The super destructive tumbling boolit. myth?

[MBTcustom]

My dad has always told me that a solid lead boolit is so destructive, especially in larger calibers, because after it hits it tumbles end over end, but none of my tests have ever shown this to happen. However limited my tests are, I have never seen anything but solid expansion and strait flight. Is tumbling a myth? or is it limited to certain boolit designs or what?

[Love Life]

It is not a myth. It depends on boolit design and profile. Also it depends on chance as well. However a boolit with a lighter, thinner nose and a heavier thicker base is more likely to yaw and tumble than the good ol' WFN which has much better weight distribution.

Then again I have seen FMJ boattails sail right through a soft target without tumbling. So here is what we have:

1. Boolit/bullet design
2. Chance

[MBTcustom]

He said that is why he always keeps his semi-wadcutters loaded for self defence.

[Reload3006]

Whether it tumbles or not it pancakes and I have several recovered to convince me .. the softer lead the better. It may go in .429 but its coming out almost 2" thats a big hole tumbling or not.

[Love Life]

Whether it tumbles or not it pancakes and I have several recovered to convince me .. the softer lead the better. It may go in .429 but its coming out almost 2" thats a big hole tumbling or not.

Yep. I have recently started experimenting with really soft boolits and a PB gas check in the 357 mag. Good things are happening so far.

One of the main reasons for the tumbling of the spire point is once it enters a fluid medium the lighter nos slows down faster than the heavier base. In theory, and practice, this is what causes the tumblin and sometimes shredding of these boolits. Now these are FMJ bullets and not hollowpoint or open tip.

Now a boolit that comes tumbling out of the barrel will tumble in the fluid as well. Or the FNJ will just drill a straight hole. It's a wild card.

[mpmarty]

In 1974 the Russians developed a small caliber assault rifle cartridge the 5.45 and it used a bullet with a hollow nose to increase tumbling. According to the Afgans who encountered it they called it the "poison bullet".

[1Shirt]

A lot of the bullet tumbling stories came out of the early M-16 time frame, early in the Viet Nam war. I had access to a lot of the early 5.56 mil ball ammo, and a number of the very early M-16's that were AF issue. I did a lot of testing with mil 223 ball ammo in a 722 Rem. that I had rechambered from 222 at that time. It had a 24" BBL and was a very accurate rifle. I show a lot of things and saw both straight thrus and key holes after passage thru some targets like vegatables, matting, etc. I did not keep records, so it is just my recollection.

To agree with Love Life, it is bullet/bullet design, chance, etc. what the blt impacts on, at what vol, and all in all is a **** shoot. Have seen straight thru hits on human flesh that were 22 in and just about 22 out. But they didn't hit bone. I THINK, that if a full metal jacket 22 cal blt hits bone, some form of tumbling or what ever you want to call it will occur. Hitting bone dead center, it may pass thru on straight, but I tend to doubt it. Hitting bone on a slight angle to the bone I THINK may/probably does act like most blts do when hitting brush/twigs, ect, and that is to deflect. Deflection could/probably would be considered tumbling. \

Regardless, it was with the early M-16's and the early ammo a **** shoot. Can't relate to current M-16 ammo with heavier blts and faster twists, but THINK it probably has less of a tendancy to "tumble". Just my opinion.
1Shirt!:coffeecom

[Lonegun1894]

1Shirt,
I have seen the modern M-16A2s firing 62gr FMJs, and those tend to drill straight through and have little to no effect unless they break bones or CNS. Now if you fire the same rifle with the issue 1:7 twist with a 75/77/80gr HPBT bullet, it is much more likely to be effective and seems to impress the target more.

Werent the original ealry M-16s 1:12" or 1:14" twist? If so, it would seem like the current 1:7" twist is TOO STABLE and less likely to tumble. I have talked to some Vietnam vets who were in during the transition from the slow to the fast twist and most complained about the faster twist being too fast and making an inefficient caliber even worse. Makes me think the perfect small-caliber combination would be to have a bullet that is just barely stabilized in flight but cant stay stable upon impact--that is if you're not using a caliber big enough to do the job without having to do tricks. So i will stick with my .30+ guns for most things, but it's always good to have options.

[tomme boy]

Look at some of the old 303 Brit ammo. It was made to tumble on impact. I have a couple that have the front 1/4 of the bullet filled with rubber. Some others I have seen had paper in the nose.

One of the main problems with the 5.56mm is impact velocity. It has to be above a certain speed to make it tumble. When it tumbles it is supposed to fragment increasing the wound channel. It was the main problem when they switched to the M4 with the 14.5" barrel. The 20" barrel was not affected as much beacause of the extra vel. the longer barrel had.

[Ole]

The 7.62x39 Yugoslavian M67 ammo (FMJ) was also designed with a hollow space right behind the nose to increase the round's tendency to yaw after it hit flesh.

It's third from the bottom in this comparison picture:

http://i258.photobucket.com/albums/hh280/Ole1830/RussianWP.jpg

[Love Life]

probably make a tumbling boolit. Just create a boolit with an uneven hollowpoint thickness. The difference in weight will, in theory, cause the boolit to wobble on the way to the target. Once the boolit hit a fluid medium the uneven fluid pressure on the uneven hollowpoint cavity will, once again in theory, cause the boolit to yaw and tumble.

I'm not sure what the accuracy of this boolit design would be or if it could withstand the centrifigul force as it rotated out of balance through the air.

[felix]

The 32-30 with 16 twist using 170 grainers will act like these shown for the Russian on thin skinned game. The 30-30 with 12 twist acts more like what you'd expect. Hunters have known this since about forever. ... felix

[Larry Gibson]

Early XM16s had 14" twist, most commanly called "green guns" because of the color of the stocks. However, the 1st XM16s the 173rd got also had the 14" twist. There was a noticeable termanal performance difference between those and the M16s we got with 12" twists. I also had access to quite a bit of M193 and rechambered a Savage 24 .222 Rem barrel with 14" twist. Shot numerous coyotes and lots of rock chucks and jackrabbits with it and my M700V in 223 with 12" twist using M193 ammo. Solid hits from the 14" twist were most often quite effective. Same hits from the 12" hit would cause them to hump up and crawl or run off. Tests in newsprint wetpack confirmed the M193 bullets were tumbling when shot from the 14" twist soon after impact. The M193 from the 12" twist penetrated 12 - 14" in the wetpack before it began tumbling, if it did at all.

7.62 NATO (US M80) on the other hand was very destructive out of 12" twist barrels shortly after impact in most anything. 7.62 NATO, better than Master card or Visa, accepted worldwide....never leave home with out it........

Larry Gibson

[Lonegun1894]

7.62 NATO, better than Master card or Visa, accepted worldwide....never leave home with out it........[/I]

Larry Gibson



:drinks:

[Grapeshot]

From an old ordnance guy. A spire or pointed point and a FLAT BASED bullet will tumble after it hits soft tissue. The Gremans were very displeased with the US in WWI because of this. A boat tailed spire point will generally go needle straight thru soft tissue.

