YAGT: OMG I love guns

[Nintendesert]

http://www.ar15.com/ammo/project/Self_Defense_Ammo_FAQ/index.htm

Good reading, thanks.

 

[HumblePie]

http://www.ar15.com/ammo/project/Self_Defense_Ammo_FAQ/index.htm

That is also a very good site. I used it a lot in my research on this subject. With modern caliber pistol ammo, the smaller bullets are fired typically at greater velocities to have them impart the same kinetic energy as the bigger but slower firing calibers. Meaning the penetration rates are going to be similar as well.

One thing I wanted to clarify with Hornady Critical, is that the little plastic insert helps in a significant manner when shooter a target with lots of loose clothing on. That little plastic nib helps the bullet penetrate the clothing before starting the deformation into the petal design of the hollow point. HST does a pretty good job of this as well. Speer GS not so much from some of the tests I saw. This image is of speer GD's after shooting through gel. Top row is gel only and bottom row is denim layers before the gel.

Speer going through clothing has significant petal integrity degradation. Other rounds are not so bad. I'm not saying speer is not a round that won't do the job. It can, will, and has. But are there other ammo types that are just a tiny bit better? Yes in my opinion based on various empirical evidence testing I've seen.

 

[irishScott]

Uhh, they used +p for the 45 acp.

It was 230gr +p 45 versus 147gr +p for 9mm. The wound channels for the two were exactly the same.

The only 230gr +p video on the site is Hornady XTP, and there's no XTP +P 9mm load to compare it too. Also there's no 147gr +p 9 videos at all, so I'm not sure what you're looking at.


Even if there were, comparing 9mm +P to .45 ACP +P is pointless, as SAAMI doesn't standardize the increase in ballistic performance across calibers, only stipulating an ~10% increase in pressure.

Since I'm supremely bored at the moment and wanted an excuse to try my new scanner, I even ran the math. Turns out 230 gr .45 +P actually has almost twice the gain over standard .45 as 115 gr 9mm +P gets over standard 9mm. Here it is in both Force and Energy:
Specs from SAAMI: http://www.saami.org/specifications_and_information/VelocityPressureData.pdf

Meanwhile, looking at the data on that site that is comparable, such as the Hydrashoks, and specifically the energy dissipation tables they include after each slow-mo video, it's clear that the .45 has a significant increase in energy transfer over the 9mm. The difference looks slight line-to-line, but taking the integral of that (which would be the sum of the energy) and accounting for the vertical scale, it would would prove to be a very significant difference.

Screenshots of the two rounds' data tables, note the difference in vertical scale:

"Nearly identical performance" not found. The difference may not be readily visible in the videos, but the numbers are there. If seconds matter and police are minutes away, Ft-lbs matter and organs are fractions of an inch away. If I can only put one round into someone, I'll take the .45 over the 9mm every time. And the net difference in energy transferred builds up if I land multiple hits.

 

[NuroMancer]

Hey Guys!

Been lurking this thread for quite a while and good news!

My License was approved yesterday (Live in Canada) and is on its way in the mail.

Picked up a 8gun combo safe on sale from Canadian tire for $200 bucks.

Now just need to start filling it, well, once the license actually arrives!

 

[exdeath]

Meh my handgun only exists so I can get to a rifle, that's it. Not going to argue about tenths of footpounds and fractions of inches.

Whatever I hit you with will be enough to give you pause while I reach for my rifle and prepare to liquify your organs.

Lets bitch about 9mm vs 40 vs 45 when you have a 150gr bullet zipping through at 3850fps

Also why the 40 hate? Ill put this out there , 40 = permanent CRUSH cavity, 9mm/45 = stretch cavity. Given that both go through you, would you rather be stabbed with a sharp needle or a blunt dowel? The truncated cone of the 40 is nasty with FMJ rounds. Penetration through cover is what the 40 was made for; 9mm not enough mass and 45 too slow and too big cross section.

 

[shortylickens]

Hey Guys!

Been lurking this thread for quite a while and good news!

My License was approved yesterday (Live in Canada) and is on its way in the mail.

Picked up a 8gun combo safe on sale from Canadian tire for $200 bucks.

Now just need to start filling it, well, once the license actually arrives!

This is gonna show my ignorance but how many guns are you allowed to own?

 

[NuroMancer]

This is gonna show my ignorance but how many guns are you allowed to own?

