slow 500+grain cast bullets penetrating 21 milkjugs in a row.....I would not worry much about BC as that is the price you pay for going subsonic...

 

[Casefull]

If the noise of a rifle is a major concern for you, getting an elk will never happen for you. That requirement would never be in the top 1000 list of an elk hunter. A subsonic round would bounce of an elk or wound it. Put some damn ear plugs in man.

 

[eou_edu]

If the noise of a rifle is a major concern for you, getting an elk will never happen for you. That requirement would never be in the top 1000 list of an elk hunter. A subsonic round would bounce of an elk or wound it. Put some damn ear plugs in man.

I think there is a slight misunderstand there. A subsonic round for elk would just be stupid, I would never do that. However A .30 caliber suppressor on a 300 win mag (shooting supersonic only), that I also use to shoot subsonic on a 300 blackout would be ideal. In a 300 win mag this would at least eliminate the need for "damn ear plugs." Which after hunting for 2 weeks, sometimes hiking 20 miles all day long, wearing ear plugs on the chance to get off one shot is a little too much. I also don't want to hassle with them if I come up on a quick shot for an elk. Not many elk hunters are concerned about their hearing, buy maybe they should be. I'm 31 and have excellent hearing and want to keep it that way. My hunting partner is also 31 and bordering on needing hearing aids. All because he shoots a 338 ultra mag with a muzzle break and no hearing protection. One blast from that gun WILL damage your hearing permanently.

In addition to that shooting supersonic through a suppressor for elk hunting has several advantages. It reduces kick like a muzzle break. Hides the muzzle flash. Also since most of your sound is gone from the muzzle you are left with the supersonic crack and Elk are unable to tell where the shot came from and in some cases will actually run right towards you after hearing the shot! For me it's a smart investment. $1000 is a lot to spend on a silencer and a tax stamp, but hearing aids aren't cheap either.

 

[mdauben]

If the noise of a rifle is a major concern for you, getting an elk will never happen for you. That requirement would never be in the top 1000 list of an elk hunter. A subsonic round would bounce of an elk or wound it. Put some damn ear plugs in man.

Actually, the US is something of an anomoly in their restrictions on civilian suppressors. In many other countries, suppressed hunting rifles are not unusual (actually, I think some of the western states in this country allow the use of suppressed hunting rifles). Now, that said I don't think they are using subsonic rounds to hunt with, but even with supersonic rounds a suppressor helps dampen the noise.

 

[MachIVshooter]

Shot placement aside, a bullet's wounding mechnism is one thing and one thing only: Destruction of tissue/organs, causing blood loss and the failure of those organs. When you remove high velocity rounds from the equation, you are pretty much limited to the mechanical wound caused by direct contact from the bullet itself. Therefore, the bigger the bullet, the bigger the wound, and the greater the damage.

Basically, because you won't be getting the massive cavitation caused by high velocity rounds, what you'll be looking for is the largest possible through-and-through wound channel.

 

[.45Guy]

Do any bullets fragment at subsonic velocity?

The CCI pre segmented subsonic hollow points seem to work rather well on tree rats.

 

[Old Time Hunter]

How well does an arrow work? Way subsonic, very efficient tool for hunting too.

Many a man has been brought down with .44-40 traveling well south of even 800 feet per second, and the prescribed weight was around 200 grains.

Whether out of a Peacemaker at 15' or a '73 Winny at 300 yards, more men, good and bad, more game, big and small, have been felled by the 44WCF than all others combined. Or so it is said.

 

[Sam1911]

Whether out of a Peacemaker at 15' or a '73 Winny at 300 yards, more men, good and bad, more game, big and small, have been felled by the 44WCF than all others combined. Or so it is said.

Considering all the wars of the 20th century -- not one of which was fought by anyone carrying a .44-40, and the most significant conflicts of the 19th century (the heyday of the .44-40's popularity) also not being fought by anyone carrying the .44-40, AND all the game felled in the 20th century by .30-30s, .30-'06s and other very popular rounds, I'd have an extremely hard time believe that statement to be even close to true.

 

[mdauben]

How well does an arrow work? Way subsonic, very efficient tool for hunting too.

Apples and oranges. Totally different wounding mechanism between an arrowhead traveling at 2-300FPS and a bullet a bullet traveling at 2-3000FPS.

 

[DoubleTapDrew]

What rifle platform are you planning on? You might have better luck getting a subsonic 300blk to cycle a semi-auto than a subsonic 308 or even .223

 

[Jason_W]

I'm a firm believer in the MATMU theory (Maximum Amount of Tissue Messed Up)

I'm no scientist, so feel free to ignore me, but it seems like the killing ability of any projectile is tied to how much vital tissue it can cut, crush rip, tear, or shred. There are likely many ways of achieving this.

Clearly, the speedy, pointy bullets kill game efficiently, as do wide, heavy, slowish, flat point bullets (when used within their range limitations).

With a sub-sonic bullet, I am inclined to wonder if a bullet that tumbles after impact would maximize tissue destruction.

 

[eou_edu]

Shot placement aside, a bullet's wounding mechnism is one thing and one thing only: Destruction of tissue/organs, causing blood loss and the failure of those organs. When you remove high velocity rounds from the equation, you are pretty much limited to the mechanical wound caused by direct contact from the bullet itself. Therefore, the bigger the bullet, the bigger the wound, and the greater the damage.

Basically, because you won't be getting the massive cavitation caused by high velocity rounds, what you'll be looking for is the largest possible through-and-through wound channel.

Thanks for the that input. To me that is really what makes the most sense. I'm a firm believer in the simplest explanation being the best. Even though the hydrostatic shock theory and several others like that seem neat, I don't think there's enough evidence to believe them.

I do however think there might be something to smaller bullets having more penetrating abilities. This might come into play when your shooting subsonic for thick skin hog hunting. Although I've never been hog hunting (but it is very future soon plans) A smaller bullet is going to produce more PSI and therefore more likely to penetrate the thick skin. As I've read some people have problems with bullets bouncing off the hide. Just like breaking a car window. Punch it as hard as you can and it probably won't break. Touch it with a hole punch and it will immediately shatter (i'm a firefighter so that is the only practical experience I have doing this.)