The flat based spire point will tumble because the aft end of the bullet has more mass than the front pointed end. As the front tries to slow down the rear continues its rotation and forces the entire bullet to swap ends a few times as it plows thru a body. Makes a mess of tissue as it does this.

British, French and German bullets, from reports I have read from back then were boat-tailed to make them accurate at longer ranges as they dropped out of super sonic and thru trans sonic enviroment.

[MBTcustom]

I'm glad I asked this. Not at all the answers I expected but very informative and educational!

[Reload3006]

actually the largest destructive force of any projectile is Mass X velocity impacting a hollow volume filled with liquid. That is why if you shoot a milk jug full of water even with a FMJ in a supersonic round it explodes. This is also why a lot of times if you shoot a pumpkin with the same round its a through and through. Shoot a Water Mellon it explodes. It is the hydraulic effect on liquid and semi liquid. If an animal is hit in the Thoracic cavity with a super sonic projectile all its going to leave in its wake is Mush. Expansion makes this even more devastating

[1Shirt]

Kind of looks like Larry Gibson and I were on the same quest for knowledge regarding the capacity of the early 223 stuff. My rechambered 222 Rem was a 1-14. Not as extensibe testing on flesh as his however, but did take a few p-dogs with it ball ammo. Not enought experiance for comparison however at the time. There was a lot of hoopalaw about tumbling bullets back then and Geneva convention standards etc. Arguements about projectiles and the Geneva convention go way back, and will probably continue as long as there is ground warfare.

I had Green Stock's for issue to AF Combat Controlers before the rifle was adopted by the other branches. Used to call them "Mattie Matels". It was AF Gen. Lamay who introduced them to the AF, and then they were picked up later by the other branches. I started in the Corps, and I cut my teeth on Paris Island on a Garand and still agree with General Pattons assessment of the Garand. Regardless of a bullet tumbling or not tumbling, the object of pulling the trigger is to put a hole of some kind in something. That may be paper, and animal or a human.
1Shirt!:coffeecom

[beagle]

Supposedly, the old 200 grain .38 Special "Police Load" was a tumbler. Pretty hard to drive one fast enough in a .38 Special to maintail stability and anything they encountered hard tended to deflect them and start tumbling. That's one reason the police departments liked them as they were manstoppers. I've loaded and shot a bunch of Lyman 358430 200 grainers and have noticed that upon impact in dirt, many will tumble but it's a hit and miss thing as many will penetrate. The 358430 is pretty near a wadcutter with one end rounded and with that long, blunt design, coupled with the fact that you're moving max lead weight at marginal velocities to stabilize, I could see the argument for good stability.

Still, that's a potent short range load and fun to mess with./beagle

[Cadillo]

1Shirt,
I have seen the modern M-16A2s firing 62gr FMJs, and those tend to drill straight through and have little to no effect unless they break bones or CNS. Now if you fire the same rifle with the issue 1:7 twist with a 75/77/80gr HPBT bullet, it is much more likely to be effective and seems to impress the target more.

Werent the original ealry M-16s 1:12" or 1:14" twist? If so, it would seem like the current 1:7" twist is TOO STABLE and less likely to tumble. I have talked to some Vietnam vets who were in during the transition from the slow to the fast twist and most complained about the faster twist being too fast and making an inefficient caliber even worse. Makes me think the perfect small-caliber combination would be to have a bullet that is just barely stabilized in flight but cant stay stable upon impact--that is if you're not using a caliber big enough to do the job without having to do tricks. So i will stick with my .30+ guns for most things, but it's always good to have options.

Original AR-15 and M-16 had 1/14 twist barrels, which did not stabilize the bullets in flight. They flew with a slight yaw, which caused tumbling upon contact with target. M-16 A1 was fitted with a 1/12 twist barrel in order to stabilize bullet and increase effective accurate range. Since then barrels have increasingly faster twist rates intended to stabilize longer and longer bullets in order to increase effective accurate range. Downside is poorer knockdown power especially with the shorter barreled M-4's.

[beagle]

Again, on .30 military ammo (and .50/12.75mm), Armor Piercing (AP) cores are vey bad to tumble. Most of these upon encountering almost anything will shed the jacket and the hardened core is on it's own stability wise. I've seen and recovered a lot of AP cores from aircrtaft hits in VN and almost always, they tumbled after shedding the core. Many penetrated parts of the aircraft and some left a very defined sideways print of the bullet profile. I recall recovering one 12.75mmAP core from a magazine of 40MM HE rounds and the core was shattered and many rounds had been broken apart and fuses seperated from projectiles. That was a hairy project. Another instance we took a AK AP through a 20mm case and it fed on into the M61 cannon and jammed. The case had a perfect silouhette of the AP core through the shoulder and the core was in the 20mm case. The propellant had ignited and the flame came through the hole in the case./beagle

[1Shirt]

Agree with Begal on AP. Would like a buck for every solid core only I have seen on the ground in berms when AP was shot. Have shot a lot of it in times past.
1Shirt!:coffeecom

[Larry Gibson]

"really after the Korean War, more thought was given to how to wound, not kill. The reasoning being, if you kill the enemy there is 1 less in the battle. If you wound an enemy, there are 3 less in the battle. The 1 wounded, 2 to care for him."

That is a myth, one of those quippy little sayings that sound cute. I spent 42 years in the Army (22+ active the rest NG and USAR). 30+ of it was in the infantry, armored cav and SF. Never ever did I here or read in any manual that that you shoot to wound the enemy. Numerous soldiers would use that quip but on questioning it was found they were never in a battle. The reason is this; we are the only ones with leaders who will stop an attack to care for one wounded soldier. Our enemies do not. They only care for their wounded if they've one the battle after the battle is over. Guess what that means you are? After the battle/attack is over, if you've won, then you have time and personnel to assist the wounded. The enemies we face and have faced understand that, we do not until it is learned by hard lessons.

If you are attacked, in an attack or battle of any size you must 1st and formost win the fight. You can not use combatants and lesson your fire power and ability to fight by assisting casualties. That's why Soldiers/Marines are taught self aide and minimal wound dressing. There are medics to care for the wounded. After the fight, again if you've won, you can carry the wounded somewhere. All sizeable units have medics and should have casevac plans that do not negate any part of the combat force.

An infantryman's job is to close with and kill the enemy. What part of that do we find "wound the enemy" in..........

Larry Gibson

[MtGun44]

A pointed bullet is stable base first in dense media like muscle or gelatin, so it will turn
around.

Many like the early 55 FMJ BT M16 ammo had a cannelure and would break in half at the
cannelure during the swapping ends part. This meant that shallow wounds were like a
pencil stab because the bullet staye straight. But when it had enough time to swap ends,
it would break up and fragment, causing a huge wound. This is why you get reports of
massive wounds sometimes or "heck that silly little Mattel toy doesn't do anything but punch
a tiny hole" from veterans.

