32NAA cartridge in ballistic gelatin

[Brass Fetcher]

I have just finished busting some caps into gelatin with my .32NAA and would like to share the results :

Block calibrated at 9.8cm and 600 ft/sec velocity

Firearm was .32NAA test barrel with locked breech and 2.750" barrel length.

Federal 65 grain Hydra-Shok JHP ( 14.5" (corrected) penetration, impacted at 1112 ft/sec, 0.425" average diameter)

Winchester 60 grain Super-X Silvertip hollowpoint ( 8.6" (uncorrected) penetration, impacted at 1218 ft/sec, 0.408" average diameter with total core-jacket separation)

Speer 60 grain Gold Dot JHP ( 6.4" (uncorrected) penetration, impacted at 1237 ft/sec, 0.494" average diameter with total core-jacket separation)

Magtech 71 grain JHP (11.6” (corrected) penetration, impacted at 1097 ft/sec, 0.446” average diameter)

Hornady 60 grain XTP JHP (9.9” (corrected) penetration, impacted at 1168 ft/sec, 0.396” average diameter)

Hornady 71 grain XTP JHP (10.8” (corrected) penetration, impacted at 1104 ft/sec, 0.442” average diameter)

Hornady 76 grain XTP JHP (12.9” (corrected) penetration, impacted at 1040 ft/sec, 0.410” average diameter)

Hornady 85 grain XTP JHP (exited block at 10.6” (uncorrected) penetration, impacted at 988 ft/sec, 0.368” average diameter)

These were premium JHP bullets pulled from factory .32ACP cartridges and in the case of the 71 and 76 grain XTP bullets, modified by cutting material off of the base of the bullet.

- JE223

 

[RyanM]

Hm. The Hydra-Shok did surprisingly well. Out of those, I'd probably pick the 76 gr. Hornady.

 

[Sylvan-Forge]

JE223,

Thanks for posting that. Very cool!

I noticed on your site, you tested corbon's 71gr FMJ. Might you know roughly how deep it was into the wood?

 

[North Bender]

Busted caps?

 

[Brass Fetcher]

Sorry, most of my other posts regarding gelatin have been so formal, I thought I'd mix things up a little bit. Really though, this test session was more like 'clocking' the gelatin than 'busting a cap' in it.

Hmmm, the 71gr FMJ from Cor-Bon ... ... I don't remember it being deep enough in the wood stopper to need pliers to remove. This round appeared to retain its velocity deep into the gelatin - the cracking in the gelatin was pronounced up to ~ 8" depth.

JE223

 

[Sylvan-Forge]

Many thanks, JE223.

 

[Jim March]

Interesting. Looks like you CAN drive a Gold Dot too fast!

Considering the slug was probably designed for about 850fps, it's moving over 250fps over it's design speed. Huh. So...my 135gr 357 "short barrel" loads from my 4.68" tube New Vaquero will be...maybe 150fps past designed speed. OK, should be arright .

 

[Bobo]

Verrrrrrrrrrrry interesting!

The three FASTEST bullets had the LEAST penetration!

1237 fps -- 6.4"
1218 fps -- 8.6
1168 fps -- 9.9
______________
1112 fps -- 14.5
1104 fps -- 10.8
1097 fps -- 11.6
1040 fps -- 12.9
0988 fps -- 10.6

 

[Brass Fetcher]

Bobo,

I'm glad that you got some good info out of the results.

Basically, the faster a bullet moves through a liquid, the greater the decelerating force acting on the bullet. This means that lighter bullets will strike the target at a higher speed, but may be moving slower than a heavier bullet would at any given penetration depth (everything else being equal). It's a lot like a boat in water, really - the faster you go the more fuel you burn and the more the engine works to push the boat faster and faster.

I say this with no offense intended anyone, but this is the main reason why I am dumbfounded that after at least 20 years of valid research into pistol wounding characteristics, there is still a sizeable number of persons who believe that 'light and fast' pistol bullets are the answer to 'stopping power'.

Heavier and (by necessity) slower pistol bullets are more efficient at damaging tissue than are light and fast bullets. For one, heavier bullets can be given slightly more 'umph' (momentum) than lighter bullets due to their greater dwell time in the barrel and hit the target at any distance with greater momentum (due to the reduction of wind drag, with is largely dependant on the speed of an objects travel). This means that the bullet can expand to a larger expanded diameter and have greater momentum left to overcome the increased drag forces in the gelatin (due to the larger hole created), so adequate penetration depths are still met. The only difference is that you end up with a larger hole in the target with the heavier bullets.

In my 9mm luger, I have 147gr JHP, .38 Special 158gr HP, and .45ACP 230gr JHP. I like the 9mm and .38 because they are easy to carry, I own the .45 because they don't make a 0.46.

