What's Wrong with these pictures?

[pettypace]

Could it possibly be that tumbling is a better mechanism of wounding than expansion?

[Hardcast416taylor]

If I remember correctly tumbling of the bullet was a built in concept for the 55 gr. 5.56 round.Robert

[Edward]

Could it possibly be that tumbling is a better mechanism of wounding than expansion?

You stand a better chance of pass thru/blood trail in a hunting situation with expansion where as tumbling was used to incapacitate an opponent ,a way around the Geneva convention (hard ball) requirement

[JSnover]

Tumbling can produce a nasty wound but it's unpredictable. Too much is more of a yaw and your bullet may not hit the vitals.

[crankycalico]

It was proven that the webley 38 sw revolver with the 200 grain bullet tumbled through humans at decent ranges, thus was reduced in weight to keep from being considered illegal use.

British loved the tumbling bullet, but the tumbling normally messes up the amount of penetration youll get in tissue.

Don't forget the 55 grain fmj for 5.56x45 is supposed to shred apart at the cannelure to create the actual damage.

[quilbilly]

A few years back I did terminal ballistics tests with a 30/30 and a 160 RNGC boolit at an MV of 1550. The media was soaked, compressed phone books. The tumbling gave the most vicious wound channel of any I have tested before or since. The range was 40 yards. I definitely agree on the unpredictability of the tumbling of the boolits but if they stayed in the phone books, there was plenty of penetration.

[Outpost75]

.22 LR 40-grain LRN, .32 ACP hardball and .38 Special 158 LRN
ALL do the 180-degree flip after 5-6" penetration in bare gelatin and then continue base-first.

[Texas by God]

Mechanism of wounding? Sure. Emphasis on wounding- the purpose of the fmj from the beginning. Cut the nose of the fmj down to exposed lead and shoot that gelatin again and see what happens. We used "clip tip" .223, .308, 30-06 and 8x57 to hunt with as young men and they worked just fine on deer and coyote. They would mess a turkey up too much, though. Never had a stuck jacket, either. Tumbling is never a wanted thing on targets or game IMO.

[pettypace]

Thanks for all the replies. I don't feel I made very clear in my original post just what I was wondering about. Even so, your replies are helping me better focus my question.

First, I should say that the two pictures are from the Lucky Gunner series of tests of defensive handgun ammunition.



The picture on the left shows the results of five shots of 230 grain .45 ACP +P JHP that fully expanded. On the right, five shots of 124 grain 9mm that didn't expand at all, but instead did the "180-degree flip and continued on base first" (as Outpost75 so clearly describes it).

Now, I'm assuming that the obvious visible disturbance of the gelatin left in the path of the bullets somehow relates to the effectiveness of the round in a defensive situation. And given that assumption, it looks to me that the unexpanded and much lighter 9mm might be every bit as effective as the the fully expanded 45 bullet. Add to that an extra 6" of penetration for the 9mm and I'm beginning to wonder about some of the things I took as gospel for the last 40 years.

Looking through the Lucky Gunner data, it's not hard to find more examples of hollow point bullets that fail to expand but nevertheless leave a path of destruction in the gelatin by virtue of that "180-degree flip." So that begs the question of whether or not the ammo companies know what they're doing and actually designed in the 180-degree flip (as the Brits are said to have done with the .380/200) or were they just lucky that their unexpanded bullets don't just sail through a couple bricks of gelatin and keep on going?

[country gent]

A tumbling bullet may transfer energy better than a expanding bullet on long bullets The 200 grain 38 is a example getting the 38 bullet to expand to the almost 1" length of this bullet is hard but when side ways the length of the bullet is transferring energy. A good hollow point at full velocities may get to around .600 diameter mushroomed. Wound trauma is hard to predict since it varies with the individual "target"

One of the best Bowling pin loads we had for the wife's 357 was a 207 grn bullet at around 850 FPS. bullets didn't expand a lot but were almost always recovered sideways. The load like the British load was barely stable in flight and on impact stared tumbling. It was very effect at getting pins off the table.