All of them will turn around, and make a big cavity when sideways. The questions are:
Is the media deep enough to get the swap ends effect? Is the bullet going to stay together
or fragment from the sideways forces?

Some German 7.62 NATO would do the same thing as early 5.56 NATO when tested in
gelatin - fragment when it yawed sideways. Slow twist rifling in early M16s increased the likelihood
of swapping ends and blowing up, making it happen sooner after impact.

Lots of info by Fackler and others on the behavior of bullets in test media and in actual animal flesh.

Bill

[303Guy]

It's possible and apparently common to have a 5.56 NATO bullet do a small hole in and small hole out on a human target but with the bullet having done a 180° inside the target. That's not my observation - just reading studies on bullet performance.

[Jammer Six]

There used to be a sign at Camp Liberty Bell that warned A Co, 2/9th against wounding the enemy.

The rest is arm waving.

[Larry Gibson]

HammerMTB

No problem with the response what so ever, you're entitled to your opinion also.

My opinion is based on 42 years in the Army with basic and advanced infantry training as an Airborne infantryman (scout), as a scout in armored cav (trained in that/trained others), as an SF weapons, intelligence and operatios NCO (lots of SF training), as a full time training NCO (trained lots of others in marksmanship, both our soldiers and those of other nations) for 42 years (22 1/2 years active duty and 20 years active NG and USAR). In there I also attended the SE Asian Wargames twice (we came in second BTW), spent a lot of time in numerous s**t holes through out the world and spent all of 2005 in Iraq (looks like we'll come in 2nd there also). And, as a civilian contractor training Marines, Soldiers and CBs for another 3 years.

Now in all that time, of which a considerable amount was training infantrymen of ours and numerous countires, other than a few well meaning but uninformed and inexperiences idividuals would say that cute, quippy saying. Nowhere did I hear as policy or as a tactic or read in any manual (I actualy read and studies most of them dealing with marksmanship, weapons and tactics) that cute, quippy little saying. To the contrary, you will find the mission of the infantryman is to; close with and kill the enemy. BTW; do you remember the Spirit of the bayonet? If not then let me refresh your memory....it is "to kill! It is not "to wound so 2 other enemy soldiers will be taken out of the fight to carry the poor wounded enemy back somewhere......"

It is the same when and infantryman shoots and enemy, machine guns them with 7.62 NATO or a Ma Deuce with .50 cal, grenades them, calls in artillery or airstrikes on them or, back in the day, napalm......none of those are now, or ever were, intended "to wound the enemy". So what would make us think we would adopt a rifle/cartridge for just the lowly infantryman to want to just wound an enemy with just a rifle? In retrospect that quippy little saying doesn't make much sense in context with the whole amount of death and destruction we deal out, now does it?

Larry Gibson

[Hickory]

Original AR-15 and M-16 had 1/14 twist barrels, which did not stabilize the bullets in flight. They flew with a slight yaw, which caused tumbling upon contact with target. M-16 A1 was fitted with a 1/12 twist barrel in order to stabilize bullet and increase effective accurate range. Since then barrels have increasingly faster twist rates intended to stabilize longer and longer bullets in order to increase effective accurate range. Downside is poorer knockdown power especially with the shorter barreled M-4's.

I have killed a lot of prairie dogs over the years and have noticed early on that my first 223's with the 1-14 twist, the bullets would not react the same way every time when hitting a prairie dog.

When I had them rebarreled with a 1-10 twist barrels the bullets would react in a more prescribed manner. You might not believe this, but shooting doubles and triples was easier, almost like shooting pool.
I could put a little "English" on the first prairie dog and the bullet would take a more consistent path through the prairie dog. Giving me a better chance to get the ones a little off to the side.

I attributed this to a more stable bullet.
I also noticed that with the 1-10 twist, I could get an extra 50-60 yds of accurate shooting.

I think the slower twist will cause a bullet to tumble more so then the faster twist barrels.

[BAGTIC]

Yep. I have recently started experimenting with really soft boolits and a PB gas check in the 357 mag. Good things are happening so far.

One of the main reasons for the tumbling of the spire point is once it enters a fluid medium the lighter nos slows down faster than the heavier base. In theory, and practice, this is what causes the tumblin and sometimes shredding of these boolits. Now these are FMJ bullets and not hollowpoint or open tip.

Now a boolit that comes tumbling out of the barrel will tumble in the fluid as well. Or the FNJ will just drill a straight hole. It's a wild card.

Sorry but not so. The whole bullet slows together. The only difference is the infinitesimal difference if the nose crushes but as soon as it does the whole bullet again travels at the same speed.

The bullet tumbles because the base is heavier that the nose (shuttlecock effect) like an arrow launched backwards will quickly swap ends.

Never saw a bullet come tumbling out of the barrel. Tumbling only starts after it has cleared the bore and is acted on by the airstream. It only swaps ends, once, whether that constitutes tumbling is a matter of definition.

A bullet can go in, swap ends, and come out base first leaving a small entrance and exit wound with little to no external evidence of whether it exited point first or base first. An ogival spitzer type bullet will almost always swap ends in a foot or so distance travel.

[BAGTIC]

I don't often find myself on the side of Gibson but this time both he and MtGun are right. Armies all over the world have done extensive research on wound ballistis and terminal effects and they all find the same thing.

Modern bullets are specifically designed to break up in tissue. The German .308 does so considerable better than ours. Think why so many military bullets use two part cores. The junction of the two separate cores creates a weak spot that causes the bullet to fragment when it tumbles. Some bullets tumble sooner than others with the result that if they hit a relatively thin part of the anatomy they may go straight though while if they hit someplace like the trunk they will fragment, possibly without an exit wound.

[MBTcustom]

Why oh why do people have to hang out there dirty laundry on an otherwise informative thread?
I respect Larry Gibson, and I happen to think that his argument makes a lot of sense in this particular issue.
I also respect HammerMTB's original comment (second hand, a generation removed though it may be.)
I do not appreciate antagonizing/retaliating language that makes only vague reference to the issue at hand!
This gets perfectly good threads locked by the moderators (had it happen) and only generates hard feelings.
If you cant help retaliating, please do so in a PM so the rest of us can read and study in piece, or better yet, go find a liberal to beat over the head! We are all shooters here, why is it necessary to conduct ourselves like this?

[MBTcustom]

Now, back on the original issue. My dads comment was that lead boolits will always tumble when contacting soft flesh. While I have collected 45 pistol boolits that obviously started rolling when they contacted soft mud, all the rifle boolits have had a consistent mushroom tip.
I gather from the information gathered so far, (mostly pertaining to jacketed bullets for some reason) that the twist has a lot to do with it.
Does anyone have info pertaining to the shape/SD/length/speed of boolits and their effect on tumble?

