body mass needed to make 5.56 tumble and break up.

[Come and take it.]

I shot a small predator recently with a mini-14 using ball ammo. After several hits it still reacted like it was never shot and ran some distance before I anchored it with a critical hit in the nervous system.

How much tissue is required before one can benefit from the infamous tumble and break up.

Also why doesnt hydrostatic shock take place on same target? Does hydrostatic shock also have to rely on bullet expansion or breakup?

 

[Art Eatman]

The only ball ammo I ever used was the early stuff, which at close range seemed to blow up just like soft points. SFAIK, any notable hydrostatic effect pretty much depends on the bullet opening up a good bit or by blowing up, and even then it's localized. But even a solid bullet makes some amount of wound cavity inside an animal.

It seems to be consensus that hydrostatic effect is very much over-rated, FWIW. A bullet in the butt isn't gonna send a shock wave of destruction throughout the animal.

 

[Bartholomew Roberts]

1. What kind of ball ammo? Not all ball ammo is the same and not all of it behaves the same way.

2. What was the distance? For ball ammo like M193 and M855, they need a velocity of at least 2,500fps and preferably 2,700fps in order to yaw and fragment.

After several hits it still reacted like it was never shot and ran some distance before I anchored it with a critical hit in the nervous system.

Yes, if you don't hit the central nervous system then even total destruction of the circulatory system may still leave enough blood pressure to keep an animal alive for some seconds afterwards (a human being for example may do 13-15 seconds). You can do a lot of physical activity in 13-15 seconds.

How much tissue is required before one can benefit from the infamous tumble and break up.

It depends on the ammunition type and the velocity. Some types (M855 for example) are notorious for variation and the neck length (distance the bullet travels before it begins to tumble) can be anywhere from 2-9". Your individual rifle barrel also plays a role in this (a phenomenon called "fleet yaw") and the same ammo that travels 9" before yaw in your barrel might travel 2" before yaw in another barrel.

Also why doesnt hydrostatic shock take place on same target?

Search the archives here, I think there was a good discussion of hydrostatic shock and the science behind the theories not too long ago.

 

[CraigC]

Use a better bullet. Unless you're making headshots, ball ammo is virtually worthless on game, from 9mm up to, well, anything. If you're shooting game, use a game bullet. Save the FMJ's for range time.

 

[Brian Pfleuger]

Hydrostatic shock depends on the energy from the bullet being transfered to the target.

In other words, expansion. At least for small bullets.

 

[GeauxTide]

+1 Peet

SP/HP put the hydro in hydroshock.

 

[Come and take it.]

Usually I always use expanding ammunition but I was temporarily encouraged by claims that ball could work on game.

I normally use Winchester 45 grain JHP on game.

I was using Winchester 55 grain FMJ during this instance.

 

[Alleykat]

It's silly and foolish to depend on the haphazard breaking apart @ the cannelure of ball ammo, regardless of the velocity. It's always haphazard. However, when shot into flesh of sufficient mass, most .223 ball bullets will tumble, making a grievous wound channel. Fragmentation is not necessary for lethality.

 

[hammie]

I think the infamous bullet tumbling effect is primarily dependent on barrel twist and muzzle velocity (and of course bullet weight and diameter). Eugene Stoner originally designed the AR-15 for a 1 in 14 twist, which would marginally stabilize a 55 grain bullet in air. If it entered a denser medium, it would become unstable and could tumble The tumbling effect would give increased stopping power. (The old british revolver service cartridge, essentially a .38 smith & wesson with a 200 grain bullet, utilized an understabilized bullet and gave better stopping performance than its caliber and velocity would warrant.)

When the AR-15 was adopted as a service rifle, the military opted for a faster twist, because they wanted to be sure of accuracy at longer ranges. The military later became disappointed in the penetration of the 5.45 mm and changed to a heavier bullet with an even faster twist rate. I think older mini 14's had a 1 in 10 twist and later ones had a 1 in 7 twist. At either of those twist rates, you shouldn't see any bullet tumbling, even in a denser balistic medium.

 

[Scorch]

On small animals, using ball ammo, you pretty much need to hit a bone to see any seriously horrendous damage. If you do hit a bone, it can get pretty gruesome, but otherwise it just drills right through them and leaves a neat little hole, that's why a lot of fur hunters love FMJ bullets. One problem with that is the animal will run until it drops 1/2 mile away. Me, I like a 55 gr SP at about 3900 fps. The hole's not so neat after that, and they drop where they stand.

BTW, the early M16s had a 1:12" twist. The tumbling effect was not planned or necessarily desirable, but it got a lot of press (not all of it true). But I can tell you that they work very well.

