Two-Projectile Loads in Snubby for Self-Defense

[Michael J. Spangler]

How do you know that? We aren't talking about the innervation of the tongue or fingertips. It seems to me blowing a major bone to smithereens might hurt quite a lot. Similarly, liver kicks and punches are devastating, so why wouldn't a bullet to the liver cause extreme distress?

Agreed. Stopping is about hitting the off switch. The CNS which works. Pain doesn’t stop. If that were the case a 12 gauge shell full of #9s peppering the whole body would do the trick every time.
CNS is the only way to drop someone quickly.

[Good Cheer]

Reminds me of Adam discussing a sword duel with Hoss.
How wide is that pig sticker? Oh, 'bout 3/4 inch.
How wide are the bullets in your revolver? A little less than 1/2 inch.

Increasing damage matters.
Quadcutters in a dedicated Security Six rebored to take trimmed back 30-30 brass would just be the cat's meow.

[Bill*B]

Gunsmith Roy Dunlap served in the Ordnance Corps during WWII. He though the little Italian M 1934 in .380 was a pretty good piece, stating in print that "the point nearly every pistol argument misses is that a hit with any bullet above a .22 rim fire will slow a man down enough from whatever he is doing - running away, running toward you, or shooting at you - to give you time enough to put in a fatal hit or hits. And I do not think anyone will argue that the smaller calibers are not easier for the unpracticed man to handle."

[pettypace]

Here's a chart from MacPherson's Bullet Penetration book:

Attachment 245774

The numbers are what MacPherson calls "wound trauma incapacitation mass." I call it the hamburger factor. Generally speaking, it's supposed to be the grams of crushed tissue in the permanent wound cavity. But MacPherson puts a little spin on the numbers and that requires some explanation:

For the JHP numbers, the calculation is only done for penetration up to about 14". That's the "JHP maximum" in the chart. The "JHP 12 inch" number is a little lower than expected because MacPherson figures an average penetration of 12" would mean about half the shots would penetrate less than the FBI minimum. The "JHP 10 inch" number is considerably lower than a simple calculation because MacPherson figures that with an average penetration of 10", very few shots would meet the FBI minimum penetration of 12".

The bottom two lines of the chart are for non-expanding, non-tumbling bullets. MacPherson spins these numbers, too: First, he figures there are really only two choices -- sharp-edged cylinders and everything else. There are slight differences among all the other bullet shapes but the wadcutters (NOT semi-wadcutters) are 50% better than all the rest at crushing tissue. And second, MacPherson assumes that any non-expanding, non-tumbling bullet from a worthy cartridge will penetrate at least 18" and his calculations are done only for the first 14" of penetration.

Given all that explanation, MacPherson concludes "Table 11-6 shows that properly designed JHP bullets have a maximum wound trauma rating (in the absence of barriers) that is substantially higher than can be achieved with non-expanding bullets."

So, here's the kicker for a two-projectile .38 Special load: My last few gel tests with the 105WC/105WC combination have consistently shown the average penetration of both projectiles to be more than 18". Then, according to MacPherson's chart, each projectile should have a "wound trauma incapacitation mass" of 24. That would give the two-projectile load a total hamburger factor of 48 grams of crushed tissue per shot.

I don't expect folks to rush to the LGS to trade in their Glock 21 for a S&W 442. After all, 14 times 55 is way more than 5 times 48. But still, 48 is more than 34 and ten chances at the Fitz Luck Target is better than five chances.

[pettypace]

At last week's Snubbyfest we tried some .44 Special duplex loads I cooked up for a shooting buddy's recently acquired Charter Arms Bulldog. Preliminary results are very encouraging!

Here's a picture of the gel test:

Attachment 249944

This is the second of two ammo can size gel blocks. So the bullets had already penetrated 11" of gel before entering this block from the left. I fired five shots -- ten projectiles. One escaped. The remaining nine are more or less visible in the picture. The actual penetrations were 14", 14", 14.25", 14.5", 15", 15", 15", 15", and 16". (AVG: 14.75")

NOTE: At the time of this test I thought there was an inch-to-inch correspondence between penetration in Clear Ballistic gel and in validated 10% ordnance gel. I've since learned that this is not true. Roughly speaking, bullet penetration will be less in 10% ordnance gel than in C-B gel. Recent testing has shown that penetration in real gel would likely be only about 80% of what I measured above -- say, 11.8" average. So, what looks to be ideal penetration above, is more likely just shy of FBI minimum penetration.