[Larry Gibson]

goodsteel

It is generally believed that bullets with higher sectional densities are better penetrators and don't tumble as easily. With FMJs or non expanding lead bullets there is a lot of merit in this. However the shape of the bullet and location of the center of gravity of the bullet influence it. Another consideration is that on broadside shots of deer/game or frontal defensive shots on humans there just may not be enough time in target for any noticeable "tumbling" to occur. With HPs and SPs it is different as the expansion through various densities of flesh and bone can decidedly alter a bullets course and cause "tumbling". As with many things in shooting, especially terminal ballistics, probably not a set answer.

Larry Gibson

[waksupi]

I have never had any indication of cast boolits tumbling on game shots. And I have shot quite a bit of game with them over the years.

[MBTcustom]

Well, so far, I have only personally shot one deer with a cast boolit. I was using my muscle loader, but I had it loaded with the "king" of supposedly tumbling boolits: the 230gr RN .452. The very rounds that I run in my 1911. I shot the deer and it was DRT. No evidence of a tumbling boolit.
That was a short fat boolit, I got to see another one this year that was killed with a long skinny boolit: 250gr .358 cal RN, again, no signs of tumbling.
I understand how a pointy, copper jacket boolit would tumble, (like the ilustration on the first page) but it seems to me that the closer you get to a short, slow, fat, soft lead boolit, the less likely you are to see this erratic behavior.

[Love Life]

Sorry but not so. The whole bullet slows together. The only difference is the infinitesimal difference if the nose crushes but as soon as it does the whole bullet again travels at the same speed.

The bullet tumbles because the base is heavier that the nose (shuttlecock effect) like an arrow launched backwards will quickly swap ends.

Never saw a bullet come tumbling out of the barrel. Tumbling only starts after it has cleared the bore and is acted on by the airstream. It only swaps ends, once, whether that constitutes tumbling is a matter of definition.

A bullet can go in, swap ends, and come out base first leaving a small entrance and exit wound with little to no external evidence of whether it exited point first or base first. An ogival spitzer type bullet will almost always swap ends in a foot or so distance travel.

Your wrong bagtic. Pure and simple physics. The lighter nose slows down while the heavier back end maintins a stronger forward momentum. As the lighter nose slows down and the heavier base treis to continue, the base swings around giving you that wonderful tumble and yaw.

That is fact based off of years of established observation.

As for the bullets being designed to break up, and thus having a two part core is not entirely true. The steel penetrator was designed for the use against body armor, light skinned barriers, etc.

I'm done on this thread gents. It has turned into speculation, and complete ignoring of facts, with a little BS thrown in. If you heard it from somebody, who heard it from somebody, who read an ordinance book, who had a friend who knew somebody in the military then it might not be the gospel.

[Larry Gibson]

HammerMTB

You asked the question; "Can it be false because you "never ever heard or read of it?" " I answered that question. You should be careful of what you ask for as you may not like the answer. You've told me to "take a chill pill", suggest it is you who need to take the pill.

BTW; the 7.62x51 was not "dropped". Fact is the 5.56 proved inadequate to the point that the M60 machinegun (7.62x51) was moved from the general purpose category to one of being the squad automatic weapon during the Viet Nam war. It was replaced by the SWA in 5.56 which has been found to be inadequate in the current war and was replaced at by the M240 and now a new LWMG in guess what? Hmmmmm...guess we want only the poor lowly rifleman to "wound" the enemy, the MG gunner can kill them eh?

Also have you bothered to read read all the adverse reports on the 5.56s lack of "power" and ability to "stop" the enemy in SWA? The 5.56 is wounding the hell out of the enemy though.......seems like nobody is validating that quippy little saying............It's the quippy little saying that "All can agree that's silly on the face of it". You need to give it a rest.

Larry Gibson

[Reload3006]

actually all FMJ rounds were more to observe our participation in the Geneva Convention treaties than anything else. Military philosophy has always been to stop the enemy combatant. History teaches that during the Philippine war the 38 S&W was found lacking in its stopping power when confronting the Moro warriors. So S&W developed the 38 Special. But for the military that wasn't quite sufficient and they opted for the 45acp. It has often been discussed in battle tactics at least in the Navy, and Marine Corps that to wound an enemy combatant is more beneficial than to out right kill him but the bottom line is to stop the enemy by what ever means necessary with in the moral confines of Geneva.

[Larry Gibson]

Most all bullets selected for "penetration" are long for caliber, heavy for caliber and have blunt noses. I seriously doubt you'll find any DG hunter in favor of a short, slow, fat bullet for maximum, straight penetration. I'd bet most all of Waksupi's CF cast bullets meet that criteria. Even the "hard cast" boys shooting revolvers want heavy, long for caliber bullets. However, throw in the "soft lead" and the equation changes because of expansion. On deer, pigs and elk I can't really recall any non FMJ bullet, of proper construction (cast or jacketed) to hold together, not giving sufficient penetration and with the wound channel following a reletively straight course through the animal. Perhaps as Waksupi indicates; this whole discusion is perhaps a moot point or a "myth" as asked in the thread title?

Larry Gibson

[Love Life]

The opinion the U.S. infantryman (me being one of them) are trained to wound is absurd. Why would I want to wound the enemy so he can live to fight another day? I want to kill him. His buddies will leave him in the street if wounded. That wasn't read in a book that was seen in real life on numerous occasions.

I have seen the 5.56 in action in combat. It is a wild card. Sometimes it kills them deader than a doornail, and sometimes they run up the street and round the corner after taking a burst to the guts from a saw.

Shooting people is like shooting game. Aim for the vitals IE solar plexus, lungs, heart, double lung and heart etc. If you gutshot a deer it runs. If you gutshot a person it runs. Now if you send a few through the pelvis then they aren't running anywhere, but will just lay there in pain until the battle is over and our Corpsman risk there lives to provide the enemy first aid.

The trained to wound is a saying started and continued by REMF and armchair warriors. The book "On Killing" actually shows how military personnel were trained through the use of realistic training and human shaped targets to actually shoot at the enemy instead of just sitting there. It documents how firing rates went up war by war with the advent of new training. It also covers desensitizing yourself and troops to killing by make the enemy less than human. This is accomplished by calling them by their slang names. You would say "I just smoked some haji" instead of saying "I just killed somebody's dad, son, etc."

The book is interesting in it also talks about the desensitizing of our youth to violence through violent games and TV programs. It is a good read if you actually read the book and not the cliffnotes.

[Reload3006]

I Couldn't agree with you more Love Life as I much preferred my m14 over that *** 16
I should have went on to say that I preferred the 14 because it would throw a gook down shoot him again watch him bounce you know he isnt going to kill you or a buddy. While the 16 or 5.56 would get the job done most of us didnt like it because its effects wasn't as immediate. Definitely a 5.56 will punch your ticket. But it doesn't have the kinetic knock down of the heavier round.

intent to wound being more beneficial I agree its a subject for REMIFs but where the rubber meets the road your shooting to kill not wound. or more precisely your shooting to STOP by what ever means necessary.

