Two-Projectile Loads in Snubby for Self-Defense

[pettypace]

Have you considered running an actual Monte Carlo simulation using anatomically super-imposed targets and marking/tracking the history of each "pair" or "triple" after they are fired?

It might be a bit of a stretch to call it "an actual Monte Carlo simulation," but before getting sidetracked by my buddy's .44 Bulldog, I was planning some tests to see if the two-projectile .38 snubby loads would produce a lower shots-to-vital-wounds ratio than an "equivalent" single-projectile control load. The planned tests would go something like this:

1) Following MacPherson's lead (Vital Wound Analysis, page 268 of Bullet Penetration) define a "vital wound" as any shot hitting a 2" x 20" white paper strip stapled vertically over a B27 target with the bottom of the strip level with the bottom of the B27 10 ring.

Attachment 251066

2) The two-projectile "test" loads would consist of two 105 grain wadcutters loaded to about 625 f/s in .38 Special cases.

3) The single-projectile "control" loads would consist of a 200 grain Lee RFN bullet also loaded to about 625 f/s in .38 Special cases. Some fiddling with the control load might be needed to ensure that they were at least as accurate as the two-projectile loads and that both loads shot as close as possible to the same point of impact and had more or less the same recoil.

4) Before shooting the test target, shooters could "sight-in" by taking a few sighting shots on a bullseye target set at the same range as the test target.

5) Shots on the test target would be fired in groups of four, with two of the two-projectile "test" cartridges and two of the single-projectile "control" cartridges loaded "randomly" into the cylinder. Shooters, of course, would try to maximize hits on the "vital wound" strip aiming where they thought best based on their results on the sighting target.

6) Because all the test loads would be WC bullets and all the control loads would be RFN bullets, which loads made which hits would be obvious on the paper.

7) Only hits on or cutting the 2" x 20" paper strip would be counted, except that very close shots with the RFN control bullets would be "plugged" with a .45 caliber plug to at least partly compensate for the expansion of JHP bullets. Any control load shot that plugged "in" with the .45 plug would be marked on the paper strip and scored as a "vital wound."

8) After each four-shot test, the 2" x 20" paper strip would be removed and saved as a hard copy of the test. Info such as shooter's name, distance, maybe the time to fire the four shots, etc., could be recorded on the strip for posterity.

This seems simple enough that it might actually get done and maybe even "prove" something. My guess is that at close ranges, say 2 to 10 yards, the two-projectile load would produce a significantly lower shots-to-vital-wounds ratios for both novice and experienced shooters. Beyond 10 yards, I wouldn't be surprised to see good shooters do better with a single-projectile load. But who know?

[pettypace]

Bleeping cold and windy at Snubbyfest today. But I did get a chance to follow up on the suggestion 35remington made long ago that I test the light for caliber wadcutters loaded singly to the same velocities as they have in the two-projectile loads.

So, today I fired nine of the NOE 150 grain WCs into the gel with an average velocity of 608 f/s and average penetration of 14". Two weeks ago, a two-projectile load with an average velocity of 611 f/s left nine WCs in the gel at an average penetration of 17.2".

By now, the once unexpected extra penetration of the duplex loads has become commonplace and no longer so mysterious. Given what we've all seen of slow motion temporary cavities, it seems obvious that two projectiles going through at the same time would have an easier go of it. But it can't be all gravy. If the two projectiles have an easier go of it, it may well be that they are not crushing the same amount of tissue as if the same two projectiles were traveling singly. For that reason, I expect that I have over-estimated the permanent wound mass (or hamburger factor) in some of my posts above. Sorry about that.

[35remington]

That somewhat to substantially addresses my concerns about the adequacy of such a load. Could a double helping of the same be considered controllable in the Bulldog?

[pettypace]

That somewhat to substantially addresses my concerns about the adequacy of such a load. Could a double helping of the same be considered controllable in the Bulldog?

By "double helping of the same" do you mean a quick "burst" of two shots, each with a single 150 grain wadcutter payload? Or do you mean a two-projectile load with two 150 grain wadcutters in the case?

Either way, I would consider it controllable in the Bulldog -- especially with the big rubber grips on the current versions. Of course, the 300 grain payload is a considerably bigger handful. But no where near as nasty as a full-blast .357 from a snubby.

[35remington]

Since this thread is about two projectile loads that is what I meant.

[pettypace]

Since this thread is about two projectile loads that is what I meant.

This target is a good indication of how controllable the Bulldog is with the two 150 grain .44 wadcutters at just over 600 f/s.

Attachment 250487Attachment 250489

The target was fired double action at 7 yards by a guy who just started shooting a couple months ago. Although he's fired a variety of handguns at Snubbyfest, I'm sure he doesn't have more than a couple hundred rounds under his belt. And most of that has been with relatively light loads.

[superior]

Your Honor, ladies and gentlemen of the jury... The defendant wasn’t satisfied with ammunition that was capable of killing a horse.... no... he had to go down in his basement and manufacture his own special brand of KILLER BULLETS !!!

[35remington]

Not relevant in any known case.

Back to topic, please.

[pettypace]

The source of the discrepancy between the predicted/mTHOR-computed penetration depths versus actual penetration depths reported in CBG arises from the fact that the expedient equation (that is, the modified THOR armor penetration power law) power law variable, α , was fitted to the only two valid test mediums extant (that is, water and 10% ordnance gelatin) that have markedly differing densities and yield strengths than that of the CBG product. The CBG product, an elastomer plasticized by Paralux 701 paraffinic process oil, has also experienced differences in its formulation over time meaning that test results in one iteration of the CBG formula are unlikely to produce test data that is comparable in other iterations of the CBG formula.

Finally, according to the Bernoulli pressure equation, P = ½ρV² , the density of CBG, which is about ρ = 865 kg/m³, results in less pressure to drive expansion of the projectile (when it does occur) meaning that expanded diameter is less than that seen in water or 10% nominal concentration ordnance gelatin. Lower density also means less resistance to projectile momentum and correspondingly lower decelerative force acting upon the projectile. Lower decelerative forces acting upon the projectile means that penetration depth is greater in the CBG product than that observed in either water or 10% nominal concentration ordnance gelatin. The only way in which to properly modify the m-THOR power law would be to fit the variable, α , to the CBG product by shooting several hundred of each projectile configuration into CBG and fitting the α variable to the CBG test data. Given the historical fluctuation of the CBG formulation, I am not sure that this would be a worthwhile pursuit.

Thanks for that clarification. I may have seen the Brassfetcher video you linked to earlier in your post. But if I did, I'm afraid I ignored the obvious conclusion in (mis)using the m-THOR equation to (over)estimate the permanent wound mass of some of these two-projectile loads. I should review the thread and edit the offending posts to highlight those over-estimates.

Despite its failings, the allure of the Clear Ballistic product remains its low cost and ease of preparation and storage, all relative to real 10% ordnance gelatin. While it may not be "good enough for government work," it serves my purposes -- all the more so if I keep your cautionary notes in mind.

[walnut1704]

The most interesting multiple projectile project I ever saw was detailed in some decades old gun magazine. The writer took a Colt Lawman MK III (a common gun in those days) and bored the chambers all the way through....he reamed out the throats. He then used .357 Maximum brass to load his multiple projectile ammo. I wish I could find that article.

These days most of us would be reluctant to do that to a gun...but there's always an extra cylinder.

[PHyrbird]

I see there's a lot of math & stats here, impressive. Also impressive is the result of 6 410 shells from a Governor. Three perhaps four holes at 7-10 yards in a dinner plate for every hammer drop. Lots of terminal energy, not for long range.

[pettypace]

Truly, sir. It is worth noting that the Clear Ballistics synthetic gel product is not used by any reputable ammunition manufacturers, military, LE or other governmental enforcement agencies to T&E their ammunition that I am aware of. When those entities want to do that, they go with the "real McCoy"— validated 10% ordnance gelatin. For "entertainment value" I s'pose that the Clear Ballistics gel product appeals for its clarity and knowing its limitations as you do, heck.....why not?