[Texas by God]

Should we all switch to smoothbores?

[pettypace]

Should we all switch to smoothbores?

For short range defense? Yes! And make mine 12 gauge and 20" long.

But more to the point, I think "tumbling" is not the best description of what the 9mm rounds in the picture are actually doing. That's why I like the way outpost75 put it: "the 180-degree flip after 5-6" penetration in bare gelatin and then continue base-first." We're not talking here about a bullet that hits the target sideways as it might from a smoothbore or an ill-fitting bullet in a rifled bore. But rather a bullet that might be perfectly accurate (like a .22 LR or the .38 RN mentioned by Outpost75 above) until it enters the gelatin. Then it does the 180 flip and continues on base-first because that's the more stable orientation of the bullet. Even after the 180 flip, the 9mm's in the pictures above travel in a pretty straight line.

[Michael J. Spangler]

The answer to you questions are all in this link

https://drive.google.com/drive/mobil...3pWYVVJeGlGaFE

[crankycalico]

british engineers are said to have discovered that when their air craft dropped bombs in the early days of world war one, that the only way to have the impact fuze hit first was to have the fins on the other end. That way air flow, air speed(each end would have its own air speed, fins slower) would have fuze hit first.

The tumbling is simply centrifugal force in effect. Its how the british enfield rifle bullet, and its first compressed wood dust, then cast tin, that plastic tip section would hit a target and flip around doing ALOT more damage to the poor target.

However the 9mm bullets seem to NOT EXPAND.... somewhat of an issue with a "self defense cartridge" that cost 1.50$ each.

[GARD72977]

I shoot Gel a lot a work. That may look completely different if viewed from the top.

The gel makes the bullet react like it's hitting tissue. The gel does not react exactly like tissue (my opinion). We measure what the bullet does not what the Gel does.

[pettypace]

The answer to you questions are all in this link

https://drive.google.com/drive/mobil...3pWYVVJeGlGaFE

That will keep me busy. Thanks!

[pettypace]

I shoot Gel a lot a work. That may look completely different if viewed from the top.

I've wondered about that. Do bullets prefer to flip in the vertical plane so that the effect of the flip on the gel is most visible in the side view and less visible from the top view? Or is the plane of the flip rotating around the axis of flight?

[GARD72977]

Thats around 11% gel. The first shot will cause a break in the Gel. It looks like a lot of damage but it's not. I believe the channels from the added shots give the energy a place to dissipate.

Most of the time it's a tare in the Gel that is 1 dimensional. If you turn the gel there will be an angle where it's barley a visible line. Turn it 180 degrees and it looks like a massive wound cannel.

Im not an engineer just a tester with limited knowledge. What I think is wrong with using gel to test a wound channel is the large amount of unsupported mass. In any animal there will be bone close by. Just some thoughts.

All the information we record is about the bullet. Only thing really gel related is penetration.

[GARD72977]

I've wondered about that. Do bullets prefer to flip in the vertical plane so that the effect of the flip on the gel is most visible in the side view and less visible from the top view? Or is the plane of the flip rotating around the axis of flight?

I think it's random.

[KVO]

Agree with GARD72977. I have a few blocks of the Clear Ballistics product as used by Lucky Gunner in the above tests. It is useful for an apples to apples comparison of penetration and expansion between different bullets, but tends to create deceiving wound channels. My experience with it has been that once the velocity drops below about 750fps (my guesstimate) the gel won't accurately represent the permanent wound channel. I've had WFN boolits zip completely through two blocks, and even expanded HP recovered in the end of the second block nose first/ no tumbling and at some (velocity related) point the wound channel seems to disappear with nothing more than a pin hole behind the bullet. IME when a HP opens up asymmetrically or tumbling occurs penetration angle becomes unpredictable, sometimes with the bullet taking a turn and exiting the side/top/bottom of the block.