Terminal Performance Reliability

[J-cat]

From what I understand defensive ammunition is designed to perform inside certain parameters, i.e. expand and penetrate between 12-18" through a variety of barriers.

But how reliable is ammunition? I read a bunch of material and saw all the internet videos of the gel tests showing amazing feats of expansion and penetration. But I also read this:

http://www.firearmstactical.com/pdf/fbi_10mm_notes.pdf

and what I took away was that 9mm and the 38 were unreliable, meaning they passed the FBI shooting protocol only 59% of the time. From what I see, the toughest test to pass is the windshield test.

So here is my question:

Since today's ammo is so much better than 20 year old ammo, hue much more reliable is it through windshields?

When testing through windshields, how many rounds are typically fired? Where can one get their hands on that data?

Another question I have is in regards to ballistic gelatin:

I understand bullet penetration in ballistic gelatin to represent the average penetration in human tissue. So, a round that penetrates 13" in gelatin may penetrate 10 to 16" in a human being.

Would it not be better to select a round that penetrates 16" in gelatin? That way it would be more likely to penetrate FBI's minimum of 12" in all cases and thereby increasing it's reliability?

[MegademiC]

Have you read all the tacked threads? I also suggest reading a couple pages deep at least in this subforum.

The recommended loads from Doc (contained in a tacked thread), have all been vetted. I dont know the exact percentages but they are all reliable enough that people who know their stuff have no reservations using any of them. For my purposes, when I see that, I feel confident - especially since they openly back up the choices with solid scientific data.

As for the question about a 16" penetrating round. If its a standard expanding round, and it is shot through sheet metal, there is a chance(some better than other depending on round) that the petals will shear off leading to increased penetration - overpenetration.

12" minimum is for worst case and all of doc's recommended loads reach this(or get very close) very consistently, even after passing through various barriers.

One last thing to keep in mind is that these loads are designed to "do it all." They have to be able to expand well in bare gel, yet not break up going through steel or autoglass, and not get clogged by wood or wallboard. This is a very tough thing to do from an engineering standpoint, but the latest generation of loads do these well.

If you look up FBI wound ballistics protocol, you may be able to find the numbers you are looking for.

Also, you may find this interesting : http://le.atk.com/general/irl/woundballistics.aspx

I am not an expert, but have been trying to keep up here best I reasonably can - just sharing info I've come across.

[J-cat]

I reviewed ATK's Wound Ballistic Workshops as well as their HST bullet chart and observed that the 147gr HST failed to penetrate a minimum of 12" through auto glass 8 out of 9 times. The range of penetration was 7 to 14", but mostly closer to 7". ATK's claim of 11" seems to be overly optimistic.

Winchester claims 12" for their bonded 147gr load. Since RA9T is a solid 10" auto glass penetrator, I believe Winchester's claim more than ATK.

[sobiloff]

Since today's ammo is so much better than 20 year old ammo, hue much more reliable is it through windshields?

Bonded bullets didn't exist 20 years ago, and that's the major advancement. Bonding increases consistency (key word being "increases"). No bullet is always going to perform exactly like it tests every time, be it from small variances in any part of the cartridge or firearm, or in the intermediate or terminal media. But, on the whole, today's bullets are much more reliable than those from 20 years ago.

Pick your favorite from DocGKR's list, make sure it functions reliably in your firearm(s), and spend your time practicing, not worrying about inconsequential increments.

[J-cat]

I thought this forum was for worrying about inconsequential increments.

See, I have theory as to why these bullets fail through auto glass:

They're too soft. They're like a Honda Civic trying to punch through s brick wall. They are designed to expand, just as the Honda is designed to crunch. I think this aspect causes the bullet to transfer it's energy to the glass over a broad area. Much of the bullet energy is wasted punching through the glass and there's not enough left to allow the bullet to penetrate deep enough through the gel.

One way to improve this performance is to add mass. That's why the .40 does better. But there's gotta be a way to improve the 9mm. I noticed the 124 Gold Dot does pretty well. It's got a bonded jacket. But more importantly, it's lead core is much harder than the rest. I discovered this when trying to mushroom one with a hammer. This bullet is very hard and you notice it through feedback as you're pounding on it. I think this aspect allows the 124 Gold Dot to hold together while passing through glass.

