This might be a little "out there" for OSR, but I thought it was an interesting question, one I don't have an answer to.

First, the back story: A while back, some of my fellow nerd-types and gun nuts were sitting around discussing the efficacy of various calibers against two-legged predators. A guy we know refuses to carry anything short of .44 Magnum, while the rest of us are more satisfied with 9mm, .40, and .45. One of our group hypothesized that .44 Magnum, while plenty effective, might suffer from overpenetration, which is then kind of a waste of energy and recoil (not to mention size and weight of the gun). We thought this was an interesting question, and being a bunch of douchebag nerds, we decided to compile some ballistic gel penetration data from a variety of sources and see how everything stacked up.

We wound up coming up with a decent model that approximates ballistic gel penetration for pistol calibers based on bullet mass, diameter, and muzzle velocity, and is actually surprisingly accurate (.44 Magnum, by the way, will occasionally overpenetrate in fast loadings, from the data we collected, but it's not as bad as we expected).

So, we come to the question: A few weeks ago a guy I know was considering a revolver for home defense, and, like I've seen a thousand times before, gravitated immediately toward the Taurus Judge, because, in his words, "It's a fucking shotgun that you can carry concealed!" :shaking:. I pointed him toward the Box o' Truth (http://www.theboxotruth.com/docs/bot41.htm) tests which show that the only human-effective load out of the Judge is .45 LC, which you can find in much nicer and more reliable revolvers.

This guy, his taste in revolvers aside, isn't dumb, and immediately asked me a question I couldn't answer: why is it that 000 buck doesn't penetrate well out of the Judge, but we trust the smaller, lighter 00 buck to penetrate, and even overpenetrate, out of a 12-gauge? Admittedly, out of a long barrel, the load will be moving a lot faster than out of the Judge's snubby barrel, but in our earlier comparisons between different calibers we found velocity played a role, but not enough of a role to compensate for the difference.

To try and figure this out, I punched 00 buck at what I thought was a reasonable velocity (anywhere between 1100 and 1500 ft/sec) into the very same equation that predicted pistol calibers so very well, and came up with only 5 - 7 inches of penetration into ballistic gel, much less than the actual measured 14 - 20" I was able to find.

Wise minds of PBB, what gives?

TL;DR: Why does buckshot kick so much ass?

I'm going to guess your equation is a good fit for JHP that are expanding, but not for shot (or FMJ).

I doubt you will even see 1100 fps out of a .410 judge shell, while 1300-1500 out of a 28" 12ga is plausible. As far as your program, the 000 buck 70gr and will carry a bunch less energy than a 147gr, 230gr or even 240gr pistol round. weight + speed == kinetic energy, which == penitration.

Punch in a 90gr .380 going 900fps and see what it looks like.

#0000 Buck 5.51 g (85 gr.) 9.40 mm (0.380")
#000 Buck 4.54 g (70 gr.) 9.14 mm (0.360")
#00 Buck 3.49 g (53.8 gr.) 8.38 mm (0.330")
#0 Buck 3.18 g (49 gr.) 8.13 mm (0.320")

Here is another box of truth page with 12gauge buckshot.

http://www.theboxotruth.com/docs/bot3_2.htm

It doesn't penetrate as well as pistol ammo.

"Lessons learned:
1. Notice that the #4 and #1 Buck penetrated 6 boards. In previous tests, 9mm, .45 ACP, and M-193 out of an AR all penetrated all 12 boards.

The 00 Buck penetrated 8 boards, but was stopped by the 9th. Still not as much penetration as the pistol or rifle loads.

The slug penetrated all 12 boards."

Interesting chart from another site;
http://www.shotgunworld.com/bbs/viewtopic.php?f=7&t=154308&start=0
http://www.tridentconcepts.com/alumni/Portals/0/NTForums_Attach/1620135812171.jpg

The best measure of kinetic energy delivered from a bullet is grainfeet/second (mass x distance over time). If a bullet stays in it's intended target, it delivers 100% of that energy. If it exits (overpenetrates) the difference in entrance and exit speed, as a percentage of entrance speed, is the percentage of energy delivered.

That's why JHP's are more effective, because they tend to stay in the target, delivering 100% of their energy.

Sectional Density. Not that relevant to comparing shotgun pellets to each other, but certainly relevant to comparing conical "standard" bullets of similar design. i.e a 150 gr .308 to 140gr 6.5 mm at similar velocities.

I imagine Google + Kennedy + magic bullet should find something.

I appreciate the responses guys! Let's take these one-by-one.

I'm going to guess your equation is a good fit for JHP that are expanding, but not for shot (or FMJ).

The equation is set up to handle JHP vs. FMJ by looking at their expanded diameter. I've got a little checkbox that, if checked, multiplies the diameter of the projectile by 1.5, which I found reasonable based on some expansion studies I found. I wish it was as simple as that, I really do.