No restriction on amount but on type.

There are 3 classifications:
- Non-Restricted
- Restricted
- Prohibited

You can get a license for Non Restricted and Restricted fairly easily, Prohibited is far more difficult. The easist way is if you inherit them.

 

[irishScott]

Meh my handgun only exists so I can get to a rifle, that's it. Not going to argue about tenths of footpounds and fractions of inches.

Whatever I hit you with will be enough to give you pause while I reach for my rifle and prepare to liquify your organs.

Lets bitch about 9mm vs 40 vs 45 when you have a 150gr bullet zipping through at 3850fps

Also why the 40 hate? Ill put this out there , 40 = permanent CRUSH cavity, 9mm/45 = stretch cavity. Given that both go through you, would you rather be stabbed with a sharp needle or a blunt dowel? The truncated cone of the 40 is nasty with FMJ rounds. Penetration through cover is what the 40 was made for; 9mm not enough mass and 45 too slow and too big cross section.

How many world wars has .40 fought? 😛

But yeah, at the end of the day whatever we shoot, be it with .9, .40, .45, whatever, is likely going to die rather quickly. We're just debating about what kills faster than what.

 

[ManBearPig]

deleted

 

[irishScott]

Hey Guys!

Been lurking this thread for quite a while and good news!

My License was approved yesterday (Live in Canada) and is on its way in the mail.

Picked up a 8gun combo safe on sale from Canadian tire for $200 bucks.

Now just need to start filling it, well, once the license actually arrives!

Congrats! Any thoughts as to your first purchase?

 

[etrigan420]

No restriction on amount but on type.

There are 3 classifications:
- Non-Restricted
- Restricted
- Prohibited

You can get a license for Non Restricted and Restricted fairly easily, Prohibited is far more difficult. The easist way is if you inherit them.

Tavor.


Doooooo iiiitttttt.... 😀

 

[HumblePie]

TL;DR Cliffs:

1) Potential energy doesn't equate to transfer of that energy as trauma to a target.
2) What helps transfer energy that would be over penetration is spreading the energy over a large an area as possible while imparting as much inertia through spinning.
3) 9mm hollow points spread on average just about as wide as .45 acp
4) 9mm rounds spin twice as fast as .45 acp rounds.
5) .45 acp rounds have more potential energy, not a large amount more for what is needed to cause damage, but are inefficient at imparting that energy as trauma to a target with ballistic gel density.
6) Because .45 acp is inefficient as imparting it's greater potential energy as trauma to a target compared to 9mm which is more efficient, the wound channels and total damage caused tends to be the same.

----------------------------------------------------------------------


IrishScott,

What your math doesnt' tell you is the transference of kinetic energy over what area. It takes exactly 9 pounds of pressure to usually puncture human skin. If I apply that pressure through a needle point I'm going to poke skin If I apply that same pressure using a coke can I'm going to just get an indention in the skin. It pressure required for a coke can to puncture skin like a needle is significantly more since the can spreads the pressure out. So say it takes 500 pounds of pressure for a coke can to puncture the skin. You can compare that to 500 pounds of pressure to the needle. The can is going to do significant more damage than the needle at the same amount of force being applied.

Meaning it's not a complete static scenario. In math a .45 acp bullet moving a 800 fps is going to have more kinetic force than a 9mm bullet moving at 1059 fps. In ball ammo with the spread of force from the bullets being similar in cross section, the damage is going to be greater with the .45 acp. The difference is changing HOW that force is applied and how to harness more of that kinetic energy into the surrounding tissue to cause more trauma.

The problem becomes one of transference. Not potential energy. Both a 9mm and .45 acp round in ball ammo has enough force and energy to completely pass through and over penetrate the human body. Both will penetrate over 14" in human organ thickness ballistic gelatin. This is far enough to enter the gut of the average human and out the back and still keep going. Which means effectively that the potential kinetic energy the bullet has is not being fully imparted upon the target.

The goal of a defensive round is to cause as much trauma as possible with a single round. Ideally, you'll want all the potential energy to be imparted into the target. Which means have the bullet enter the target and stop just short of exiting. That is the most efficient usage of the round. With ball ammo, the only way to do that is to use less powder to impart less energy. But doing so doesn't make the wound any better just because the bull stops just shy of exiting the target because it lacks the power to push through. It's better to have the bullet expand to create larger surface area to put that pressure it has over a greater surface and cause more trauma. Just like the coke can example I talked about earlier.