What would be nice is if ATK used antimonial lead in the 147 HST and drove it to 1200 FPS. I really like the bullet: it has the slits in the jacket for reliable expansion. It has that heavy cannelure to lock in the core without going to bonding. It is really really accurate in accurized pistols, but it could have been so much better. I betcha the Underwood 147 Gold Dot will punch through windshields and penetrate deep enough all the time.

Maybe the standard 9mm is too weak.

[jdallen]

If I'm not mistaken, this is why the Doc recommends .40 for duty use around vehicles IF a reliable platform is available ( because reliability trumps everything).

I'm a citizen, not a LEO and don't foresee too many situations in which I would be shooting at people through windshields. So I carry 9mm for the higher capacity and better "shootability".

Different tools for different needs, man.

[J-cat]

As a private citizen, you may find yourself having to shoot through a dual or triple pane sliding glass door to stop a threat. Bullet through glass performance is important.

I'm wondering, though, if the gel blocks in all these ballistic workshops were consistent. My understanding is the prep work hast to be meticulous and depending on who prepared the gel, that could explain the wildly erratic results. One agency gets 7" of penetration through glass while another sees 14" with the same load. How can there be a disparity of nearly 100% in penetration? Same bullet. Same glass. Same gel.

[sobiloff]

I'm wondering, though, if the gel blocks in all these ballistic workshops were consistent. My understanding is the prep work hast to be meticulous and depending on who prepared the gel, that could explain the wildly erratic results. One agency gets 7" of penetration through glass while another sees 14" with the same load. How can there be a disparity of nearly 100% in penetration? Same bullet. Same glass. Same gel.

Ballistic gel is calibrated with a BB to ensure correct/consistent density. (I can't remember the required stats on the BB and depth, but there is a standard.) A good test will calibrate the gel prior to performing the test.

Also, glass ain't all the same. How thick is it? Is it glazed? Is it tempered? Same for automotive windshields; modern ones are much thinner and lighter. Did they get the angle of the windshield the same between tests? Without knowing which tests you're referring to, and the exact kinds of glass they used (along with the setup), it's hard to comment.

[vicious_cb]

Not to mention those ballistic workshop charts are a joke. From Molon:

"I’m going to assume that you are referring to the ATK Wound Ballistic Workshop at Fort Collins on 6-26-08. Please correct me if my assumption is false. That Workshop has a major credibility issue regarding the 64 grain Gold Dot data. As you stated, the test weapon was a 16” barreled RRA LAR-15. The Workshop reported a velocity of 2575 fps for the 64 grain Gold Dot fired from said 16” barrel.

Now, look at the data from the ATK Wound Ballistic Workshop at Aurora on 6-24-08. This Workshop reports the velocity of the 64 grain Gold Dot as exactly 2575 fps, when fired from a (Colt) Commando with an 11” barrel. It would be next to impossible for two different barrels with a difference in length of 5” to produce the exact same velocity with the 64 grain Gold Dot. It's obvious that the velocity data for the 64 grain Gold Dot from one or both of the Workshops is false.

Since the Workshops failed to accurately determine/record something as basic as the velocity for the 64 grain Gold Dot, I question the validity of any of the Workshops' reported data for the 64 Grain Dot; especially something as crucial as the penetration depth. We know that DocGKR strictly adheres to the established protocols for terminal ballistic testing and I consider his penetration results for the 64 grain Gold Dot to be the current standard for this load."

[J-cat]

Ballistic gel is calibrated with a BB to ensure correct/consistent density. (I can't remember the required stats on the BB and depth, but there is a standard.) A good test will calibrate the gel prior to performing the test.

Also, glass ain't all the same. How thick is it? Is it glazed? Is it tempered? Same for automotive windshields; modern ones are much thinner and lighter. Did they get the angle of the windshield the same between tests? Without knowing which tests you're referring to, and the exact kinds of glass they used (along with the setup), it's hard to comment.

I was referring to the ATK ballistic workshops. They didn't go into enough detail, but I was assuming they were doing things correctly. At least it appeared that way in the photos.