General Categories > General Firearm Discussion
9mm
GreyGeek:
--- Quote from: OnTheFly on September 30, 2014, 10:23:57 PM ---I am too tired (and possibly not bright enough) to understand everything you just wrote. However, I think I get the gist of what you are saying. My only comment would be that, to take it to an extreme as extremes tend to emphasize what is really happening, if the bullet never penetrated or barely penetrated, how much do the waves matter? The more the bullet penetrates without passing straight through, the more that energy is dissipated into the gel/body.
Or did I completely not understand?
Fly
--- End quote ---
AWick's physics is spot on.
The speed of the bullet makes all the difference as to why a handgun round makes holes out of which the target bleeds to death, and a rifle bullet blows large holes in the target, created by shock waves which transverse the entire body cavity regardless of where the bullet strikes. Thus, an HV rifle round hit in the shoulder or pelvis is as lethal as a hit in the center of mass because the shock wave from extremity hits does lethal damage to the center of mass.
Adding more energy to a bullet only increases the amplitude of the transverse pulse wave, not the frequency or the speed of the pulse wave. For a given force, the more elastic the medium (a body vs a block of wood) the less resistance to the force, which allows a greater amplitude to the pulse wave. The energy of the pulse wave being proportional to the square of the amplitude, a quadrupling of the amplitude of a wave is indicative of a 16-fold increase in the amount of energy.
Because the pulse wave is transverse (perpendicular) to the path of the bullet, and the more energy the bullet delivers to the body the greater the amplitude of the pulse wave, the impact of the bullet will never "blow someone off their feet", or move them horizontally backwards, like blowing them out of a window, as many Hollywood movies show. The conservation of momentum explains why. Being conserved, the momentum before impact and the momentum after impact of the bullet are the same, or afterwards less, any losses due to conversion into heat.
So, 300m/s * 0.008Kg + 100Kg*0m/s = 100.008Kg* Xm/s. Solve for x, the "backward" velocity of the target.
Since even 9mm or .40 caliber handguns bullets are not powerful enough to deliver pulse wave energies even close to those of a rifle bullet, shot placement is all important. Unless hit in the brain, spine or heart the target will not be immediately stopped and may not quickly die or die at all. Ergo, the more holes in the target the more likely a shot will hit a vital organ or, the target will loose blood quickly enough to lapse into unconscionableness.
Otherwise, carry a rifle hidden in your pant leg and pretend to be Chester.
Ghost:
--- Quote from: GreyGeek on October 01, 2014, 09:30:17 AM --- ...the target will loose blood quickly enough to lapse into unconscionableness.
--- End quote ---
Unconscionableness? ??? :)
JTH:
One of the issues with this way of thinking of pistol caliber bullet weight/size and pistol caliber velocities is that pistol calibers and rifle calibers are significantly different in terms of velocity, and therefore the elastic stretching that occurs in pistol calibers is significantly different than in rifle calibers.
Simple way of saying it: In general, pistol calibers simply aren't going fast enough for the temporary cavity to actually damage anything. Rifle calibers ARE, and the temporary cavity is sufficient to actually damage tissue. (SFG already said this in a clear fashion.)
There are a number of good research reports out there about wound ballistics, but most of them sum up to:
--with modern JHP ammunition, with respect to efficacy in terms of stopping bad guys other than barrier penetration, there is no significant different in pistol calibers from 9mm up through .45. (And yes, that includes .357sig and 10mm.)
--there is a world of difference between pistol calibers and rifle calibers in terms of wound ballistics damage, unless you are talking about incredibly small rifle bullets moving fairly slowly for rifles compared to .38Super major loads (moving quickly for pistols).
--Temporary cavities look really cool in slow motion in ballistics gel. However, in human tissue, pistol temp cavities don't "stretch" tissue enough for damage.
--the concepts of "energy dumping," damage-as-a- function-of kinetic-energy, and momentum calculations all seem to have fairly little to do with reality, according to the research.
This, unfortunately, is incorrect:
--- Quote ---That energy dissipation directly relates to the amount of tissue that experiences extreme trama and the severity of said trama...
--- End quote ---
Nope. Wish it was, because wound ballistics would be a lot more simple, and the caliber wars would be over. :)
--for pistol calibers, physiological stops are functions of accuracy. Psychological stops aren't functions of calibers.
--for rifles, things are different.
And just because, a video of a slug into ballistics gel in slow motion, because we know that slugs are just the end-all, be-all of self-defense:
:)
GreyGeek:
--- Quote from: Ghost on October 01, 2014, 09:45:37 AM ---Unconscionableness? ??? :)
--- End quote ---
Ya. I argued with my keyboard but it wouldn't listen! ;)
sjwsti:
--- Quote from: jthhapkido on October 01, 2014, 10:39:02 AM ---One of the issues with this way of thinking of pistol caliber bullet weight/size and pistol caliber velocities is that pistol calibers and rifle calibers are significantly different in terms of velocity, and therefore the elastic stretching that occurs in pistol calibers is significantly different than in rifle calibers.
Simple way of saying it: In general, pistol calibers simply aren't going fast enough for the temporary cavity to actually damage anything. Rifle calibers ARE, and the temporary cavity is sufficient to actually damage tissue. (SFG already said this in a clear fashion.)
There are a number of good research reports out there about wound ballistics, but most of them sum up to:
--with modern JHP ammunition, with respect to efficacy in terms of stopping bad guys other than barrier penetration, there is no significant different in pistol calibers from 9mm up through .45. (And yes, that includes .357sig and 10mm.)
--there is a world of difference between pistol calibers and rifle calibers in terms of wound ballistics damage, unless you are talking about incredibly small rifle bullets moving fairly slowly for rifles compared to .38Super major loads (moving quickly for pistols).
--Temporary cavities look really cool in slow motion in ballistics gel. However, in human tissue, pistol temp cavities don't "stretch" tissue enough for damage.
--the concepts of "energy dumping," damage-as-a- function-of kinetic-energy, and momentum calculations all seem to have fairly little to do with reality, according to the research.
This, unfortunately, is incorrect:
Nope. Wish it was, because wound ballistics would be a lot more simple, and the caliber wars would be over. :)
--for pistol calibers, physiological stops are functions of accuracy. Psychological stops aren't functions of calibers.
--for rifles, things are different.
And just because, a video of a slug into ballistics gel in slow motion, because we know that slugs are just the end-all, be-all of self-defense:
:)
--- End quote ---
^This^
Thanks JT, you just saved me some time today.
Can anyone tell me exactly what part of a human ballistic gel is supposed to represent? Does it simulate a solid organ like the liver? Or a hollow organ like the stomach? Maybe lung tissue? Maybe the bladder (empty or full)? You cant ignore the widely varying organ characteristics that exist inside real human beings and how that effects energy transfer.
Kinetic energy + target tissue characteristics = wounding potential.
- Shawn
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version