The other key factor in imparting more energy into a target is spinning the tissue as it is being caught by the bullet. This imparts more inertia into the tissue causing it to pull tissue with it when being pulled on by the hollow point bullet.

And you have to consider the amount of force needed to cause trauma to a target in the first place. One can point to math and say, see .45 acp has X amount more potential energy than 9mm, but that doesn't mean squat when looked at in comparison to the energy needed to cause certain levels of trauma based on the material resistance of the target in question to energy being directed at it.

For math with an analogy to this would be the following. 1 grain is equal to 64.8 milligrams. So a 147 grain 9mm bullet weights in at 9.525 grams. A 230 grain .45 acp weighs in at 14.904 grams. For the standard F=MA equation that uses kg for mass, that is .009525 kg and .014904 kg. Using average velocities of non +p ammo from the previous testing site I link, the average 147 gr had an average muzzle velocity of 1000 fps or 304.8 m/s as recorded. It's a little faster than SAAMI specification, but within tolerances.

The average 230gr .45 acp was about 850 fps. Again a little fast, but in tolerances. So 266.7 m/s for the .45 acp.

Using handy dandy physics formula we can see that the 9mm is...

(.009525 kg)(304.8 m/s) = 2.90322 N

and the .45 acp is...

(.014904 kg)(266.7 m/s) = 3.9748968 N

But we already know that the .45 acp rounds have more energy. The little example math both irishScott and I did show that. The problem is how to impart all that energy into trauma on a target. The most efficient way is to impart as much force over an area as large as possible while spinning as fast as possible to provide inertia into the target. Both are key.

A 9mm by design is a bit more elongated. But lets look at the average spread of the hollow points that were recovered from the previous site throwing out the highest and lowest value as outliers. Which would be 0.356 inches for smallest and 0.821 inches for the biggest. We have an average spread of 0.640 inches.

Same thing with the .45 acp. Throw out the highest of 0.987 and the and the lowest outlier with a spread of 0.451 inches. Then the average was about 0.687ish inches for spread. Bigger spread but not as big as one might think considering the initial diameters of the bullet.

With the twist rate for a 230gr .45 acp at an average of 1 in 16" we get this for revolutions per minute using our current stats.

850 ft./sec X 1 rev./16 inches X 60 sec./min X 12 in./ft. = 38250 rev./min

The spin of the average 147gr 9mm with a 1 in 10" twist rate is.

1000 ft./sec X 1 rev./10 inches X 60 sec./min X 12 in./ft. = 72000 rev./min


So the 9mm is spinning twice as fast basically than the .45 acp. That spinning helps impart more kinetic energy to the target. I really don't know any formula to take the twist rate, ballistic gel density, potential energy and petal spread into account to determine potential trauma over a given length. I will state while the .45 acp has more potential energy, the fact that it barely spreads bigger than the 9mm as a hollow point and has a much lower spin rate means that less of it's energy is imparted as trauma onto surrounding tissue in a target than a 9mm with current design setups of modern hollow point bullets.

Remember, it's not how much potential energy that a caliber has, but how much of that energy it can impart on to the largest area possible of a target without wasting the energy. This is why real world testing of modern 9mm hollow points are very close in trauma caused to .45 acp hollow points. The difference as shown by real world testing proves that. The diameters of the wound channels created is about the same on average. Some 9mm shots have bigger wound channels and some have smaller.

 

[Phoenix86]

Just to throw another kink into the energy discussion, the human body is only so deep (or wide if you hit from the side) so the wound cavity in the first few inches where you're likely to hit a vital organ is more important.

Then you also have to factor in bones, which makes it even more difficult to calculate which means real world testing > gel testing >>>>> math.

 

[NuroMancer]

Tavor.


Doooooo iiiitttttt.... 😀

To answer all of the above questions.

a) I've really thought about the tavor
b) First purchase is just a good old shotgun for clays.
c) Ruger 10/22 and then maybe a kit for it?
d) For fun: a Russian SKS! + surplus ammo

Has anyone had expereince with or knows about Robertson XCR or their XCR-M?

It's pretty pricey but with the rules around uppers and how many semi autos fall under restricted it seems like a pretty nice tool.

 

[HumblePie]

Just to throw another kink into the energy discussion, the human body is only so deep (or wide if you hit from the side) so the wound cavity in the first few inches where you're likely to hit a vital organ is more important.