Maybe there's a relatively simple workaround by which penetration depths in CB gel can be translated into results in the "real McCoy". I'll use some testing already done above to illustrate what I have in mind:

In post #225 I reported the following:

So, today I fired nine of the NOE 150 grain WCs into the gel with an average velocity of 608 f/s and average penetration of 14". Two weeks ago, a two-projectile load with an average velocity of 611 f/s left nine WCs in the gel at an average penetration of 17.2".

The problem is that both penetration depths, the 14" for the single projectiles and the 17" for the two-projectile loads, were measured in Clear Ballistic gel and have no scientifically established connection with the FBI 12" - 18" requirement. The tests give strong indication that there's some kind of "drafting" going on with the two-projectile load penetrating deeper than the same projectile fired singly at the same velocity. But neither the 14" nor the 17" (or even the 3" difference between them) can be directly related to the FBI 12" - 18" requirement. For all we know, the same tests fired into validated 10% gel might have given only, say, 9" for the single projectiles and 11" for the two-projectile loads, rendering the two-projectile load useless for self-defense.

But we do have the mathematical models of Messrs. MacPherson & Schwartz. Using, for example, the mTHOR model from Quantitative Ammunition Selection by the Schwartz I can easily calculate that the predicted penetration of a .44 caliber, 150 grain wadcutter at 600 ft/s in validated 10% ordnance gel is about 11.8". A quick interpolation using the "Cylinder Bullet Penetration Depth" graph from MacPherson's Bulet Penetration confirms that estimate.

In other words, a single .44 caliber, 150 grain wadcutter at 600 ft/s does not quite meet the well-established FBI 12" - 18" penetration requirement and should be considered barely (or not quite) adequate for self-defense. The fact that it penetrates 14" in Clear Ballistic gel is irrelevant. But we have now learned that for this bullet at this velocity, 14" in the CB gel equates to just shy of 12" in the 10% ordnance gelatin. That's good to know.

Of course, the two-projectile load penetrated deeper than 14" in the CB gel and undoubtedly would penetrate deeper than 12" had they been fired into validated 10% ordnance gel. But how much deeper we don't really know because the extra 3" of penetration measured in CB gel does not directly translate into 3" in validated 10% gel. We can't just add on an extra 3". But we could assume the ratio of 12" to 14" for the single projectile will hold for the same bullet at the same speed in a two-projectile load.

The math would be this: P = 17 * 12 / 14 = 14.6

So, for this bullet at this velocity, a two-projectile load that penetrates to 17" in CB gel would likely penetrate to about 14.5" had the test been made in validated 10% ordnance gel.

Another approach might be to load up a box of "calibration" rounds of single projectiles loaded to successively higher known velocities. The known velocities translate through the models to known penetration distances in validated 10% ordnance gel. Then if I really want to know how 17" penetration in CB gel translates into validated 10% ordnance gel, I just find which of the calibration rounds penetrates to 17" in the CB gel.

[Rattlesnake Charlie]

Blue Press just ran an article on multiple projectiles in a single case. See attached.
Attachment 254361

[pettypace]

Blue Press just ran an article on multiple projectiles in a single case. See attached.
Attachment 254361

Thanks for the link. I had heard about the article, but hadn't seen it.

Must be something in the water!

[pettypace]

Bad weather, a bad cold, and Wednesday holidays have kept me from Snubbyfest for over a month. But yesterday's Snubbyfest was worth the wait. Here's why:

From the very first post in this thread, I have been referring to penetration results measured in Clear Ballistic gel. I assumed all along that bullet penetration in Clear Ballistic gel could be directly compared with the FBI 12-18" penetration requirement. Recently, the Schwartz joined this thread and carefully explained the technical reasons why my assumption was wrong.

Prompted by that warning, I went to yesterday's Snubbyfest prepared to test an idea for calibrating Clear Ballistic gel to validated 10% ordnance gel. Let me say up front the calibration method described below is only intended for non-expanding and non-tumbling projectiles.

Yesterday's testing focused on the 110 grain .36 caliber wadcutter bullet. Previous testing had shown that two of these loaded base-to-base to 600 ft/s would penetrate about 15" in C-B gel. But the "Expedient Equation" -- one of the mathematical models from Quantitative Ammunition Selection -- indicated that the same bullet, fired singly into 10% ordnance gel would penetrate to about 12.4". Based on my (mistaken) assumption, I thought the extra 3" of penetration was evidence of some sort of "drafting" effect -- maybe it was just easier for two projectiles to traverse the gel simultaneously than separately.

So, I loaded a bunch of "calibration rounds" with 110 grain wadcutter, loaded singly, with an average velocity of about 812 ft/s. According to the magic equation, these calibration rounds should penetrate about 15.2" in 10% gel. But a few fired into my C-B gel yesterday penetrated to an average of 18.75". The extra 3" of penetration seen here could not possibly be explained by "drafting" because the calibration rounds are single projectile loads. So, the extra penetration just shows the difference between the two gels that the Schwartz had warned about.

The next step is to calculate a "conversion factor" to convert measured results in C-B gel to predicted results in 10% gel. That's easy. It's just 15.2 / 18.75 = 0.81. So, if you simply multiply a measured penetration in C-B gel by 0.81, you'll get the predicted penetration in 10% gel.

Next, I fired four rounds of the duplex, two-wadcutter load into the same block of gel. The average penetration of the eight recovered projectiles was 15.25". Multiplying by the 0.81 conversion factor: 15.25 * 0.81 = 12.35"

To me, this is really good news for two reasons. First, it demonstrates a simple way to calibrate C-B gel penetration measurements to 10% ordnance gel (again, only for non-expanding, non-tumbling projectiles). And second, it shows that the mathematical models can probably give pretty good predictions for duplex loads without worrying about some bogus "drafting" confusing the results.

Finally, I tried using that same 0.81 conversion factor with some .44 Bulldog duplex rounds fired into C-B gel yesterday. Here are the results:

Average penetration of eight projectiles (4 rounds) fired: (18+16.75+15.25+15+13.25+14.25+15.25+14)/8 ==> 15.2"

Average calibrated penetration: 15.2 * 0.81 ==> 12.3"

Predicted penetration from mTHOR model: ==> 12.1"

This seems to indicate that the calibration technique outlined above is probably not overly sensitive to the diameter of the calibration rounds.

[Michael J. Spangler]

pettypace, this is a little off topic for a 2 projectile thread but I just picked up a Lyman 358627 if you want to try out something on the other end of the spectrum. I'm guessing this thing with a light charge of bullseye in a 38 snubby would tumble like mad.
Let me know if you want to try some and I'll send them your way.

[Oyeboten]

pettypace, this is a little off topic for a 2 projectile thread but I just picked up a Lyman 358627 if you want to try out something on the other end of the spectrum. I'm guessing this thing with a light charge of bullseye in a 38 snubby would tumble like mad.
Let me know if you want to try some and I'll send them your way.

What does this Boolit look like?

[Michael J. Spangler]

Attachment 256546

[a danl]

I've been experimenting recently with two-projectile loads in a snubby for self-defense. I'm wondering who else has given this serious thought.

Here are some combinations I've tried:

Attachment 238451

(1) Lee 356-95 RF base-to-base with 105 grain H&G #50 = 200 grains
(2) Lyman 356402 base-to-base with NOE 70 grain WC = 195 grains
(3) Two Lee 356-95 RF base-to-base = 190 grains
(4) Two Lyman 356404 base-to-base = 190 grains
(5) Lee 356-95 RF base-to-base with NOE 70 grain WC = 165 grains
(6) Two NOE 70 grain WC base-to-base = 140 grains
(7) One 000 buckshot over NOE 70 grain WC = 140 grains

I've been using 2400 powder for the 190 - 200 grain loads with velocities about 750 ft/s with easy extraction and no serious flattening of primers. I've flirted with 4756 for the 140 grain loads with velocities approaching 1000 ft/s but I don't like it. I won't list any specific loads and caution anyone first trying something like this that the bullets are probably going to be seated deeper than a single bullet of the same weight, so even published loads might give excessive pressure.

