Flat Nose Bullets

[openbook]

OP, I think that, even with no deformation, the meplat causes hydraulic shock not caused by a round nose or even pointed boolit. The effect of a pointed or round nose on a soft target is more of a "parting," like a knife parts material either side of the blade, without destroying it. In contrast, the abrupt impact of the flat meplat causes a hydraulic shock that reverberates through surrounding tissue. You may have seen Beta O'Rourke sometime in the past few years complaining about Armalite Rifles that shoot 5.56 NATO, he said something about how the round travels at such an incredibly high speed that it causes hydraulic capillary damage, exploding blood vessels and other soft tissue in the vicinity of the wound. The flat nose also causes hydraulic shock, but not because of extreme speed on a diagonal angle (the ogive); instead it's because of moderate or even low speed with a perpendicular impact.

The following is from an article by Glen E. Fryxell discussing an all-purpose SWC bullet. The bullet was tested by a butcher who needed to process large animals. Note that he describes the type of wounding inflicted and also points out that the nose was not deformed.

"Frontal brain shots typically liquefied the brain (“turned it to mush” were Carl’s exact words), exploded the upper neck joint of the spine, and then penetrated under the hide of the neck for several inches (for about 15” of total penetration). Not surprisingly, recovered bullets showed no expansion, only engraving from the rifling and nose scarring. He also reports that this ammo is noticeably quieter than the .38 ammo he had been using (undoubtedly because of the light powder charge)."

Others can certainly correct me on some of my terms. Hopefully this is helpful to you. I'm not an expert but I have a passing acquaintance with fluid dynamics from a prior career.

[44MAG#1]

I have a few LBT molds. Spent many minutes talking to Veral years ago on the phone.

[stubshaft]

I have had the pleasure of knowing and talking to Veral Smith of LBT bullets over the years. His book "Jacketed Performance of Cast Bullets" is a must read. I have shot and killed a lot of animals in my career with a wide variety of bullet designs both J word and cast. When I began hunting hollow points were "the" bullet to use and would wreak death and destruction on anything it touched. Thirty-nine years or so ago, I had the opportunity to talk to Veral and buy one of his 45-300 LFN molds for my FA-83 454 Casull. That gun has accounted for hundreds of dead hods and sheep, and the deadliness of a wide meplat bullet was attested to. At that point I gave up on HP bullets and converted solely to wide meplat bullets.

Since that then I have ordered, cast and shot a variety of LBT molds in a number of calibers. They range from the Long Flat Nose, Wide Flat Nose to the Ogival Wadcutter with a few spitzers thrown in for paper punching. I have used them in wide variety of calibers, and they ALL exhibit the effectiveness of the design.

This is NOT an advertisement for his molds, but rather an endorsement of the efficiency of a large meplat bullet.

[justindad]

Does the Meplat really do much?

Imagine you are a high diver standing over a swimming pool. Do you want to make yourself small or large?

[44MAG#1]

So, in summation, the larger the Meplat the more cavitation and "Slap", my term that sure isn't a technical or scientific term, the target receives be it living tissue or water jugs or any other medium?
A larger Meplat at a given velocity gives more cavitation and "Slap" over a smaller Meplat with a given caliber bullet at a given weight?
Providing the bullet is NON DEFORMING bullet that doesn't readily change the Meplat shape when striking, and penetrating the medium being living tissue, water jugs or other mediums that isn't concrete, steel, rock etc., etc..
So in a 45 Auto one would rather have a .330 Meplat than a .250 Meplat with a given bullet.
This again, is with a NON DEFORMING bullet.

[TurnipEaterDown]

The formula given in post #18 for cavitation is: Cavitation (in soft tissue) ---> CAV(FN) (inches) = Impact Velocity (fps) x Meplat Diameter (inches) / 225 - 0.725
So, yes.
In my experience, I also find that the edge form of the meplat matters too: The sharper the edge at the transition from the meplat to ogive, the better. Also, it is best that the meplat is truly flat.
Some mold makers make the meplat slightly rounded (convex) and the edge of the meplat with a rather generous radius transition to the ogive. Both these actions are done in my understanding to drop the bullet easier from the mold when casting. For performance, I really feel that these actions should be held to an absolute minimum.