Then you also have to factor in bones, which makes it even more difficult to calculate which means real world testing > gel testing >>>>> math.

Yep, that's why it's not perfect, even with real world testing on static gels. Some testing is done with actual bone in the gelatin as well. Also the body isn't a uniform density and that is why good testers use a ballistics gel of non uniformed density as well to simulate the human body more closely. The old army standard to determine if a round was potentially lethal was to use a half inch of pine wood. It takes about 62 pounds per square inch of pressure to punch clean through a half inch of pine. So any round capable of that is potentially lethal to the old army standard. To put into perspective, a .22LR is capable of doing that out to over 400 yards away still. The problem is a .22lr is no longer accurate at that range though really.

Even a .22 short is going to put a hole through a pine board like that at 7 yards away. Making that still a potentially lethal shot. Meaning if it hits the right area it's going to one shot kill. Even if you don't hit the right area, if the person doesn't seek proper medical treatment in time they will die from any wound caused by a bullet. Just food for thought.

 

[Farmer]

Just to throw another kink into the energy discussion, the human body is only so deep....

So, the vertical axis of that chart is in units of Energy, and the horizontal axis is a depth. The only interpretation I have is the curve at a certain point in x is the amount of energy transferred exactly to that point in x.

Yeah, so looking at IrishScott's chart, it indicates the 9mm peaks faster in penetration depth, but the .45 is generally higher everywhere by roughly 10%. This factor would carry over the integration (that is, if the integrand is 10% higher but otherwise identical, so will the integrated value). I could conjecture that the slope on that curve for the 9mm is larger in magnitude everywhere, indicating that the 9mm transfers energy more efficiently per unit length when normalized to its starting energy. However, the 9mm starts with less energy, so, if my interpretation is correct, it is just a comparison between the higher starting energy of the 45 versus the high per unit length energy transfer efficiency of the 9mm.

Do you have the actual data for these tables, so we can integrate? Assuming frontal impact, the integration should be carried out to roughly 4-5", which I assume to be the average depth of a human torso.

HP:

I don't understand at all what you are attempting to say regarding the spin or whatever you mean by "imparting inertia". The energy transferred as a function of depth indicates energy transferred from both translational and rotational aspects of the bullet's total kinetic energy. To speak of efficiency as a function of distance, we need only look at integral of the plots irishScott posted up to some depth.

I shoot 9 but I'm open to other calibers.

 

[Phoenix86]

the integration should be carried out to roughly 4-5", which I assume to be the average depth of a human torso.

Even then you'd want to cut out the first roughly inch on both sides as that's fat/muscle. I think the sweet spot on the curve to check would be the 2-4" range. But I'll still fall back to my original point that you can only get so much out of the math, then it's time to do some actual tests to simulate real world as much as possible. Actual wounds can tell you a lot as well, but obviously this is harder to measure since it won't likely be replicated with different ammo types. 😉

Gel (with or without bone in it) can tell you a lot more than a chart and is obviously the standard for a reason. You can replicate distance, angle and compare vs many different types of ammo and weapons.

 

[clamum]

Yep, that's why it's not perfect, even with real world testing on static gels. Some testing is done with actual bone in the gelatin as well. Also the body isn't a uniform density and that is why good testers use a ballistics gel of non uniformed density as well to simulate the human body more closely. The old army standard to determine if a round was potentially lethal was to use a half inch of pine wood. It takes about 62 pounds per square inch of pressure to punch clean through a half inch of pine. So any round capable of that is potentially lethal to the old army standard. To put into perspective, a .22LR is capable of doing that out to over 400 yards away still. The problem is a .22lr is no longer accurate at that range though really.

Even a .22 short is going to put a hole through a pine board like that at 7 yards away. Making that still a potentially lethal shot. Meaning if it hits the right area it's going to one shot kill. Even if you don't hit the right area, if the person doesn't seek proper medical treatment in time they will die from any wound caused by a bullet. Just food for thought.

Absolutely. People talk about how shitty the .22LR cartridge is, but it does punch through that pine board over 400 yeards away (iraqveteran8888 on YouTube has a video demonstrating it). No, I will keep my 9mm pistol for concealed carry instead of a .22LR, but honestly, if I had good rounds for a .22LR carry gun I wouldn't feel scared carrying it thinking that I wouldn't be able to stop a threat. Shot placement is key and the round is very certainly lethal as hell, and you should be able to get accurate, multiple shots off due to the negligible recoil (assuming you've got a solid sight picture and all that jazz).