[Love Life]

I Couldn't agree with you more Love Life as I much preferred my m14 over that *** 16
I should have went on to say that I preferred the 14 because it would throw a gook down shoot him again watch him bounce you know he isnt going to kill you or a buddy. While the 16 or 5.56 would get the job done most of us didnt like it because its effects wasn't as immediate. Definitely a 5.56 will punch your ticket. But it doesn't have the kinetic knock down of the heavier round.

intent to wound being more beneficial I agree its a subject for REMIFs but where the rubber meets the road your shooting to kill not wound. or more precisely your shooting to STOP by what ever means necessary.

Amen.

Goodsteel-Sorry your thread got hijacked so bad. To get it back on subject I give the same answer I gave in my first post.

It is not a myth. It does happen and when it does it is extremely detrimental to whatever it happens to. The problem is getting it to do it consistantly, because just like hollowpoints not expanding at times, a bullet/boolit designed to tumble and yaw may not do it all the time.

A good stable hollowpoint will get done what needs to be done.

[MBTcustom]

Well I ascertained that tumbling with
Cast Lead Boolits
is the exception and not the rule, and that was the original intent of the thread.
Lord knows I respect the heck out of you fellas for doing what I wouldn't and serving in the military. I'd give you the shirt off my back in a heart beat, but seriously, if I wanted to know about copper jacketed bullets (that play by very different rules) and the roles they played in every war that occurred in the last century, do you realy think I would ask that question on the castboolits forum, on the castboolits web-sight? do you think that anybody who was looking for that information would look here? Not likely.
It would make for a good read if not for the defensive and antagonizing language.
I dont understand why this happens. I asked a very fair question, and I even asked in a jocular manner. What was it about the way I worded it that made folks think that they could speak so disrespectfully to each other?
You would have thought that in all the training and passed down information, that somebody would have taught these folks that you dont start a fight in your own back yard, or keep it going.

[MtGun44]

Sorry that I contributed to the off topic excursion.

As to lead boolits - no is the short answer. The closest effect that I can think of that
may be interpreted that way would be hitting a bone and upsetting the boolit and
then having it tumble, perhaps with bone fragments, greatly increasing the wounding
effect.

Pointed bullets will swap ends, but round nosed and flat nosed ones will drive
straight, barring impact with something hard like a bone. Very few lead boolits have
historically been spitzers, although they are not altogether unknown. Lead spitzers
may come close to the effect, swapping ends and perhaps not being up to the loads
when sideways. I cannot think of any factory rounds ever with spitzer lead boolits, and
I would think that most folks when discussing shooting are usually talking about
factory ammo.

Bill

[kir_kenix]

Regarding CAST BOOLITS...I'm not aware of any in depth studies on tumbling with Pb projectiles.

My first instinct would be to ASSUME that a long for caliber boolit with a spire or hollow point that is marginally stabalized has the best chance of tumbling on a consistant basis. I've had plenty of long(ish) for caliber .30 boolits appear to tumble (or at least switch ends) while travelling thru deer sized game. Nothing defenitive as I'm not a CSI or gunshot wound expert.

My best guess is that semi or full wadcutters at handgun speeds are unlikely to CONSISTANTLY tumble without hitting something solid. Experimentation is called for! The only way to know for sure would be to set up some balistic geletin and/or a high speed camera.

If I was trying to get a cast boolit to tumble out of a handgun I would:
1. Find the longest .359 boolit available
2. Hollowpoint it
3. Fire it out of a short barreled .357 Mag (sub 2")
Maybe I'll give this a try sometime this spring if I ever get any free time. Outcome sounds interesting, even if its ultimately not applicable in self defense (I've always been an advocate of assuring there is plenty of ventilation introduced on the target and not worrying too much about bullet performance).

Good luck and let us know if you or anybody else runs any experiments.

[MBTcustom]

Is there a dirt cheap way to make ballistic gel?
I will try this if I can get some gel together. I have some realy long 250gr .358 boolits that I can hollow point on the lathe or something. While waiting for an answer Ill look for a sticky.

[quilbilly]

I did the "wet phone book" test on my 30/30 about a year ago. The boolits began tumbling at about 6" of penetration and for the next 11" made an absolutely vicious wound channel. The test was done at 40 yards with a Lee 160 gr RN boolit at an MV of 1550 fps.

[MBTcustom]

Interesting!

[Jammer Six]

He did 3 tours in Korea, some shipboard, some on the ground with grunts.
During the Korean war, (1950-1953) there was no such thing as a tour.

The remnants of the first people to land were there at the end.

[MBTcustom]

Not only that but there were no cast boolits used in the Korean war. [smilie=b:
What good does this post do but try to stir up more unrelated trouble?
Please, if you dont have anything to say about the pursuit and study of the cast boolit and its performance, just dont post it here. I'm absolutely sick of the arguing about wars that had nothing at all to do with the original intent of this thread or this area of the web-site.
Thank you all for keeping it civil.

[Love Life]

Goodsteel- The idea from Kir Kenix about the long SP that is marginally stabilized could be promising.

With the WFN, LFN, and LSWC the weight is too evenly distributed and the thickness is dang near uniform for the majority of the boolit length. That is why tumbling doesn't happen unless abone is hit, and even then will more than likely punch through.

A SP with a long nose and a big fat butt will have much better chances of tumbling and yawing. I bet if you were to make a SP with a kind of groove on the forward skinnier portion you could very much increase the possibility of getting the boolit to tumble, yaw, and break apart. That is only a theory. Once I get my new 8mm mould I will give it a try. What do you think?

[quilbilly]

I should have added to my previous finding about my 30/30 boolits tumbling that I did a similar "wet phone book" test with my 7mm TCU using the Lee 130 gr RN boolit at 1900 fps muzzle velocity and it did not tumble but expanded beautifully. I just picked up another stack of phone books today for future terminal ballistics tests.

[MBTcustom]

A SP with a long nose and a big fat butt will have much better chances of tumbling and yawing. I bet if you were to make a SP with a kind of groove on the forward skinnier portion you could very much increase the possibility of getting the boolit to tumble, yaw, and break apart. That is only a theory. Once I get my new 8mm mould I will give it a try. What do you think?
Well, I dont know about a groove, and it seems to me that the trick here is to get the boolit to stabilize just enough to get to the target because asking it to suddenly do a backflip after it hits flesh, is asking a lot IMHO (seems like it would be hard to get a realy accurate boolit to perform this way.)
But I think I have just the one for the job.
Check out these babies:
http://i1120.photobucket.com/albums/l481/goodsteel/IMG_0850.jpg
http://i1120.photobucket.com/albums/l481/goodsteel/IMG_0853.jpg
http://i1120.photobucket.com/albums/l481/goodsteel/IMG_0871.jpg
So hollow point it, go with a hard alloy (I would think that if the boolit mushrooms then it will suddenly be a short fat blob again that will not tumble.)

[Love Life]

Let me know how that goes Goodsteel. I was also thinking a reverse softnose. Lino nose and pure base. Very labor intensive so probably not worth it.