I had my chronograph set up and the close clustering in the gel block was undoubtedly the result of surprisingly consistent velocities for the five shots: 565 ft/s, 566 ft/s, 567 ft/s, 568 ft/s, and 570 ft/s. (AVG: 567 f/s)

I fired the last ten rounds at a target -- 5 shots at 10 yards and 5 at 20 yards.

Attachment 249945

At five yards with normal ammo, the Bulldog had been shooting low and left. So I was holding at 3 o'clock on the black. All the white shots came from the five rounds at 20 yards.

[pettypace]

While I was mightily impressed with the duplex loads in the Charter Arms Bulldog, the real crowd-pleaser at last week's Snubbyfest was an Auto Ordnance Thompson which everyone was excited to shoot. The owner of the Thompson provided an ample supply of hot JHP .45's with a big warning label on the box: "For Thompson Only!"

My turn with the Thompson included a shot at the gello. To the delight of the onlookers, that hot JHP .45 slug lifted the two blocks of gel a couple of feet into the air and onto the ground. Once the debris had been cleared off the gel, we saw that the expanded .45 slug had penetrated about 20" in a perfectly straight line. Later, when I dissected the gel, I found perfectly symmetric expansion to an average of 0.550" and no fragmentation. Pretty impressive.

But then I began to wonder just how the permanent wound mass from the hot .45 JHP out of the Thompson compared to that of the .44 duplex loads from the Charter Arms Bulldog. Here are the calculations which are just the volume of the permanent wound cavity "cylinder" times a bullet shape factor (0.82 for an expanded JHP and 1.00 for a WC) times the density of tissue (about 16 grams/cubic inch):

For the Thompson: 3.14*(0.55/2)^2*20*0.82*16 ==> 62 grams.

This agrees pretty closely with the 55 grams listed in MacPherson's chart (see post #204 above) for the "JHP Maximum" for a .45 ACP.

For the Charter Arms duplex load: 3.14*(0.43/2)^2*14.75*1.00*16 ==> 34 grams.

Although MacPherson's chart doesn't include a .44 caliber column, it's easy enough to estimate: The .44 has about 50% more cross-sectional area than a .38. So the 24 grams MacPherson lists for a 9mm WC would scale up to 36 grams for a .44 WC. So the calculated 34 grams is close to MacPherson's estimates.

But wait... I forgot one minor detail. The Charter Arms Bulldog was firing two of the those projectiles -- each crushing 34 grams of tissue for a total of 68 grams.

So, at least in terms of permanent wound mass, it looks like the little Charter Arms Bulldog with some pretty docile duplex loads is in the same league as the Thompson firing some pretty fierce .45 JHP loads.

[pettypace]

The previous Bulldog gel test had an average velocity of 567 f/s (for 5 shots) and an average penetration of about 15" (for the 9 projectiles remaining in the gel). After consultation with the owner of the Charter Arms Bulldog, we agreed to try to ease the velocity up to 600 f/s and hopefully push the penetration a little closer to the FBI recommended maximum of 18". Here are the results.

Attachment 250372

Velocity: 610, 626, 632, 636, 637 ==> AVG: 628 f/s
Penetration: 16.25, 16.75, 17, 18, 18.5, 18.5, 19.5, 20.25, 21.5 ==> AVG: 18.5"

NOTE: At the time of this test I thought there was an inch-to-inch correspondence between penetration in Clear Ballistic gel and in validated 10% ordnance gel. I've since learned that this is not true. Roughly speaking, bullet penetration will be less in 10% ordnance gel than in C-B gel. Recent testing has shown that penetration in real gel would likely be only about 80% of what I measured above. So, the 18.5" average penetration reported above, would likely correspond to about 15" in validated 10% ordnance gelatin.