 

[jammin1237]

hydrostatic shock has very little to do with bullet expansion, it is more dependent on velocity, bullet weight, and ogive shape(the angle of the conical shape of the front of the bullet) going through soft tissue... take a 55gr long ogive .22 cal at 3500 feet per second will be "capable" of transferring about 1495 ft-lbs of energy to the target "if" it expands and transfers all its energy and doesnt go through the target...

now take a 250 gr .45 cal with an abrupt ogive moving at 1625 fps will give approx 1465 ft-lbs of energy and be able to transfer more shock to the target just because of its momentum and shape...

just food for the grey matter

cheers

 

[L_Killkenny]

Here's a couple thoughts...

Don't use cheap ball ammo for hunting and .....

STOP TAKING BAD SHOTS!

You make a series of lousy shots and excect the coyote to die right there?
Geez!

LK

 

[Bartholomew Roberts]

I was using Winchester 55 grain FMJ during this instance.

Which Winchester 55gr FMJ? It isn't all the same quality there either. You are looking for Winchester Q3131 or Q3131A if you want to duplicate the military 55gr loading (M193).

Keep in mind though that even under perfect conditions (2,700fps +) M193 fails to yaw and fragment about 25% of the time.

I think the infamous bullet tumbling effect is primarily dependent on barrel twist and muzzle velocity (and of course bullet weight and diameter). Eugene Stoner originally designed the AR-15 for a 1 in 14 twist, which would marginally stabilize a 55 grain bullet in air. If it entered a denser medium, it would become unstable and could tumble The tumbling effect would give increased stopping power.

This is a myth and has no basis in science. Flesh is so much denser than air that ANY spitzer bullet in any caliber will eventually tumble after it hits flesh. Changing the twist to 1;12, 1:9, 1:7, etc. has absolutely no effect on the bullet's stability in a mostly liquid medium like tissue; because none of those twists are nowhere near what is necessary to stabilize a bullet in flesh.

 

[impalacustom]

That is why it's illegal to hunt here in many states with FMJ. Use the right weapon and bullet for the right situation.

 

[Swampghost]

BM does make a difference.

F'instance, a friend is going hunting in Africa and buys an H&H for taking out Cape Buff's, Rhino's, etc. For practice he shoots Armadillo's in his pasture with solid brass bullets and the little dudes just waddle off like nothing happened. Obviously they didn't waddle too far but they kept on going.

Here's what you get when shooting deer (our smaller version) with a .44 Mag., these are Rem. 240 gr. JHP's at swamp range. The one in the lower right is my favorite, it hit a rib dead center. Note the expansion.

I switched to CA solids to try to minimize the damage and not having to pick all of these pieces out of the meat! I have yet to test my theory as I only got out for one day last year due to a personal injury and taking care of Mom.

She passed Feb. 2. I only missed a season and will always remember the time spent with her in her final days.

IMHO a .44 cal. through and through or even stopping will beat a smaller round that has to open up to that cal. AFTER penetrating. I'll post when I have some results.

 

[Malamute]

I've shot small game with 5.56 M-193 loads. The results were erratic. Sometimes the critters were all crunchy, and stopped DRT, sometimes they weren't. One jack rabbit took a chest hit @ 20 yards from an early SP1 Colt rifle and got up and ran off while I was reloading the mag. Soft point loads are an entirely different matter. DRT on anything I shot with them up to coyotes, with good size exit holes. Cottontails experience a compromise of integrity when hit with .223 SP loads.

A friend shot a deer with a mini and 55 gr SP loads. Bad idea. He tracked it over a mile. I helped butcher it, only tiny pieces of bullet fragments. I'm cured of wanting to shoot anything other than small game or varmints with a 5.56/.223.

RN .45 acp loads arent very impressive on game either.

Keith type SWC loads make critters look like they were hit with a baseball bat at every hit, even poor ones.

 

[Alleykat]

Jammin1237: "

going through soft tissue.

"

So, what do you think "soft tissue" is made of? Of course, it's the non-compressible water in the tissue that causes expansion!!!!

 

[Come and take it.]

From what I gather I have a better chance of stopping a 300 pound man in his tracks with FMJ 5.56mm ....

Than a 100 lb malnourished geurilla fighter.

Would a deer get stopped very well by XM193? Maybe if you shot the deer frontally through the chest instead of the side?

 

[jammin1237]

i apologize Alleycat, my comment was not directed to the issue of bullet expansion, it was for how much a target would be affected by "hydrostatic shock"... if a bullet expands(most are designed to "cut" through tissue when expanded) or fragments you will lose "hydrostatic shock" value, granted it will give more tissue damage...

it is the initial entry and ability of the ogive shape that delivers the "hydro static shock wave"...

 

[Swampghost]

Here's another thought. In theory a bullet travelling at supersonic speeds is pushing an air wave ahead of it. The forward most part of this wave will penetrate a soft target prior to the bullet having actual contact with the target.