at what velocity does a 5.56 have to be at to fragment in soft tissue to cause the big wound cavity?

5000 fps will do for sure.
GG

It has to be at 2700 fps for the projectile to fragment RELIABLY.  It will still fragment at velocity as low as 2500 fps, but not very reliably.

The fragmentation mechanics are also different at different velocities.  Let's see if I still remember this correctly:

Above 2700 fps: multiple fragmentations below the cannelure

2500 fps - 2700 fps: the projectile will fragment into two large pieces under the cannelure

Below 2500 fps: no fragmentation or very unreliable fragmentation, but the bullet will still yaw.

Correct me if I am wrong on this, anybody!

Cheers!

Johannes

You left out the part about how you have to shoot the bad guy in the abdomen or the thighs to have enough tissue density and thickness to provide conditions that promote fragmentation upon the yawing of the bullet.

Quoted: You left out the part about how you have to shoot the bad guy in the abdomen or the thighs to have enough tissue density and thickness to provide conditions that promote fragmentation upon the yawing of the bullet.

Damn, finally someone that has placed some thought into this topic... Good Job Dave !!!!  The most efficient stopper is a thoraic (lower throat) toward middle chest cavity hit.  Only problem is that this area has many air voids (lung matter) that produce a very low density media for terminal ballastics.

Now, let's carry this thought one step further... Then, you will see why a varmint load such as V-Max will make a excellent self-defense load.

And for you Politically Correct people, there is even the Hornady TAP Law Enforcement ammo that the average Joe can purchase.  The TAP ammo is really varmint V-Max ammo repackaged.  You can tell the court that you used the same stuff that the Law establishmnet uses.

Did this a couple weeks ago.
35gr V-Max in front of 25gr of AA2200 into a gallon jug of water, small entry hole, the jug split into 3 large pieces & there was NO exit hole!!

Same load into a large pumpkin filled with water, entry hole was the size of about 1/3 of the pumpkin & parts of it blew back towards me 8 feet, NO exit hole!! Very cool!!!!!

ColtShorty

GOA KABA COA JPFO SAF NRA

"I won't be wronged,  I won't be insulted
and I won't be laid a hand on. I don't do
these things to other people and I require
the same from them."

Dave G is correct, you do have to have substantial tissue density for the fragmentation effect to take place.  If you hit organs with low tissue density (i.e. lungs that is full of air pockets) you would most likely create a clean small hole.  I would think, however, that if the projectile happened to hit a rib cage or sternum, the projectile would yaw and fragment.

I still would like to have the fragmentation capability, however, just in case that I did hit my enemy in the gut or tigh, I would still have a better chance of incapacitating him or demoralize him and nullify his will to fight.  I heard there is nothing worse than bleeding all over yourself with severe stomach pain.

Keep in mind, tho, that hoping (or worse expecting) your enemy to seize fighting only because you shot him in the gut or in the tigh is probably the fastest way to get you killed in combat.  

Since I live in the good ole' USA (instead of West Bank or Afghanistan), however, my combat experience will be limited to fights against water jugs, beer cans, and bulls eye paper targets.  Sigh, life is such a bore here in great old USA!

Cheers!

Johannes

at what range did you blow up the pumkin and jug?

Shooting a jug full of water was one of the things people did, thinking that since people were mostly water, that shooting a jug of water would duplicate bullet performance in people.  

Wrong...Real splashy, but not a realistic demonstration of potential bullet performance.

Many people who have survived being shot have reported feeling little or no pain until some time later.  Many reported feeling dull pain or like they had just been punched.  Many people who were shot and died later didn't show much pain either.  Then they fell over and died...later, from blood loss.  

You want to stop a bad guy right now?  Hit the Central Nervous System...Brain Housing Group and Spine.  The heart is a close second.  Punch a hole in it and bleed 'em out.  Takes a bit longer to drop him, though.

Or you could join the yaw and fragment, bloody big hole in the gut or butt crowd and be snickered at by those who know how to read AND comprehend.

Quoted: at what range did you blow up the pumkin and jug?

About 15 yards.

ColtShorty

GOA KABA COA JPFO SAF NRA

"I won't be wronged,  I won't be insulted
and I won't be laid a hand on. I don't do
these things to other people and I require
the same from them."

So next time we are attacked by 2 litre jugs of Jello, wait until they close to within 50 yards...right?

Is that green Jello...red...which?