This is the velocity and penetration that we hoped to achieve. But the first gel block shows a problem that I may have overlooked in the previous gel test. Here's a picture of the entrance holes from this test:

Attachment 250369

Note that only four of the five shots show even the slightest separation of the duplex pairs and the shot at the upper right shows no separation at all. I doubt anyone knows exactly what bullet separation would optimize the incapacitation. But I'm pretty sure that ten distinct entrance holes and ten distinct bullet paths beats five and five. For what it's worth, there were eight distinct bullet paths by the time the bullets exited the first gel block.

For these first two tests, I had loaded the two wadcutters base-to-base with the front bullet flying with the button nose forward and back with button nose aft. For the next round of testing, I loaded the two wadcutters nose-to-base. Some are loaded with button noses facing forward and some with the buttons facing to the rear. I'm expecting to see better entrance separation and wouldn't be surprised to see the base-forward bullets cutting bigger entrance holes.

[rking22]

Quick question, at what distance were the bulldog loads fired into the gel? Sorry if I missed it.

[pettypace]

Quick question, at what distance were the bulldog loads fired into the gel? Sorry if I missed it.

I'm afraid I'd make a sorry scientist. Didn't even measure the distance, let alone record it. But I had a chronograph between the muzzle and the target. And the chronograph balks when I get too close. So, I'd guess about 3 to 4 yards.

[rking22]

Thank you. I would be interested in the results at ,maybe, 15 yards to compare to the “near contact” distance. I would think the spread could get problematic at 25+, but that is an assumption.. I am not one who considers a 2 inch snubby only useful at “get offa me” distance. They can be unexpectedly accurate when the one behind the trigger knows how!

[pettypace]

I would be interested in the results at ,maybe, 15 yards to compare to the “near contact” distance. I would think the spread could get problematic at 25+, but that is an assumption.. I am not one who considers a 2 inch snubby only useful at “get offa me” distance. They can be unexpectedly accurate when the one behind the trigger knows how!

I didn't take pictures of the 20 yard targets we fired with the current Bulldog load. But they were about the same as the target in post #205 above which was fired with a slightly lighter load.

I agree that the snubby can be surprisingly accurate. And even with the two-projectile loads, accuracy is more than adequate for any likely civilian self-defense need.

In the Textbook of Pistols and Revolvers (pp 174-5) Hatcher describes the "receiver and forearm rest" they used at Springfield Armory to sort out 1911's for the National Matches. Maybe tomorrow I'll make a receiver and forearm rest for the Middleboro Matches. At 25 yards from rest, I wouldn't be surprised to see my 442 or my buddy's Bulldog keep a cylinder full of duplex loads in the black of a 50 yard slow fire target.

[justashooter]

still have a bag of 60 grain .358 wadcutters that stack 3 in a 38 special case over 5 grains of unique from time to time and print into 2" or so at 25 yards. lotsa' fun on a target range with retentive shooters on the next bench.

[pettypace]

Here's a picture of today's get test with two projectile loads in the Charter Arms .44 Bulldog. I've been loading the two 150 grain NOE wadcutters base-to-base, but for today's test, they were loaded with both bullets heading base forward. As usual, this is the second of two ammo can size gel blocks. So the projectiles entered this block from left to right after already penetrating 11" of gel in the first block.

Attachment 250484

Five shots. Velocity: 586, 609, 612, 615, 632 ==> AVG: 611 f/s

Ten hits. Penetration: 15.25, 16, 16.25, 16.5, 16.5, 16.75, 17.25, 18, 19.75, 19.75: AVG: ==>17.2"

NOTE: At the time of this test I thought there was an inch-to-inch correspondence between penetration in Clear Ballistic gel and in validated 10% ordnance gel. I've since learned that this is not true. Roughly speaking, bullet penetration will be less in 10% ordnance gel than in C-B gel. Recent testing has shown that penetration in real gel would likely be only about 80% of what I measured above. So, the 17.2" average penetration reported above, would likely correspond to about 14" in validated 10% ordnance gelatin.



