Military M-16

Olgrey

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Hopefully the members here will not consider my question too silly but recently my neighbor, who is older than I and a Vietnam vet, was heard talking to someone about the M-16 and 5.56 caliber. He was saying that the 5.56 bullet was made to tumble and create larger wounds. I remember hearing this as a teenager, but was curious to know if it is true? Also if true, what does this mean for the .223 since they are almost the same?
 
The chambering itself was not intended for that purpose. However some of the military projectiles do tumble through soft tissue and cause great havoc. There are also some that tend to separate at the canelure and cause multiple wound channels.
 
Originally Posted By: OlgreyHopefully the members here will not consider my question too silly but recently my neighbor, who is older than I and a Vietnam vet, was heard talking to someone about the M-16 and 5.56 caliber. He was saying that the 5.56 bullet was made to tumble and create larger wounds. I remember hearing this as a teenager, but was curious to know if it is true? Also if true, what does this mean for the .223 since they are almost the same?

Short answer - nothing.
 
They are talking about the 55 grain FMJ bullet used in the assembled cartridge not the caliber itself. It is against "war" rules to use any bullet design that causes undo harm to the enemy, so to cause as much destruction as possible using the FMJ type bullet, the 5.56 caliber bullet is long and thin if you will, and upon impact with soft tissue the tail end will over take the front end and cause the bullet to tumble in the body and break apart at the canelure causing two or more wound channels and a big ugly hole in the tissue as well. In war a wounded man will take an additional 7 persons to care for him, but a dead one takes away just the one.
 
I've heard that story ever since way back then too.
I've never seen anything to make me believe it was true.
I'm sure all bullets will upset and "tumble", but I've never seen any evidence that the 5.56 military ammo was "designed" to do that, and I've never seen any testing done in ballistic gel that proves that it does.
 
What FW said is a lot more reasonable if we apply what we know to be true. We have all seen target bullets pencil through and not tumble. Any bullet should penetrate in a straight line until hitting something solid, like bones, then all bets would be off.

Case in point; I shot a cull buck last year at roughly 100 yards. The deer was facing me with his head up. I shot him just below the throat patch with a 180sgk loaded to 3150fps. I expected his head to almost be removed, what I found after cleaning was 2 broken neck bones and the exit between his front legs.
 
Early M16's also had a slower twist barrel that did not stabilize the 55gn fmj as well, which often resulted in the bullet tumbling once it impacted.
 
comparing the early m16 to a modern ar15 is like comparing an engine built in the 60's to one built with modern machining tolerances today. even though its a may still be just chevy 350 v8, they're two entirely different animals.


decades of refinement have made the ar15 what it was today, and its m16 history is just that - historical background that lead to what we have today.
 
Originally Posted By: Huckleberry75Early M16's also had a slower twist barrel that did not stabilize the 55gn fmj as well, which often resulted in the bullet tumbling once it impacted.

Yep, I think it was a 1-14" twist. That seems to be where the "tumbling" deal originated.
I've even heard that the "design" caused the bullet to tumble in flight.
rolleyes.gif
 
Having a bit of experience with the M16 in Vietnam they didn't tumble for me. My job in Chu Lai was to shoot stray dogs out at the garbage dump as we had rabies problem. They just pencilled right through them, sometimes taking multiple hits to put them down unless bone was hit. Unlike the battle field I got to walk out and look at them and bury them.

In 1966 I had a factory Remington 223 in Taiwan and had unlimited access to millitary ball ammo and none tumbled in flight. I still have 14 boxes of the stuff.

I think the myth got started when folks saw the damage caused by the high speed little bullet when it hit a bone.
 
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Originally Posted By: fw707Originally Posted By: Huckleberry75Early M16's also had a slower twist barrel that did not stabilize the 55gn fmj as well, which often resulted in the bullet tumbling once it impacted.

Yep, I think it was a 1-14" twist. That seems to be where the "tumbling" deal originated.
I've even heard that the "design" caused the bullet to tumble in flight.
rolleyes.gif



It's lengthy and a complicated study... much has to do with barrel lengths of the various 5.56 rifles and carbines, impact velocities of the projectiles, engagement range of the combatants, twist rates of the barrels and yes the bullet design and construction. Some key words to research regarding bullet design and efforts to improve terminal performance of 5.56 FMJ ball ammo are "bullet yaw and fragmentation" "M855" and "open tip match MK262." Me..., I shoot a Federal or Speer bonded soft point or Barnes TSX. Problem solved!
wink.gif
 
Originally Posted By: fw707Originally Posted By: Huckleberry75Early M16's also had a slower twist barrel that did not stabilize the 55gn fmj as well, which often resulted in the bullet tumbling once it impacted.

Yep, I think it was a 1-14" twist. That seems to be where the "tumbling" deal originated.
I've even heard that the "design" caused the bullet to tumble in flight.
rolleyes.gif



LOL Really?! They'll tumble in flight too???
lol.gif


Soooo, would these be some of those "magic bullets" the Warren Commission was talking about??
scared.gif
 
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