[44MAG#1]

The formula given in post #18 for cavitation is: Cavitation (in soft tissue) ---> CAV(FN) (inches) = Impact Velocity (fps) x Meplat Diameter (inches) / 225 - 0.725
So, yes.
In my experience, I also find that the edge form of the meplat matters too: The sharper the edge at the transition from the meplat to ogive, the better. Also, it is best that the meplat is truly flat.
Some mold makers make the meplat slightly rounded (convex) and the edge of the meplat with a rather generous radius transition to the ogive. Both these actions are done in my understanding to drop the bullet easier from the mold when casting. For performance, I really feel that these actions should be held to an absolute minimum.

I have both his first and second printing but could only find this one.
The formula is on page 101. In his second printing he says the same DV can be gotten by VelocityXMeplat Diameter/4. He is correct on that.

[justindad]

The sharper the edge at the transition from the meplat to ogive, the better. Also, it is best that the meplat is truly flat.

This is absolutely true and is easily demonstrated in mechanical stress analysis. When an object is clamped for stress-strain curve measurement, the edges of the clamp create the highest stress, which is why dog-bone samples are narrow in the middle - so the small section is stressed higher than the clamped section. Pull apart a piece of toilet paper - the tear almost always occurs where your fingers are gripping the paper. Now pull it apart by grabbing the paper with pliers instead of your fingers - sharper edge. If you understand the physics behind stress concentration factors (i.e. stress can be more than force divided by area), the sharp meplat edge theory is obvious.
*
Using pressure film to analyze gasket pressures will also support the sharp meplat theory. The film will overhang the gasketed area, and the perimeter of the metal parts will show a significantly higher pressure than the middle region.
*
Now what if the meplat is so large that acceptable penetration fails? What if the high diver hits ice and fails to break through?

[pettypace]

So, in summation, the larger the Meplat the more cavitation and "Slap", my term that sure isn't a technical or scientific term, the target receives be it living tissue or water jugs or any other medium?
A larger Meplat at a given velocity gives more cavitation and "Slap" over a smaller Meplat with a given caliber bullet at a given weight?
Providing the bullet is NON DEFORMING bullet that doesn't readily change the Meplat shape when striking, and penetrating the medium being living tissue, water jugs or other mediums that isn't concrete, steel, rock etc., etc..
So in a 45 Auto one would rather have a .330 Meplat than a .250 Meplat with a given bullet.
This again, is with a NON DEFORMING bullet.

Two questions:

1) How (if at all) is the "cavitation" related to the "temporary cavity" that we hear so much about with respect to gelatin testing and that Fackler drew and labeled in his wound profiles?

2) I understand that "Slap" is not a technical term. But it must relate to some physical phenomenon. Is "Slap" something the target receives just at the instant of bullet impact? Or does the bullet keep "Slapping" the target through the entire penetration path?

[pettypace]

I have both his first and second printing but could only find this one.
The formula is on page 101. In his second printing he says the same DV can be gotten by VelocityXvelocityXMeplat Diameter/4. He is correct on that.

Do you have an extra velocity there you didn't intend?

[44MAG#1]

Two questions:

1) How (if at all) is the "cavitation" related to the "temporary cavity" that we hear so much about with respect to gelatin testing and that Fackler drew and labeled in his wound profiles?

2) I understand that "Slap" is not a technical term. But it must relate to some physical phenomenon. Is "Slap" something the target receives just at the instant of bullet impact? Or does the bullet keep "Slapping" the target through the entire penetration path?

1. If a flat nose bullet does not cause more trauma then all of the people that believe that they do, by the overwhelming amount of shooter using them, have been duped by snake oil salesmen pushing Flat nose bullets all these years in various uses. Now do you want all of them to admit they have been duped?
2. Slap , I would say slap is a term i used for a whoopin on the intended target. With a bullet raging through tissue i would say it would be like a good beat down.

[44MAG#1]

Do you have an extra velocity there you didn't intend?

Yes I do. Thank you for pointing it out.