I would still recommend .380 ACP or a larger caliber for self-defense, but .22LR is nothing to laugh at.

 

[HumblePie]

Even then you'd want to cut out the first roughly inch on both sides as that's fat/muscle. I think the sweet spot on the curve to check would be the 2-4" range. But I'll still fall back to my original point that you can only get so much out of the math, then it's time to do some actual tests to simulate real world as much as possible. Actual wounds can tell you a lot as well, but obviously this is harder to measure since it won't likely be replicated with different ammo types. 😉

Gel (with or without bone in it) can tell you a lot more than a chart and is obviously the standard for a reason. You can replicate distance, angle and compare vs many different types of ammo and weapons.

Correct. And using materials such as denim and what not also help with performance determination of a specific caliber. Some bullets majorly deform and lose integrity too early. Others don't. The lost of petal spread and petal integrity as well as possible loss of inertia from spinning can make the wound channel much smaller than the same caliber round that doesn't have that problem. Materials used in the round also effect this.

That's why as a general rule, any pistol round .380 and up is going to cause roughly the same amount of damage using modern hollow point design.

 

[irishScott]

So, the vertical axis of that chart is in units of Energy, and the horizontal axis is a depth. The only interpretation I have is the curve at a certain point in x is the amount of energy transferred exactly to that point in x.

Yeah, so looking at IrishScott's chart, it indicates the 9mm peaks faster in penetration depth, but the .45 is generally higher everywhere by roughly 10%. This factor would carry over the integration (that is, if the integrand is 10% higher but otherwise identical, so will the integrated value). I could conjecture that the slope on that curve for the 9mm is larger in magnitude everywhere, indicating that the 9mm transfers energy more efficiently per unit length when normalized to its starting energy. However, the 9mm starts with less energy, so, if my interpretation is correct, it is just a comparison between the higher starting energy of the 45 versus the high per unit length energy transfer efficiency of the 9mm.

Do you have the actual data for these tables, so we can integrate? Assuming frontal impact, the integration should be carried out to roughly 4-5", which I assume to be the average depth of a human torso.

HP:

I don't understand at all what you are attempting to say regarding the spin or whatever you mean by "imparting inertia". The energy transferred as a function of depth indicates energy transferred from both translational and rotational aspects of the bullet's total kinetic energy. To speak of efficiency as a function of distance, we need only look at integral of the plots irishScott posted up to some depth.

I shoot 9 but I'm open to other calibers.

Was going to post a response, but this is pretty much it. While the spin/twist of the bullet can affect energy transfer, judging from the plots it's a fairly negligible advantage, likely due to the .45's lesser initial velocity and increased surface area. What matters is how much energy is transferred inside the human torso, not how it's transferred there. From those plots, the .45 would appear to be superior in this regard.

I'm willing to admit that 9 is a more efficient cartridge in terms of damage per $$$, material, and perhaps ammo capacity depending on the gun, but round-for-round the .45 is consistently superior IMO.

I wish I had the data, but those plots are just screenshots of youtube videos. I poked around the site but couldn't find the raw data anywhere. I'd also like to know how they got their data, as I didn't see any sensors hooked up to the ballistic gel blocks in the video.

As others have pointed out ballistic gel tests are an approximation at best. They don't take into account bones, the varying density of internal organs, or bullet path/angle. IIRC the FBI put their standard at 12 inches in part because penetration in a human body is consistently less than penetration in gel.

So we need real-world testing, and that's where the .45 has its century in the military. Not that 9 is a bad round, but it's hardly developed the legacy of the .45. Granted, it hasn't really had the chance. .45 was used in two world wars and Vietnam. 9 was used in the Gulf, Iraq and Afghanistan, and I doubt pistols are used much in Afghanistan.

 

[BladeVenom]

In the 9mm vs. .45 debate the answer is 10mm.

 

[shortylickens]

 

[etrigan420]

ouch.

 

[irishScott]

In the 9mm vs. .45 debate the answer is 10mm.

In the handgun caliber debate the answer is a shotgun.

 

[etrigan420]

In the handgun caliber debate the answer is a shotgun.

Get a Taurus Judge and have both! D: