shock wave?

[George]

I was in the mood for some fun shooting today, so I spent a while busting milk jugs filled with water. That was fun, shooting at them offhand from 50 yards and watching them explode. I was shooting .600" balls from my flintlock smoothbore over 85 grains of 3F Goex, and even at 50 yards they jumped 10 feet in the air, showered my Jeep, 15 feet away, with water, and were pretty well shredded. Every one of them, not a single one had a simple entrance and exit hole.

Tell me again why we believe hydrostatic shock has nothing to do with the killing power of round balls from muzzleloaders....?

Spence

 

[Ken Cormier]

It don't I have not tested it with milk jugs but my 62 smoothbore sure does a heck of a job on whitetail. :2

 

[Zonie]

If you try it with a .45 or .50 caliber rifle it won't be nearly as impressive as your .62 is.

The frontal area of the ball has a lot to do with the amount of hydraulic shock the projectile creates as it enters the object.

Your .600 diameter ball has 87 percent more frontal area than a .440 diameter ball for a .45 and 50 percent more frontal area than a .490 ball for a .50.

 

[George]

Yeah, but then the smaller balls usually travel at greater velocity, which should tend to compensate for that difference in frontal area. Actually, in my experience, the smaller balls tend to cause more tissue damage if you push them to their upper velocity range, so maybe velocity contributes more than frontal area.

Spence

 

[Dean2]

Hydrostatic shock is caused by the pressure wave moving through tissue with blood and other fluids actually flowing through it. The higher the velocity the further the shock zone extends from the bullet hole.

While all projectiles cause some hydrostatic shock the dramatic and very large bloodshot areas that extend well away from the bullet hole is usually only seen with projectiles travelling over 2500 fps. These high velocity hits will often cause the target to drop on the spot, despite the bullet entering in a less than ideal location. Large, slower moving projectiles don't usually have this same effect but they too create hydrostatic shock.

 

[Loyalist Dave]

Tell me again why we believe hydrostatic shock has nothing to do with the killing power of round balls from muzzleloaders....?

Because mamals are not milk jugs.

With the milk jug you are talking about one large chamber of nothing but liquid... when you are talking about mamals you have layers of tissues of various densities with connecting tissues that alter how the wave (if formed) moves through the target, and what amount of damage, if any, is sustained. Internal tissues have some elastic qualities. Thus you don't get a very reliable result until the impact velocity is as mentioned, at 2500 fps or higher.

LD

 

[George]

I think you'd be surprised how much an animal is like solid water, especially in areas which don't involve the lung. Air is easily compressed and acts like a pressure regulator, whereas liquid filled tissues don't/can't compress, so they allow any shock wave to continue. You can easily see the difference even in the milk jugs. I made certain the jugs were completely filled, not even a small bubble of air left, because if you don't you are more likely to get a hole punched through instead of that nice explosion. The shock wave is dampened by the air.

Something which isn't readily obvious is that not all bloodshot tissue has been directly damaged. Blood coming from a simple broken blood vessel, especially an artery, can get between tissue layers and travel for long distances form the actual wound.

Where does the figure of 2500 fps come from which you guys are mentioning?

Spence

 

[Rifleman1776]

Tell me again why we believe hydrostatic shock has nothing to do with the killing power of round balls from muzzleloaders....?

Because deer cannot spell 'hydrostatic shock'. :shocked2:
And many folks want to believe what they want to belive and don't let facts get in their way.

 

[Larry Pletcher]

I want to try a variation of your experiment. I will set 6 jugs in a row and want to recover the ball. A friend recovered a center fire bullet in the sixth jug. I want to compare a .54 round ball's performance using the same number of jugs.

A very unusual thing happened in my friend's test, but it doesn't belong on a ML forum.
Regards,
Pletch

 

[Col. Batguano]

It might be somewhat interesting to try the same science experiment with a balloon blown up in the middle of the jug of water. That would simulate lungs.

 

[okawbow]

I have personal experience on the effect on similar sized deer, at the same 40 yard range with a 180 grain 2f maximum load round ball, 62 (in a heavy barreled Hawken type rifle) compared to a 80 grain 2f load 62 (in a smooth rifle). Both deer were shot through the shoulder blades without hitting the leg bones.
The buck shot with the max load went down on the spot. The ball flattened, and was recovered under the skin on the far shoulder. The wound channel and tissue damage was tremendous. Both shoulders were bloodshot and little meat was usable.
The buck shot with the 80 grain load, ran 100 yards, and out of my sight into thick brush. The round ball made a .62 cal hole all the way through both shoulders, and out the far side. There was little meat loss from bloodshot meat.

I think the fact that the higher velocity ball flattened and expanded, had a great deal to do with the increased damage and "knock down" effect on the 1st deer. The .62" ball expanded to over 1.00" and expended all its' energy in the deer. The lower velocity ball didn't expand at all, and wasted much energy on the hillside beyond the deer.

Obviously, the maximum load in such a large caliber is very hard on the shooter and rifle, but if I really needed to stop a charging grizzly, I'd want the heaviest load I could handle.