What boolits is that?

[Reload3006]

Pb boolits like Jacketed variety need to be stabilized or they will tumble. before they impact. While they aren't of the jacketed variety they do operate the same way they are in fact a projectile subject to the same ballistic effects as any other bullet. Velocity and alloy will dictate more on how the terminal performance acts than anything else as was mentioned before so will design. So if you have a marginally stabilized projectile chances are it will tumble before or on impact. if it is well stabilized it will probably not tumble before or after impact. So your alloy becomes critical the harder the alloy the less likely of more damage to tissue than the diameter of the hole punched through. Soft alloy it will pancake and punch a larger hole. and velocity plays a big role too for the hydraulic Shock created in Liquid and semi Liquid tissue.

[Love Life]

I agree reload 3006. Of course if you punch holes in the vitals all is not lost.

Goodsteel- What brought this up? Are you trying to get your boolits to tumble on game or is this just an experiment? I would think a well made hollowpoint would be just as effective as a tumbling boolit. If not more so. I'm just wondering what your intended use is.

I am interested though. Guess I better get to the drawing board.

[oneokie]

So hollow point it, go with a hard alloy (I would think that if the boolit mushrooms then it will suddenly be a short fat blob again that will not tumble.)

You can vary the depth of your hollow point to tailor the amount of instability you want to achieve.

[Larry Gibson]

Goodsteel

I would not go with the hard bullet HP blow off the nose and have the base penatrate idea. I already went through all of that many years ago. I have been hunting and shooting deer with .30, .31 and 8mm cast bullets for 40+ years. I have been experimenting with alloys and HPs for just about as long. I got my 311041HP mould in '69. I also got my 323471HP mould in '72. I have been using a Forster HP tool, 1/16th and 1/8th, on other cast bullets since the mid '70s.

You will find a cast HP of a malleable alloy that expands well (usually with a shallow HP of 1/8" to not more than 1/3 the length of the bullet nose) without sloughing off the expansion petals will give the best terminal results.

BTW; of all the deer I have shot with cast .30, .31 and the 8mm bullets I can not recall a single instance where the bullet tumbled. I also have not recovered hardly any of those bullets as all were through and through with excellent wound channels from entry through tissue and bone and to the exit.

Larry Gibson

[MBTcustom]

OK, what brought all this up is that the "fact" of tumbling boolits, is a principle that has been taught to me by my father since I was little. Also I car pool with him every day and I'm afraid I bend his ear nigh the breaking point about all the awesome stuff I have learned here. Most things we agree on but I am fostering hidden doubts as to the validity of this particular pearl of wisdom.
Add to that, the occasional time when hollywood brings up something related to this issue (which automatically makes me think they are wrong). For instance, the scene in "Silver Bullet" where Gary Busey goes to the gunsmith to get a silver boolit made so he can shoot the wherewolf. The comment was made by the smith: "Its got a low grain load....so it wont tumble. Aught to be pretty accurate...."
Its one of those things that I believe happens sometimes but is given much more credence than it deserves (at least in my circles).
Its one of those things that I thought "heck why am I still wondering about this? I'll ask the fellers on castboolits and sure as the sun rising, some guy will tell me more than I ever wanted to know about the subject, and all my questions will be put to rest."
Again the statement that has been taught to me as gospel truth: Heavy, boolits especially wad-cutters, and those that have a wide meplat, always tumble like a boomerang when they hit flesh and thats what makes them so much more effective than a regular mushrooming hollow-point.

We shall see.

[Love Life]

I'm interested. Please keep us posted with your results. If a boolit can be made to tumble reliably then that would be cool.

I hope you didn't take me asking "Why" the wrong way. I was just curious and meant no harm.

[MBTcustom]

No offense whatsoever! Its a fair question.
Now I still need ideas as to a realy cheap way to make ballistic gel.
I saw the stuff that Corbin sells, and although it is just as cool as a dead polar bear, it has one major drawback in that it is opaque in appearance. You can certainly see what happened to the boolit, but the damage path that would show the tumbling (or not) would be obscure. I would think that it would just leave you guessing as to what went on inside the test blocks.

[BAGTIC]

The hangun cartridge originally used in the Philippines was not the .38 S&W it was the .38 Long Colt.

[Love Life]

Have you done any testing yet?

[MBTcustom]

Not yet, I'm sick as a dog, broke as a duck, and busier than a centipede at a toe countin' contest.
I may get it done after Christmas, but I still need to order knox gelatin.
Does anybody know where is the cheapest place to get that stuff? Im going to need a lot of it.

[390ish]

Think with most pb long bullets (pistol bullets are not long) you are going to see more banannas if there is tumbling or an attempt at tubmling. They are not generally moving at a rate fast enough to create fragmentation as m193 or the German DAG 308. I think just about anything a certain length to caliber fired out of a rifle at around 2500 fps will tumble if it does not otherwise expand itself into stopping before rotation would otherwise occur. 6.5 jap issue ammo was a show stopper in that regard. slow down from a perfect mushroom. The one thing that makes me wonder about it with pb boolits is the grease groove combination, i think it may lower the shank weight relative to the nose weight to where there is a lot more stability than you might expect, even with longer projectiles. From what I understand the Mk VII 303 Brit was great because it was a flat base, long bullet that just had to rotate early and often.

[x101airborne]

Again, on .30 military ammo (and .50/12.75mm), Armor Piercing (AP) cores are vey bad to tumble. Most of these upon encountering almost anything will shed the jacket and the hardened core is on it's own stability wise. I've seen and recovered a lot of AP cores from aircrtaft hits in VN and almost always, they tumbled after shedding the core. Many penetrated parts of the aircraft and some left a very defined sideways print of the bullet profile. I recall recovering one 12.75mmAP core from a magazine of 40MM HE rounds and the core was shattered and many rounds had been broken apart and fuses seperated from projectiles. That was a hairy project. Another instance we took a AK AP through a 20mm case and it fed on into the M61 cannon and jammed. The case had a perfect silouhette of the AP core through the shoulder and the core was in the 20mm case. The propellant had ignited and the flame came through the hole in the case./beagle

I bet that rated about a 9.9 on your "O'Sh$@-O'meter"!!

[BAGTIC]

[QUOTE=Love Life;1506231]Your wrong bagtic. Pure and simple physics. The lighter nose slows down while the heavier back end maintins a stronger forward momentum. As the lighter nose slows down and the heavier base treis to continue, the base swings around giving you that wonderful tumble and yaw.


When you are riding a horse and come to a fence and the horse balks throwing you head first over the fence which end of the horse stops first?

[XWrench3]

No myth. I have a 223 with a 1 in 12 twist rate. I shot some 75 grain hornady a-maxes thru it. Tumble city. The reason was not a fast enough spin rate to stabilize such a long heavy bullet. But when it hit, it made a big mess of whatever it did hit. I shot a broken off pine branch with it at about 40 yards. It blew a cup shape chunk out of it, taking about 3/4 of the entire limb circumference with it. I would really be afraid of what it would do to a human or animal body.