I doubt you will even see 1100 fps out of a .410 judge shell, while 1300-1500 out of a 28" 12ga is plausible. As far as your program, the 000 buck 70gr and will carry a bunch less energy than a 147gr, 230gr or even 240gr pistol round. weight + speed == kinetic energy, which == penitration.

Punch in a 90gr .380 going 900fps and see what it looks like.

#0000 Buck 5.51 g (85 gr.) 9.40 mm (0.380")
#000 Buck 4.54 g (70 gr.) 9.14 mm (0.360")
#00 Buck 3.49 g (53.8 gr.) 8.38 mm (0.330")
#0 Buck 3.18 g (49 gr.) 8.13 mm (0.320")

I ran the .410 at 750 - 850 fps, based on chronograph results I found (which, incidentally, caused quite a bit of damage to the chronograph, thanks to the Judge's rifled barrel flinging the shot all over the place :laughing:).

Part of the reason this is complicated is that my study did not show that doubling the muzzle velocity would double penetration. In fact, based on comparisons between .45 ACP and .44 Magnum, which were the closest pair I could think of with a serious velocity spread, doubling the velocity gets you about 1.4x the penetration.

So, in the case of the .410 Judge vs. a 12-gauge, the .410 is moving along at ~700 fps and the 12-gauge, for argument's sake, is moving at ~1400 fps, twice the speed. What we find, according to the equation, is the .410 penetrates 4.2", which is very close indeed to the Box o' Truth's measured 4.5". The 12-gauge penetrates 5.6". This seems small to me.

As requested, I ran 90 gr. .380 through the simulator at 900 fps, and found penetration of 7.7", which sounds very reasonable to me.


Here is another box of truth page with 12gauge buckshot.

http://www.theboxotruth.com/docs/bot3_2.htm

It doesn't penetrate as well as pistol ammo.

"Lessons learned:
1. Notice that the #4 and #1 Buck penetrated 6 boards. In previous tests, 9mm, .45 ACP, and M-193 out of an AR all penetrated all 12 boards.

The 00 Buck penetrated 8 boards, but was stopped by the 9th. Still not as much penetration as the pistol or rifle loads.

The slug penetrated all 12 boards."

Interesting chart from another site;
http://www.shotgunworld.com/bbs/viewtopic.php?f=7&t=154308&start=0
http://www.tridentconcepts.com/alumni/Portals/0/NTForums_Attach/1620135812171.jpg

This is particularly interesting. I know that from the lack of mass of 00 buck, it's not going to penetrate as well as a heavier bullet - this is obvious. I wish he had conducted the test with a water box or ballistic gelatin, because I don't have a drywall-to-flesh conversion factor handy :laughing: .

This is making me very curious, because if buckshot really is as poor of a penetrator as my study is showing, I'm beginning to have some reservations about its efficacy.

However. The chart you show indicates that the buckshot is penetrating about 16" or so, which is more than twice what my best estimates show it penetrating. This right here is exactly what I'm trying to figure out. The 9mm shows about 20" of penetration in their model. I'm showing a max of about 17.5" with +P that's really cooking, which is fairly comparable. What's not comparable is the buckshot wounding profile.

The best measure of kinetic energy delivered from a bullet is grainfeet/second (mass x distance over time). If a bullet stays in it's intended target, it delivers 100% of that energy. If it exits (overpenetrates) the difference in entrance and exit speed, as a percentage of entrance speed, is the percentage of energy delivered.

That's why JHP's are more effective, because they tend to stay in the target, delivering 100% of their energy.

That's actually precisely the point behind my study, to be able to evaluate analytically the penetration characteristics of various ammunition. The FBI, I believe, considers effective ammo to penetrate 12 to 18 inches in ballistics gel - any less than 12" is not enough penetration to be considered 100% effective, and any more than 18" will tend to overpenetrate, thus wasting valuable energy.


Sectional Density. Not that relevant to comparing shotgun pellets to each other, but certainly relevant to comparing conical "standard" bullets of similar design. i.e a 150 gr .308 to 140gr 6.5 mm at similar velocities.

I imagine Google + Kennedy + magic bullet should find something.

I actually studied this extensively in an earlier model, by adding sectional density and ballistic coefficient into the calculations. It turned out that with the exception of very low ballistic coefficient projectiles (highly-tuned boat tail bullets), the distinction could be summed up with whether or not a bullet was a HP or not. The distinction between FMJ ball, shot, and .40-style flat-nose profiles, for example, given identical masses, diameters, and velocities, was less than 5%, not enough to even bother calculating. This may come into more effect if I were to consider rifle bullets as part of the study, but for the time being, I'm leaving rifles out, though I think my mathematics should work effectively for lower-powered rifle rounds, up to about .223. Past that, and the rifle bullets start doing weird stuff like fragmenting, which is damn hard to calculate.