 

[RyanM]

Actually, a lighter bullet (assuming the same penetration depth and everything else) must necessarily be moving faster than a slower one at any given point in the wound track. There'd be no other way for it to overcome the forces acting on it.

 

[Brass Fetcher]

Almost forgot to post the pics of the cartridges. Enjoy!

They are, left to right :

Winchester 60gr Silvertip
Speer 60gr Gold Dot
Magtech 71gr JHP
Federal 65gr Hydra-Shok
Cor-Bon (.32ACP bullet) 60gr JHP
Hornady 60gr XTP JHP
Hornady 71gr XTP JHP (bullet base turned down on lathe from 85gr XTP)
Hornady 76gr XTP JHP (bullet base turned down on lathe from 85gr XTP)
Hornady 85gr XTP JHP

 

[st_albert]

Basically, the faster a bullet moves through a liquid, the greater the decelerating force acting on the bullet. This means that lighter bullets will strike the target at a higher speed, but may be moving slower than a heavier bullet would at any given penetration depth (everything else being equal). It's a lot like a boat in water, really - the faster you go the more fuel you burn and the more the engine works to push the boat faster and faster.

I say this with no offense intended anyone, but this is the main reason why I am dumbfounded that after at least 20 years of valid research into pistol wounding characteristics, there is still a sizeable number of persons who believe that 'light and fast' pistol bullets are the answer to 'stopping power'.

Although I'm not one of the "light and fast" proselytes, I think they would point out that the faster deceleration means a bigger pressure wave. There are those who believe that even with pistol ballistics, things like shock wave/pressure wave and generating a large temporary stretch cavity are important mechanisms for incapacitation. It's a difficult proposition to prove, however (or so it seems to me), and I'm not sure I buy it.

 

[Brass Fetcher]

Definately, I would not shut the door just yet on those sorts of theories. Aside from the medical aspect (IE how do organs react to thus and such), such questions are fluid dynamics problems. FD is an area that most engineers don't seem to like and for those that do it, the subject area is usually very challenging, especially with flow regimes like a bullet traveling through a tissue simulant, etc.

How do you like my painstakingly handloaded cartridges? Anyone? (Come on, just one pat on the back for the shiny brass and nickel cases!)

 

[RyanM]

They do look shiny. Especially compared to my reloads. I have highly acidic skin.

I'm starting to think that the pressure wave theory may have some merit, though I wish I knew some psychologists which weren't rabidly anti-gun. According to Dr. Roberts (I think it was him), 40% of law enforcement shootings result in the suspect collapsing nearly instantly, for absolutely no apparent physiological reason. I believe Fackler said it's possibly because years of exposure to TV and movies have caused a hypnotic suggestion to fall down when shot, or some other psychological mechanism.

While I buy the possibility that some shootings may result in the shootee falling over due to psychological mechanisms, 40% sounds way too high for me. An actual psychologist might be able to give a better estimate.

Given Michael Courtney's faith in the Strasbourg shooting data, once I get some free time and a copy of all the Strasbourg data, I plan on running the numbers through my terminal ballistics calculator and seeing if the incapacitation times of lower-energy loadings correlate with wound volume, and also whether there is an energy threshold at which incapacitation time is shorter than would be predicted by wound volume alone.

One problem is that most people calculate the portion of the wound made by direct contact with the bullet only. A significant amount of tearing and widening of the hole can occur, solely due to the stretching of the temporary cavity, starting at an energy level of about 400 to 1000 ft-lbs, depending on the specific bullet characteristics, especially fragmentation.

It may be that this additional trauma causes incapacitation faster than a crush-only wound model would predict, or it may be a pressure wave remotely affecting the central nervous system.

 

[st_albert]

As I said above, I'm not sure I buy the pressure wave theory. But I don't reject it out of hand either, no matter what Papa Fackler said.

Anyone who's been soundly punched in the solar plexus knows how incapacitating that can be (albiet temporarily) even in the absence of penetration or massive tissue disruption. That makes the pressure wave theory seem at least plausible to me. Of course the archetypal bad guy, hopped up on coke and PCP, may be immune to that kind of effect. I hope I never get to find out.

 

[Vitamin G]

I'm starting to think that the pressure wave theory may have some merit, though I wish I knew some psychologists which weren't rabidly anti-gun

Oh but you do!


Psychologists, Counselors, Therapists. We're all pretty much the same, no matter which one the company you work for, decides to call you.

 

[RyanM]

Okay, great then. I know who I'm going to if I ever go crazy!

But on the original topic, what would you say is a reasonable figure for percent of criminals that would collapse if you shot a blank cartridge at them? Is 40% too high?