History of using layers of denim in balistic testing?

[JustOneGun]

I only know enough to be dangerous when it comes to ballistic testing criteria and how it changes bullet design for good or bad. Knowingly, I am asking for a very simplified answer in a complex field.

While working in aviation I came to understand the government selects many materials in order to standardize tests for repeatability and availability of said material. Manufacturers then tailor their product to maximize the test. This may or may not maximize performance given the above tradeoffs of standardization when compared to the real world.

With this in mind I have two questions:

1. Is there real world morgue and ER results that settle the test on a certain number layers of denim? How scientific was it?

2. All things being equal and given the design of the tests, do scientists expect to see a variety of expansion and penetration depths between the minimum and maximum dependent upon how much the individual bullet clogs? If not expecting a proportional result, what are they expecting?

[Chuck Haggard]

http://www.firearmstactical.com/tact...2/0604-02a.htm

http://www.ar15.com/ammo/project/Fac...hester_9mm.pdf

In the FWIW department, almost every 124gr +P Gold Dot that I have seen that has struck a bad guy in one of our OISs looks exactly like those recovered from the 4LD gel testing.

[JustOneGun]

Chuck,

Thanks for the links. I have read the article quoting MacPherson but every article I find is lacking the last three pages where it discusses how the 4 layers was determined. It seems to be MIA. (: Is it in one of his books and if so which one?

What I did read in the article made me even more curious. MacPherson states that in CHP's shootings a very small percentage of the bullets failed to expand. Was he basing his conclusions off a small percentage of failures in one brand of bullet?

Through my ignorance of ballistic testing I'm sure there is something obvious I'm overlooking.

[Chuck Haggard]

The 4LD test was used as a worst case scenario test, since "heavy clothing" meant a lot of different things to different people, and the denim would be easy for everybody to duplicate. Every bullet that I have seen that does well on the 4LD test has done well on the street.

Previous to us using the Gold Dot we used the Hydrashock, and saw more than a small sample of bullets that failed to expand through clothing in our OISs.

[DocGKR]

MacPherson D: "Improved Handgun Ammunition". Wound Ballistic Review, 3(3):12-21, 1998.

[JustOneGun]

Chuck thanks for the input, I was wondering if there was a problem prior to the test and a subsequent reduction of that problem. I do understand the need for standardization of tests and was not questioning the need for it. I don't believe that I will get an answer as to how 4 layers was determined to be better than 2, 3 or 5?

My initial question came about because if the 4 layers was picked as an extreme test that is actually overkill, then in trying to pass that test are manufactures having to do something to a bullet design that perhaps makes it not expand as large as possible given a more realistic test criteria?

So having a test that is a more than what is seen in reality is a good idea. Having a test that is way overboard might actually hinder performance. I am not suggesting that is what is going on. I don't have enough expertise and experience when it comes to ballistics. I was just curious as to the history of the tests development and how it changed bullet expansion, cost, higher speed impeding recoil recovery, etc.

[Sigfan26]

The Canadian tuxedo was more popular in the early 90's than today. While many consider 4ld to be overkill, if something kicks ass in that, it's gonna rock in almost any environment.

[JustOneGun]

Thanks Doc, I read that one but have been unable to find a copy that actually has the history of development. The closest I got was, they experimented and determined 4 layers was best.

So they experimented with different materials and found denim clogged the best. Then they experimented with different brand rounds or just one round that passed fbi tests but had shown to fail in the human body? Then with these bullets they kept adding layers until they replicated the failures seen in the body or a slightly higher percentage or did they keep adding layers until they all failed? The difference could be important.

I was just pondering the history of the test.

[JustOneGun]

The Canadian tuxedo was more popular in the early 90's than today. While many consider 4ld to be overkill, if something kicks ass in that, it's gonna rock in almost any environment.

That may or may not be true.

Back in the '80's the Navy E-2 aircraft had an ashtray that cost hundreds of dollars (I think it was either $400 or $800 one was the army's hammer) It kicked ass on a lot of difficult and elaborate tests that the Navy required. There were two important things concerning that ashtray. 1. It was just like the one I made my dad in high school sheet metal shop. It cost me like $10 and 45 minutes to make. 2. When the planes got to the squadrons we took the ashtrays out and put them in a closet. Smoking in a plane full of electronics is not the best idea. Go figure.

So we wasted a lot of money and time for a product we didn't want and with tests that were overkill. That overkill drove up the cost.

[Sigfan26]

That may or may not be true.

Back in the '80's the Navy E-2 aircraft had an ashtray that cost hundreds of dollars (I think it was either $400 or $800 one was the army's hammer) It kicked ass on a lot of difficult and elaborate tests that the Navy required. There were two important things concerning that ashtray. 1. It was just like the one I made my dad in high school sheet metal shop. It cost me like $10 and 45 minutes to make. 2. When the planes got to the squadrons we took the ashtrays out and put them in a closet. Smoking in a plane full of electronics is not the best idea. Go figure.

So we wasted a lot of money and time for a product we didn't want and with tests that were overkill. That overkill drove up the cost.

Comparing bullets and ashtrays is like comparing Apples and hamsters... Who doesn't want a better performing bullet?