Thanks for all the responses, guys. The chart given above is exactly what I'm trying to figure out. Everything I can find on buckshot penetration shows it's roughly comparable to a light 9mm in penetration (12" - 15"), whereas the calculations show more like 6" - 7". This discrepancy is what I'm trying to solve.

For some scholarly ballistic info, I would spend some time here.

Terminal Ballistic Information (http://m4carbine.net/forumdisplay.php?f=91)

And here.

Firearms Tactical (http://www.firearmstactical.com/wound.htm)

Just off the top of my head, I'd say that buckshot comes with it's own lead blockers. The first pellets may soften the tissue or even open up a temporary cavity for the following pellets to travel down.

Quick Q about buckshot in a judge. Wouldn't thr rifling in the barrel play hell with a shot pattern? I know the barrel is shorter than piggy's pecker, and it's strictly a close range set up, but even still, isn't it a bit of a red herring?

This is a good read.

Hydrostatic shock (http://en.wikipedia.org/wiki/Hydrostatic_shock)

Quick Q about buckshot in a judge. Wouldn't thr rifling in the barrel play hell with a shot pattern? I know the barrel is shorter than piggy's pecker, and it's strictly a close range set up, but even still, isn't it a bit of a red herring?

It may open up a little bit, but the barrel is so short I doubt it matters.

http://www.theboxotruth.com/docs/bot43.htm

There's box o truth on shot through a rifled slug barrel. It opened up, but that's with a 28" long barrel, I can't imagine that the judges 4" does anything to it.

For some scholarly ballistic info, I would spend some time here.

Terminal Ballistic Information (http://m4carbine.net/forumdisplay.php?f=91)

And here.

Firearms Tactical (http://www.firearmstactical.com/wound.htm)

Thank you. The second one is actually where I got my initial data from which the equation in my study is based.

For those of you who are mathematically-inclined, I used caliber (expanded diameter, in the case of HP bullets), velocity, and bullet mass as variables against penetration data and performed a multivariate regression to find a best-fit surface in four dimensions (caliber, velocity, mass, & penetration). This equation for this surface (which, obviously, based on the buckshot penetration data shown above in the diagram, needs some modification) is what I'm performing my calculations against.


Just off the top of my head, I'd say that buckshot comes with it's own lead blockers. The first pellets may soften the tissue or even open up a temporary cavity for the following pellets to travel down.

This is an interesting thought. It would begin to explain why the Judge, with only three pellets does not penetrate well at all, but a 12-gauge, with 9 - 15 pellets at 00 size does penetrate effectively. This, of course, will imply that the closer one is to the target, the better the penetration expected, independent of velocity. Perhaps I can perform some calculations in my model in the case of multiple shot to find the probability of a pellet opening a temporary cavity for the pellet behind it based on number of pellets and distance from the target. Interesting...


Quick Q about buckshot in a judge. Wouldn't thr rifling in the barrel play hell with a shot pattern? I know the barrel is shorter than piggy's pecker, and it's strictly a close range set up, but even still, isn't it a bit of a red herring?

Yeah, it does, at least according to my research. The Box o' Truth found that with birdshot, the pattern is really open even at ten yards. This site (http://mcb-homis.com/judge/index.htm) tested the judge at 40 ft (13.3 yards) and found an absolutely wild spread of shot for Winchester ammo, and an only somewhat wild spread with Sellier and Bellot. He did find better penetration than the Box o' Truth, but I still wouldn't trust it.


This is a good read.

Hydrostatic shock (http://en.wikipedia.org/wiki/Hydrostatic_shock)

This is the direction I will be moving with the study after I have the equation stabilized and reliable. My argument will be essentially that the caliber of choice will be the biggest, fastest load (that the shooter can handle) that provides acceptable penetration. For instance, based on my brief study, I would choose .45 ACP over .44 Magnum on a human target because I've found .44 will overpenetrate about half the time, which means an exit wound and a projectile that is still traveling down the shot path. How much energy that projectile has will vary, but it's still a little scary. According to my study, .45 ACP is plenty of round, without that risk.

I would think that the wild spread of the shot has more to do with the very short 4" barrel than it does the rifling. I'm sure the rifling has some affect, but I doubt it has much affect given the 4" barrel. I'm also assuming that since it also fires .45LC that the effective choke is probably open cylinder.

In short, I would assume that The Judge is pretty much a .45LC revolver than can also fire .410 shotgun shells. It isn't really designed to give optimal performace with .410, but it can safely fire them.

IMO, the only thing I'd use the .410 for in this gun is snakes, rodents, and general blasting shit just for fun. I wouldn't plan on using it in any defensive manner.