M16A1 tumbling bullet

those of you who insist that bullets do not tumble in the air, you watch to many war movies and dont understand what tumbling really is. if they dont tumble in the air, why do we need rifling in our rifles? to stabilize the bullet....ding ding we have a winner. so, as the bullet exits the gun it spins(like a top) and as it slows down, the back which is will not slow down as fast as the front because its heavier and has less drag, it will create a wobble(like a top does as it slows down) and as the bullet travels farther away from the barrel and slows down(alot more than 10m) the becomes greater. if your shooting long range do you use boattail style bullets, yes cause they create less drag, therefore improving efficiency.

id say if you where shooting a heaver person "puffy" and you were aiming at a specific vital point and you hit the fat it would tumble and go off course.

Ok, when I was in the Marines, back in the early 80's the M16a1 came out. in boot camp we were told the rounds travel about 460 yards before tumbling begins, that's why, at the time, we shot 500 yards at man silhouettes and the object was to put the round in the belly. The reasoning, (at the time) was because a tumbling round would tear up the belly and need 2 people to remove the one wounded combatant. so, in effect one round takes 3 people off the battle field.

Whether this is still true or was true at the time, I do not know. That was the way we were trained. All I know is I cannot hit anything at less than 500 yards, 200 and 300, I suck, 500 Plus, I got ya!!!

bs on SO many levels, dude. No, bullets do not tumble in the air, if fired thru a barrel that adequately stabilizes them. Once a bullet tumbles, it has no accuracy at all, if it tumbles right out of the barrel, you can't reliably hit a man at a lousy 20 ft with it, I am not kidding or mistaken, either. If you can't hit at 200 yds, you certainly can't hit at 500 yds. A tumbling bullet has very little penetration, especially out at ranges where it has very little power remaining to it, as is the case with the 223 at 500 yds, with normal ammo, at least.

No, a fat person does not deflect the bullet, fat is easily pierced, even at very long yardages, by something as needle-like as the pointed, small diameter 223 military bullet.

The M16 was military issue as of 1968, the A3 upgrade came out in 85 or so, with the 1 in 7 rifling twist, for use with the new tracer that was created to match the slightly different trajectory of the new ball rd, the 62 gr, steel tipped type. 1 in 9 is the right twist for the 62 gr bullet, but tracers are much longer, due to the lightweight of the phosphorus core. A longer bullet requires a faster rate of twist in order to be stabilized in flight.

reply to post by BlackWidow23


I've never really gotten into a debate on the merits of 5.56 ammo here at ATS...
there are a few people who would understand but for the most part not...
still this graphic might help you understand some of what's going on ballistically


[atsimg]http://files.abovetopsecret.com/images/member/cc2d2a9d8924.jpg[/atsimg]

FYI the "Tumbling" round you talk of... was banned quite some time ago... they claimed it was cruel and inhuman...

You need a bullet that causes enough damage to take the enemy out of action.

The 5.56 in all bullet weights does that plus due to the high velocity at shorter ranges it causes a lot of dead tissue around the wound track that requires debridement and corrective surgery.

Without the debridement of dead tissue minor wounds can easily become fatal due to infection.

no, the tumbling bullet was NOT "banned', either. Where do you guys get this bs, anyway? We are not constrained to the use of fmj bullets, anyway. We can use the brilliantly effective Nosler Partition softpoint, either in our own handloads, or in ammo loaded by Black Hills Ammo Company. The 60 gr Partitition is intended for use on deer, getting 2-3x as deep penetration in flesh as the typical varmint type hp or sp normally loaded in 223 ammo. The Partition makes the 223 as least as effective as 308 ball, which is so poora performer that it's illegal for use on deer in almost every state in the US. This is the case because it just pokes a .30 cal hole in the animals, letting them run 1/4 mile or so before they bleed out and die.

Originally posted by soldierman29
...the bullets do "tumbl"e before hitting an object, its plain physics. a persons reaction after getting shot depends on alot of factors not just bullet size.

...even better statistic, 99.999 percent of bullets shot at the enemy dont even hit the enemy so it doesnt really matter what they do out the barrel if there not hitting there target.

The "tumble" effect does not occur "before hitting an object" but occurs within soft targets such as that of flesh or ballistics gel etc if it has high enough velocity upon impact.

On that 99.999 percent "statistic", do you have a source for that one? That "statistic" sounds more like a bad personal guess that may represent your particular shooting success and not an accurate representation of the average soldier in combat. So source please.

Lot of confusion and BS in here, though a few people get it right.

Bullets are spun so that they are gyroscopically stabilized in flight. This reduces drag and keeps it radially symmetrical across the front of the bullet. Exactly like throwing a football.

When a bullet encounters a resistant medium without having been stabilized, or if (typically the case) it loses its stabilizing spin, then it will behave like any other object encountering resistance, and it will pitch over (tumble) so that the heavy end faces the direction of travel. What's actually happening there is that drag is affecting the entire bullet but the heavier end has more inertia or something to power through it. Exactly like dropping a half-full shampoo bottle off a roof; the full end will always land first, having pitched over in flight.

All boattail (rear heavier than the front) bullets tumble to reverse themselves when they lose spin and encounter heavy resistance (specifically, tissue).

Some .223 and 5.56 rounds are unusual in that they are very lightweight and weakly constucted, and move extremely fast for their size. As a result, when they enter tissue and begin to pitch over, the bullet cannot handle the stresses involved and falls apart, with the parts going several different directions still at high speed.

That's what causes large wound cavities from M193 where a .308 would put a much thinner line through the target (though again with a wider tunnel in the middle where the bullet is temporarily sideways).

M855, as discussed, does not necessarily share this fragmenting characteristic, and is thus a poor choice for unarmored targets.

There's a new bullet being fielded with two-part construction designed to have both the weakness/fragmentation of M193 with the penetration of M855, but I haven't heard much about it yet.

Are you referring to the MK318 Mod 0 bullet, JBlitzen?

It's a 62 grain, open tip match, rear penetrating round, currently in use by the USMC to replace the M855 green tip penetrating bullet. It's velocity from an M-4 is around 2900-3100 FPS, methinks. The back end of the MK318 Mod 0 bullet is solid Copper that penetrates barriers like windshields and such without veering off course.

The bullet also has the cannelure that causes the front portion to violently fragment in soft tissue, (if I remember this correctly).
In order to achieve the fragmentation action, the bullet needs to be traveling around 2700 FPS. That seems to be the velocity threshold for fragmentation.

Sounds right, yeah.

You're asking a question like this on the completely wrong forum, bro. 99% of posters on this forum do not know jack about firearms and/or ballistics.

Nearly all rifle cartridges will fragment and/or tumble to a certain extent. The AK74's 5.45 round is designed more around tumbling whereas the AR15's 5.56 round is meant to fragment. If a bullet is not stabilized it can cause horrible wound channels but accuracy and penetration will suffer.

Chances are, whatever you've heard about the 223/5.56 round being "under powered" is not true. You can cause a bullet to 'destabilize' by shooting a heavy grain bullet through a barrel that it's not meant to be. For instance, a 75gr bullet being fired through a 1/9 twist commercial spec barrel is not going to be stabilized very well at all. Shooting that same 75gr round through a 1/7 twist is going to stabilize it perfectly which will greatly enhance the accuracy and penetration.

If a bullet is not stabilized well then it's not going to perform as it was meant to. It can obviously cause some horrible wound channels for obvious reasons but can be easily deflected by brush, etc.