[303Guy]

How a mushroomed boolit works is it creates a vapour pocket behind the mushroom around the boolit, keeping material (flesh) from touching it so it tends to stay nose forward.

[SlippShodd]

Adjusted for inflation, here's my 6 cents worth...
I can relate 2 instances of tumbling CAST bullets in my experience. First was loading hollow-base wadcutters backwards in .38 Special with 3.5 grains of Unique, fired from my wife's Ladysmith (2-inch 36) at 7 yards, into phone books. Accuracy was horrible, but several of the rounds *entered* the cover of the books in full profile, suggesting they tumbled well before impact. Shot several at less substantial paper targets taped to cardboard displaying the classic keyhole as well. I recently loaded some more of these to try through my 6" gun to see if they stabilized any better. Just need to remember to pack them to the range.
Then there was loading 255 grain .452 pistol bullets in 45-70 cases with 11 grains of Unique, shooting in an original 1873 Trapdoor Springfield (long barrel, waaaay undersized bullet, low-pressure, low-velocity). These made an audible buzzsaw noise as they exited the barrel and left many full profile entry wounds in old, rotten logs at 25 yards. I laughed like a little kid, that was so much fun. :lol:

mike

[MBTcustom]

SlipShod, you are talking about tumbling on the way to the target, I am talking about tumbling after the boolit impacts the target. I have a boolit that seems to like to tumble in this way. Its the Lyman 358318. Two deer were shot with this boolit out of rifles that I built with 1-14 twist rate. Both deer displayed classic oval exit wounds and massive wound channels. Those deer died more suddenly from that boolit @ 2000 FPS than the ones I shot with the 300winmag @ 3200FPS. So that is one boolit that I feel fairly confident that I can say that it always tumbles at this certain velocity.
I was taught by my dad, that cast lead boolits always tumble in this way after hitting flesh or significant fluid obstruction. It seems to me, that would be a hard theory to disprove unless you had some way to see the path of the boolit through a fluid medium.
Short pistol boolits may not exit an animal, and paper is too week an obstruction to get the boolit to start flipping. This could easily have been missed unless someone was doing balistic gel tests and looking for it.

[MtGun44]

Very dependent on boolit shape and twist rate to get to the situation where it will tumble
quickly. Spitzers are stable in fluids backwards, FN seem to be stable frontwards. The
tumble is usually just one turn of 180 deg, swapping ends for a spitzer. This is
well documented by Fackler in Wound Ballistics, info with wound paths, intended for doctors.
Some of the bullets are not up to the stresses and come apart.

This report is for jbullets, and they can vary the density, like the Russian 5.45 ammo with
a hollow inside the nose of a long spitzer to make it swap ends sooner, and cast
has constant density (although a HP can shift this) and less able to make odd
wt distributions. I still think that the spitzer shape, even if uniform, solid material, will
be unstable point forward in flesh, and stable base forward, so it will "want" to swap
ends. I would think that many cast boolits might break up when sideways in the
turning process.

Bill

[Cadillo]

There are various reasons why a bullet of constructed ANY MATERIAL may tumble upon contact with flesh, and regardless of material, design etc., a bullet that is not spun fast enough to be properly stabilzed in flight and thus going downrange with a yaw, will most often turn turn to some degree and either keyhole of even tumble.

If someone says that their cast or swaged lead bullets are tumbling on contact with flesh, one of the possible or even likely causes is that the bullet is on the long side for the twist rate used, and is experiencing some degree of yaw in flight.

[DrB]

A pointed bullet is stable base first in dense media like muscle or gelatin, so it will turn
around.

Many like the early 55 FMJ BT M16 ammo had a cannelure and would break in half at the
cannelure during the swapping ends part. This meant that shallow wounds were like a
pencil stab because the bullet staye straight. But when it had enough time to swap ends,
it would break up and fragment, causing a huge wound. This is why you get reports of
massive wounds sometimes or "heck that silly little Mattel toy doesn't do anything but punch
a tiny hole" from veterans.

All of them will turn around, and make a big cavity when sideways. The questions are:
Is the media deep enough to get the swap ends effect? Is the bullet going to stay together
or fragment from the sideways forces?

Some German 7.62 NATO would do the same thing as early 5.56 NATO when tested in
gelatin - fragment when it yawed sideways. Slow twist rifling in early M16s increased the likelihood
of swapping ends and blowing up, making it happen sooner after impact.

Lots of info by Fackler and others on the behavior of bullets in test media and in actual animal flesh.

Bill

This... +1

Also need to remember that depending on the velocity regime and geometry the behavior can be very different.

A relatively blunt nose/meplat can cause the flow to separate and form a cavity completely around the bullet, which can both reduce shear drag and facilitate straight line penetration.

Anything that increases the area of blood vessels/nervous tissue/lung sheared will increase lethality (a bullet penetrating sideways, expanding, etc).

I would recommend duncan mcphersons book "bullet penetration" for a treatise on lethality of low velocity bullets (those with velocities low enough that tissue damage is dominated by shear of bullet passage). I've got a nit to pick with his similarity parameter derivation, but otherwise I think the whole book was great.

He also passingly discusses stability in penetration of higher velocity rifle bullets, and difference in tissue damage mechanism.

[Grandpas50AE]

Goodsteel,
My brother and I used a recipe out of an old Lyman book (I think, could be Guns&Ammo magazine in the early 70's) that was 50% paraffin/50% cup grease melted together and poured into aluminum roasting pans. Worked really well, except .41 mag and .44 mag went though 14 of them (they were about 2" thick IIRC).

As to the M16, the idea of tumbling was to get a bullet that would "tumble" up or down a bone structure (like arm or leg) when encountering a bone at an angle, instead of punching straight through. This was a means of circumventing the Geneva Convention that prohibited the use of soft point, hollow point, or "dum-dum" rounds by designing a bullet that would follow bone structure and disrupt the major blood vessels that typically run along them.

[mpmarty]

Ayup. 7.62 Nato turns cover into concealment, in a hurry.

[MBTcustom]

As to the M16, the idea of tumbling was to get a bullet that would "tumble" up or down a bone structure (like arm or leg) when encountering a bone at an angle, instead of punching straight through. This was a means of circumventing the Geneva Convention that prohibited the use of soft point, hollow point, or "dum-dum" rounds by designing a bullet that would follow bone structure and disrupt the major blood vessels that typically run along them.
Wow! and all this time I thought that the whole concept of the 5.56 NATO was based off of the .222 remington cartridge which had been developed for shooting ground squirrel and other similar pop-can sized game.
All this time it was to satisfy the Geneva Convention? I mistakenly thought that the 30-06 had a slight advantage over the 5.56 even when encountering those pesky bones. I was foolishly under the impression that our government sent the troops into a battle they couldn't win with a gun that wouldn't work that shot groundhog ammo and cut cost.
Not that I spend my every waking hour mistrusting our government you understand, I think that most times the right thing ends up going through, but in the case of the 5.56/M16 I think its pretty clear what their motivation was.
I have heard the argument that you stated above, many many times, and it still doesn't cut the mustard with me. I think its a lot of big talk about a small cartridge that was fed us by the government to instill a little confidence, while at the same time minimizing the incredible foolishness of that decision.
You can argue me till your blue in the face, tumbling or not, there is nothing that the 5.56 can do that cant be trumped by either 7.62 NATO or 7.62X39.
Sorry for the rant, I have strong opinions on this subject.