 

[Billnpatti]

Hydrostatic shock is a reality. The effect is a function of the kinetic energy and the depth of penetration. A study done by Courtney and Courtney showed that the magnitude of the hydrostatic shock wave is proportional to the bullet's kinetic enegry divided by the depth of penetration. This study was done with pistol bullets which would have MVs similar to those of a muzzleloading rifle. The effects would be expected to be similar. The next question is how much of the death of an animal is due to hydrostatic shock and how much is due to tissue damage. If one was to shoot an animal in the head, hydrostatic shock would play an extremely small part in the animal's demise. On ther other hand, a hit in an area of dense vital tissue, hydrostatic shock would play a much larger role. In any case, hydrostatic shock is a reality.

 

[George]

I want to try a variation of your experiment. I will set 6 jugs in a row and want to recover the ball.

No experiment is any good without a control. :haha: Here's what they look like when shot one at time.



I'll be glad to see the performance of a .54. I've seen the videos posted by duelist1954 and others, but I believe those were done with pistols/revolvers.

Spence

 

[George]

The next question is how much of the death of an animal is due to hydrostatic shock and how much is due to tissue damage.

That's what I think is important to get straight, the relationship of the shock wave and tissue damage. Some people seem to believe that if the bullet is traveling fast enough it will generate a lethal shock wave with even a poorly placed shot, shoot them in the knee and the shock wave travels through the whole critter and stops the heart. That seems very far fetched, to me, but I do believe there is a shock wave which causes more damage than that caused by the simple passage of the ball. As Dave said, tissues are elastic, but they can only stretch so far. We've all seen those videos or pictures of the big cavity formed in a gel block as a bullet passes through, and I believe the same thing happens in an animal. If that cavity is large enough, and blood vessels are caught up in it, they can be broken even if they aren't hit by the ball. So, the way I see it, a zone of damage larger than the ball results from that hydrostatic shock wave. Not at a distance, but locally, right along the path of the ball. That may not drop it in its tracks from the shock, but it could mean it bleeds out quicker. I know of nothing which would prevent that happening to some degree at even pretty low velocities.

Spence

 

[Loyalist Dave]

Actually it's not the surprise at how much of a mamal is water, the surprise is how little different densities of tissue need to be present to defeat the predicted damage due to hydrolic compression. :shocked2: Apparently there are a lot of things messing with the shock wave in a living body.

The 2500 fps figure I got from an Army forensic pathology lecture in the 1990's concerning bullet wounds. Some of us LEO's were allowed to attend.

I also read a paper that drops that figure to half, saying that for any hydrostatic shock the impact speed must be supersonic, and needs a bit more velocity to not drop below supersonic while passing through the target body... so say 1250 fps at impact... and when the projectile drops below that only the tissues damaged by the projectile body are affected. However, evidence in that paper of the presence of hydrostatic shock did not continue to say that evidence, i.e. bruising, had caused any substantial damage that contributed to the person or the animal's death.

That 2500 fps speed is looking pretty well established...

So far it looks like us slow moving, heavy, soft projectile folks are going to have to settle for actual damage to do the job...

In the past dozen years it's worked for me! :grin:


LD

 

[George]

So far it looks like us slow moving, heavy, soft projectile folks are going to have to settle for actual damage to do the job...

How do my jugs fit into that scenario?

If I had shot empty jugs do you think they would have blown up that way?

I should have listened to my own advice and shot a control. :haha:

Spence

 

[F.G. Ford]

One thing I have noticed, every time I take out my .75 cal., Everything lays down and disappears :bull:
I don't even need hydra...hydra...hydra...electric shock or whatever. More :bull:
Fred

 

[BrownBear]

I get a little different outcome shooting into a different medium.

In my case I typically shoot into a 5-gallon bucket filled with sand. Target taped on the side, it makes a dandy ball trap for recovering lead and recasting.

No matter what I've shot however fast (including 180 grain 30-06 at 50 yards), nothing has ever succeeded in fully penetrating the bucket.

Hit it with any round ball up to 54 cal at any velocity, and results are downright polite. Other than the hole in the target, you would think I missed the bucket.

Hit it with a 58 cal ball launched with 80 grains of powder and it's still polite. But 90 grains gives you a little geyser of sand out the top, and the geysers grow fast as you go up the charge scale.

Hit it with a 62 cal ball launched by 100 grains of powder, and you get a geyser about 3' high and have to replenish the sand every half dozen shots or so. Hit it with the same 62 cal ball launched by 140 grains of powder and you can refill the bucket every other shot. Meanwhile the bucket rocks back sharply with each hit.

Even on top of 140 grains of powder that 62 cal ball is going lots slower than a 54 cal on top of 100 grains. But man, the bucket sure knows the difference.

No answer for the hydrostatic pondering unless you want to compare sand-o-static results by measuring the geysers. But it's clear that lots more is going on with the bigger balls, lower velocity or not.

 

[roundball]

"...it's clear that lots more is going on with the bigger balls, lower velocity or not..."

Whompability.

 

[Patocazador]

Air is easily compressed and acts like a pressure regulator, whereas liquid filled tissues don't/can't compress, so they allow any shock wave to continue.

Spence

This point was really brought home to me during a Jr. college Physics class. The professor produced an old-time glass quart-sized milk bottle. He filled it to the brim with water and sealed it. He then proceeded to use the milk bottle as a hammer and he beat a 16-penny nail through a piece of 4"x4" lumber. He then broke the seal on the bottle letting a bubble of air in and then resealed it. The first whack on the nail shattered the bottle.

Liquids ARE incompressible! I've seen it.