I also fired the same two .38 Special +P "calibration" rounds I've used in previous testing. These never made it out of the first gel block. The 90 grain Hornady Critical Defense Lite at 944 f/s penetrated 8.5" and the 95 grain Winchester Silvertip at 921 f/s penetrated 10.5".

Accuracy at 25 yards from a rest was disappointing. But I was encouraged when a relatively new shooter fired this target from 7 yards. He fired deliberate double action with a two hand hold -- 10 shots, 20 hits on the paper. At this range, the pairing of the bullets is obvious.

Attachment 250487Attachment 250489

[35remington]

Not reviving unnecessarily.

By any measure the second projectile in this biprojectile load should not penetrate as well as it does being a disk with horrible section density. Wide and light. Yet they did 16 inches.

Drafting effect, certainly.

https://m.youtube.com/watch?v=pvUAlbkQbuA

[pettypace]

By any measure the second projectile in this biprojectile load should not penetrate as well as it does being a disk with horrible section density. Wide and light. Yet they did 16 inches.

Drafting effect, certainly.

https://m.youtube.com/watch?v=pvUAlbkQbuA

Once the disk turns sideways it's gonna have more sectional density and a better gel-piercing shape. Maybe that's enough to account for 16" - 18" of penetration.

But that video makes me wonder what STB would say about two 150 grain .44 caliber wadcutters penetrating to 16".

[35remington]

Could be, but I would have thought they would have veered worse than they did if so since they are so wide and comparatively thin. Maybe not what I presumed. Would be interesting what would have happened if the disk 45s were fired singly without a preceding bullet anyway. How much of the travel is through a draft cavity? Perhaps a very slo mo video while also determining how far the disk strayed from the first bullet’s path could answer that.

I would suppose he hasn’t gotten around to testing any 44 Special ammo yet, let alone the speciality or boutique types.

[35remington]

The Reader’s Digest version is it would have a better gel piercing shape.

The drafting bit still ought to be run down if possible. What is worth pondering is whether it occurs to the same degree in an actual body with the connective tissues and other structures present. I suspect it may not.

[pettypace]

If I may respectfully suggest something...

Actually, the sectional density (having units in ppsi or pounds per inch²) of a wadcutter (right cylinder) will always decrease in its lateral striking orientation.

For example, if we compute the respective "lateral attitude" (striking a target sideways) and "nose-forward attitude" (striking a target normally) sectional density (whose units are expressed in pounds/inch²) of the 150-grain wadcutter presently under discussion (diameter = 0.429"), even if we increase the wadcutter's mass by several times, the lateral attitude sectional density of wadcutters is always going to be less than that of a wadcutter that is oriented in a nose-forward 'normal' striking attitude:

—a 150-grain wadcutter having a length of 0.362" and a diameter of 0.429" would have a "lateral" SD of 0.137915314 ppsi
—a 150-grain wadcutter having a length of 0.362" and a diameter of 0.429" would have a "nose-forward" SD of 0.148247969 ppsi

—a 300-grain wadcutter having a length of 0.724" and a diameter of 0.429" would have a "lateral" SD of 0.137915314 ppsi
—a 300-grain wadcutter having a length of 0.724" and a diameter of 0.429" would have a "nose-forward" SD of 0.296495939 ppsi

—a 450-grain wadcutter having a length of 1.086" and a diameter of 0.429" would have a "lateral" SD of 0.137915314 ppsi
—a 450-grain wadcutter having a length of 1.086" and a diameter of 0.429" would have a "nose-forward" SD of 0.444743908 ppsi

As can be seen by the computed values, even as wadcutter mass and length increases, the lateral SD remains constant while the nose forward SD increases linearly.

If anything, the reason for increased penetration (not related to drafting within a temporary cavity) of a wadcutter hitting gelatin sideways would be a function of diminished C_D (drag coefficient) which is C_D = 0.833333 for nose-forward penetration of right cylinders having a L/D ratio ≥ 1.5 and C_D ≈ 0.30 — 0.35 for right cylinders striking a target laterally (that is, sideways) where R_e is > 10⁵ — 10⁶.

Hope this helps.

But what if we do the same calculations for a 75 grain .44 caliber "wadcutter"?