With everything I've tried, accuracy at 7 to 10 yards has proven more than adequate for the purpose. So my bigger concern has been penetration. Early on, i was relying on Hatcher's energy-based formula for penetration through 7/8" pine boards. That's what (mis)led me to the 140 grain combinations at high velocities and I won't admit how much time I wasted trying to determine a useful R (for resistance) value for ballistic gel. Then I finally broke down and bought the kindle version of MacPherson's Bullet Penetration book. From MacPherson I learned (what I should have already known) that penetration depends more on sectional density than energy.

Both MacPherson's graphs and the "expedient equation" from Schwartz's Quantitative Ammunition Selection show that the 190 to 200 grain combinations at, say, 750 ft/s, should exceed the 12" FBI minimum penetration standards in bare gel. So far, my actual penetration testing has been limited to a few shots into some homemade (uncalibrated) gelatin and a couple shots into a fresh brick of Clear Ballistic gel. With the homemade gelatin, three shots of the #3 combination -- two Lee 356-95 RF bullets loaded back-to-back at about 750 ft/s -- coasted through a 14" brick of uncalibrated gel proving absolutely nothing.

To date, I've only fired two shots (#1 combination -- Lee 356-95 over 105 grain H&G #50 WC at about 750 ft/s) into a 16" brick of calibrated Clear Ballistic gel. The results were at least thought-provoking. Both MacPherson and Schwartz predict the front bullets should penetrate over 16" and the back WCs about 13-14". Surprisingly, all four bullets penetrated the full 16". More testing awaits the construction of a mould to re-melt the gel.

Now, I suppose the obvious question is "Why bother?" One answer is that I accept the "Shot placement is King and penetration is Queen" mantra. But to that I would add "Lady Luck is the Court Jester." Given good shot placement and adequate penetration, whether any given bullet hits a vital target and immediately ends the threat is very much a matter of luck. And if I'm shooting at the Fitz Luck Target, I figure I have a much better chance of a winning score with two shots rather than one.

But another answer to "Why bother?" has to do with what I call the "Hamburger Factor." There seems to be some consensus that the mass of tissue crushed in the permanent cavity is a reasonable measure of wound trauma. Given full penetration of a non-expanding and non-tumbling bullet, MacPherson sets this wound mass for a .38 at 24 grams for a wadcutter and 16 grams for any other bullet nose shape. The corresponding numbers for a .45 would be 39 grams and 26 grams.

So, if both bullets from combination #1 really will reliably penetrate more that 16" of ballistic gel. That would indicate a wound mass of about 40 grams per shot and put a cylinder full from a 2" snubby on a par with a magazine full of GI hardball from a 1911.

Now, I understand that there's a lot of hand-waving involved in this with graphs and equations and theories. But 200 grains of lead at 750 ft/s is nothing to scoff at and two .36 caliber holes are bigger than one .45 caliber hole and two shots at the Fitz Luck Target will usually out-score one shot. So, if I can convince myself that the back wadcutter will reliably penetrate 16" of gel, I think I'll become a believer.

i have loaded 2 round balls into my lyman lube sizer and pushed lube between the balls and you must be careful handling them while loading as a single projectile because it's only the sticky lube holding them together at that point, 38 special at about 15 ft a figure 8 hole pattern.

[pettypace]

pettypace, this is a little off topic for a 2 projectile thread but I just picked up a Lyman 358627 if you want to try out something on the other end of the spectrum. I'm guessing this thing with a light charge of bullseye in a 38 snubby would tumble like mad.
Let me know if you want to try some and I'll send them your way.

Sorry, Mike. I've been asleep at the switch. PM coming your way.