[500aquasteve]

I shot these 400 grain Woodleigh loads through my 4” S&W 500 destroying the sandbag. Don’t have my load logbook here for details, but used H110



As seen below, the jacketed flat soft nose can also expand to incredible proportions

[pettypace]

1. If a flat nose bullet does not cause more trauma then all of the people that believe that they do, by the overwhelming amount of shooter using them, have been duped by snake oil salesmen pushing Flat nose bullets all these years in various uses. Now do you want all of them to admit they have been duped?
2. Slap , I would say slap is a term i used for a whoopin on the intended target. With a bullet raging through tissue i would say it would be like a good beat down.

OK... I think I understand your answer (#2, above) to my question about "Slap." It sounds like the same thing Hatcher had in mind when he wrote about "Bullet Effect and Shock Power" (chapter 12 of Textbook of Pistols and Revolvers).

But I don't understand why you get all snippy with me (#1 above) when I asked about "cavitation."

So, I'll ask the same question again:

What is the relationship (if any) between the term "cavitation" as used in this thread and the term "temporary cavity" as commonly used in gelatin testing and as drawn and labeled in Fackler's wound profiles?

[44MAG#1]

OK... I think I understand your answer (#2, above) to my question about "Slap." It sounds like the same thing Hatcher had in mind when he wrote about "Bullet Effect and Shock Power" (chapter 12 of Textbook of Pistols and Revolvers).

But I don't understand why you get all snippy with me (#1 above) when I asked about "cavitation."

So, I'll ask the same question again:

What is the relationship (if any) between the term "cavitation" as used in this thread and the term "temporary cavity" as commonly used in gelatin testing and as drawn and labeled in Fackler's wound profiles?

Temporary cavity is cavitation. Just because the temporary cavity is temporary doesn't mean it isn't a cavity. It is a cavity at the time it happens that is the reason it is called TEMPORARY CAVITY. Cavity, cavity, cavity as in temporary CAVITY. Now the remaining cavity is a cavity such as in REMAINING cavity. The spray of and crushing of tissue that causes the permanent cavity, in my mind, is a direct cause of the temporary cavity.
While one shrinks back, although not all the way, there is enough cavity to cause a crushing and ripping that causes a permanent cavity.
The relationship is CAVITY. One is TEMPORARY and one is PERMANENT hence the relationship is cavity. With something speeding through tissue could you have one without the other?
A surgeon isn't taking a scapel and gently cutting out a hole. It is caused by a projectile speeding and coursing through the tissue.
Again are all the believers in the flat nose bullets been wrong all the time by believing in them?
Maybe a product of snake oil salesmen?
I have a question for you, if, in your Charter Arms 44 Special you had only TWO CHOICES of bullets, a 245 grain ROUND NOSE and a 245 grain FLAT POINT with Meplat diameter of .300 inches at 700 fps which one would you choose for self defense.
ONLY the TWO choices I gave you and why? I bet you would choose the round nose.

[pettypace]

Again are all the believers in the flat nose bullets been wrong all the time by believing in them? Maybe a product of snake oil salesmen?.

Sounds like you're looking for a straw man to bad mouth meplats. But (to borrow a phrase from Bob Dylan) it ain't me, babe. For me it's full wadcutters all the way down.

[44MAG#1]

Sounds like you're looking for a straw man to bad mouth meplats. But (to borrow a phrase from Bob Dylan) it ain't me, babe. For me it's full wadcutters all the way down.

I asked you a simple question about what you would choose out of the two bullets I mentioned.
Cant answer that question?? I bet most on here could

[jrayborn]

I so badly want to say the flat point but am pretty concerned that i might develop some give-a-darn about what anyone else thinks.

[44MAG#1]

Better to just keep it to yourself. That way no one will poke fun.

[Good Cheer]

To illustrate how flat noses behave, this was from penetration tests with a .41 caliber revolver* using round flat nose, semi-wadcutter and wadcutter bullets fired into stacked paper that had been soaked in water until the binder gelled and the fibers were separating.
Wide flat noses tend to stack flesh, temporarily making the stacked flesh a part of the projectile as well as imparting a more violent sideways velocity to the perimeter. That's why the #41026 penetrated half as far as the others.

*.36 caliber Pietta replica 1858 Remington modified to use .41 caliber molds.