—a 75-grain wadcutter having a length of 0.181" and a diameter of 0.429" would have a "lateral" SD of 0.137915314 ppsi
—a 75-grain wadcutter having a length of 0.181" and a diameter of 0.429" would have a "nose-forward" SD of 0.0741 ppsi

Now we have a "wadcutter" which will increase its SD when in the lateral orientation. And that's closer to the 70 grain .45 caliber disk in the "Shooting the Bull" video under discussion.

[pettypace]

The drafting bit still ought to be run down if possible. What is worth pondering is whether it occurs to the same degree in an actual body with the connective tissues and other structures present. I suspect it may not.

Yes, indeed!

So, here are some pondering points:

1) In the recent .44 Bulldog tests, I've been focused (maybe fixated is closer to the truth) on the second ammo can of gel and pretty much ignored what happened in the first gel block. That's a mistake. I'm guessing that the closer the two-projectile entrance holes, the more "drafting" we'll see.

2) Here, the term "drafting" is actually just a synonym for "penetration-more-than-predicted-by-the-Schwartz-expedient-equation." Unfortunately, "drafting" sounds like an explanation that we don't really have. But "penetration-more-than-predicted-by-the-Schwartz-expedient-equation" can actually be measured. Maybe that measurement will lead to a better handle on your second point about the likely real world physiological effect of a two projectile load.

3) Maybe a partial clue to the likely real world physiological effect can be found in the notion of "effective diameter" that I used in the tumbling bullet thread. For example, from the last three tests with the Bulldog:

From post #205 an average velocity of 567 f/s should penetrate 11.3" but actually penetrates 14.75" giving an effective diameter of 0.37"
From post #207 an average velocity of 628 f/s should penetrate 12.2" but actually penetrates 18.50" giving an effective diameter of 0.35"
From post #213 an average velocity of 611 f/s should penetrate 12.0" but actually penetrates 17.20" giving an effective diameter of 0.36"

So, maybe to some extent the two-projectile .44 load would have a real world physiological effect of two .38 caliber projectiles. For example...

4) It might make more sense to calculate something like permanent wound mass for a two-projectile load using the effective diameter instead of the actual diameter. That might avoid eating the free lunch that P&P warned didn't exist way back in post #7.

5) On the other hand, I don't see how we can discount the depth of the observed penetration. If some vital target requires, say, 14" of penetration, it's hard to imagine one of those .44 slugs that penetrated 16" not reaching that target.

6) Also, I wouldn't expect any mysterious diminution of the effect on bone as a result of two projectiles running in close proximity at virtually the same time. That's not to say that I would expect two 150 grain .44 WC running side-by-side to have the same effect on bone as a single 300 grainer.

7) Surprisingly, discussion of the most obvious characteristic of a two-projectile load -- namely the increased probability of hitting a vital target with a well-placed shot -- has been all but ignored throughout this thread.

[pettypace]

Thanks for all that, Chuck. As usual, the deeper you get into something, the more questions arise. I'm gonna let some of those questions congeal while I take a poke at how two-projectile loads increase the probability of a "vital hit."

Here's a target fired by a relatively new shooter at Snubbyfest a few weeks ago. I'm using it here just to illustrate a point.

Attachment 251014

For the sake of discussion, let's assume that the X ring represents a "vital" target area and that any hit touching that area would quickly incapacitate the bad guy -- a "vital hit." And with that assumption we might ask what percent of trigger pulls produced a "vital hit"?

If the target had been fired with regular ammo, the answer would be simple: 10 trigger pulls produced 3 X's, so 30%.

But it the target had been fired with two-projectile loads (as it actually was) it's not quite so simple. We don't know for certain whether the 3 X's came from two trigger pulls or three. If two trigger pulls produced the 3 X's, then 40% of the trigger pulls produced a "vital hit." But it's possible that the 3 X's came from three trigger pulls --in which case 60% of the trigger pulls resulted in a "vital hit."

Obviously, this is a simple example of a past event which may or may not provide much insight into future events. But with the usual caveat of other things being equal (which, of course, never are) it's clear that two shots per trigger pull beats one.