[nanuk]

GS: for Knox Gelatin, try a bulk food store, or a health food store that deals in bulk

[MBTcustom]

Yeah I was going to do that, but Its still going to be pretty pricey. Another challenge I have is that I dont have a refrigerator big enough to set the stuff up. I'm going to see if it will set up on its own given enough time. I am also contemplating what is the best method to get a mold going. I would realy like to make ten blocks at once 6" X 6" X 36" at least.
Anyway thats the hold-up. Expense, and facilities.

[runfiverun]

boxes [like from the post office] and saran wrap will make nice molds.
want 6" wide? cut them in half i bet a wire pulled through the blocks will cut it nicely.
if you over stabilize a bullet it will spin with the nose up.
if it hit's something it's gonna flip. [downwards]
the bullet can corkscrew through the air around it's flight path also.
and flutter at lower speeds [destabilize when becoming subsonic]
stabilization is a factor of speed and bbl twist rate.
that's why the shorter m-4 16" bbl's fail. the bullets are very stable, not too fast or too slow or on the edge of either.

[Jammer Six]

]You can argue me till your blue in the face, tumbling or not, there is nothing that the 5.56 can do that cant be trumped by either 7.62 NATO or 7.62X39.
I'm sorry, but I disagree.

There is one thing that the 5.56 wins, hands down, and it is the thing that tipped the balance.

The 5.56 wins the rounds-per-pound-of-load contest.

[BAGTIC]

A bullet with a long spitzer ogive is more prone to tumbling than one with a shor togive. That has been known since at least 1910 when the British introduced the Mark VII .303 round. That is why big game bullets where deep straight penetration in desirable have traditionally used round noses.

The farther the center of gavity is behind the center of drag the more likely a bullet is to tumble.

Bullets with long ogives are longer for their weight than bullets with shorter ogives and are therefore normally less stable to begin with. The denser the material it is passing through the less stable the bullet becomes. Tissue and water being much denser than air greatly diminishes stability.

Stability has nothing to do with a vacuum being formed behind the bullet. As a bullet mushrooms it also becomes shorter and shorter bullets as usually more stable than longer bullets. I suspect that the increased diameter of an expanded bullet also increases the flywheel effect (gyroscopic stability) of the bullet but that is just a personal opinion.

It seems unlikely that a bullet would tumble repeatedly. One it has flipped end for end it is going to be pretty much in a drag stabilized attitude like a dart with most of the weight forawrd and most of the drag aft.

[MBTcustom]

Today I shot some 230 grain 45acp boolits at a stack of phone books just for fun. They were made of a hard alloy (2% antimony and 2% tin), I found them sidways in the phonebook where they came to rest. my two friends shot various copper jacket boolits at the same stack (10mm, 45, 40S&W) all of those bullets "including the FMJ" mushroomed and stopped strait.
Interesting.

[DrB]

Bagtic, I believe I agree with most of your points...

All this I am sure was studied to death decades before I was born... I need to go back to the books on this one.

EDIT FOLLOWS/

After doing some more reading, some corrections/thoughts...
Any bullet design is going to cavitate on entry into a fluid/gel/flesh-like target from air.

Pretty much any bullet design is going to supercavitate (form a gaseous/vapor filled cavity that extends from the forward flow separation on the body nose and extends beyond the body) from a velocity probably a bit below 200fps and faster.

Center of pressure on a supercavitating body of revolution is going to be way towards the nose due to flow separation around the body.

Supercavitating bodies of revolution are generally statically very unstable for this reason... Given enough distance I would expect most any of them to tumble

I would expect the upsetting moments on a bullet in water instead of air to be very much greater in magnitude, and so I really doubt the spin of a bullet does much to keep it flying straight during penetration.

SC projectiles that are stable generally employ some means of contacting the cavitation bubble walls with fins or such on the aft body to maintain stability. Without a provision like this I don't see how your typical bullet design is going to penetrate with stability.

At first blush, I don't see how any conventional bullet design could be stable during penetration (but they don't have to be stable to penetrate straight if they stop much more quickly than they can tumble). My experience/perception is that swc type noses on fairly blunt bullets seem to penetrate and stop straight. Perhaps really what it comes down to is that the upsetting moment on a short fat bullet often doesn't provide sufficient tipping rotation rate to upset the bullet before it comes to a stop? Longer bullets penetrate further, and may just be prone to rotating more before coming to rest than short bullets, in part because the cp is so much further ahead of the center of mass, and an equivalent weight but longer bullet will travel a greater distance in penetration than a short counterpart?

This is the part I am particularly uncertain of (are there any blunt nose stable bullets)? How to reconcile that all these bullets should be very unstable in penetration with observations of recovered mushroomed bullets mushroom forward, unless they just didn't have time to flip, or there is a stability mechanism I'm not appreciating. Maybe we aren't talking about stable vs unstable bullets at all, but the difference between those that tumble very quickly and those that do so slowly enough it doesnt matter as they come to a stop or leave the target.

[Sonnypie]

Yeah I was going to do that, but Its still going to be pretty pricey. Another challenge I have is that I dont have a refrigerator big enough to set the stuff up. I'm going to see if it will set up on its own given enough time. I am also contemplating what is the best method to get a mold going. I would realy like to make ten blocks at once 6" X 6" X 36" at least.
Anyway thats the hold-up. Expense, and facilities.

If you make it out of a Jello you like, you could eat the left-overs of the testing.

Just a thought.... :lol:

[Grapeshot]

Geneva Convention covers only the treatment of Prisoners of War.

The Hague Convention forbade the use of expanding bullets in modern warfare.

[BAGTIC]

[QUOTE=Love Life;1506231]Your wrong bagtic. Pure and simple physics. The lighter nose slows down while the heavier back end maintins a stronger forward momentum. As the lighter nose slows down and the heavier base treis to continue, the base swings around giving you that wonderful tumble and yaw.

That is fact based off of years of established observation.

QUOTE]

The base does not swing around. The base continues forward while the nose swings around towards the rear.

The center of gravity is closer to the base than to the tip. The center of drag is closer to the tip because the part forward of the center of gravity is longer and provides more 'leverage' to push the nose around.

If you were to shoot an arrow backwards would you say the heavy end with the arrowhead caught up with and passed the fletched end.

The ends rotate around the center of gravity until the end with the most drag ends up down flow. It has nothing to do with axial motion. Why do you think weathervanes point into the wind?