# Ballistic Gelatin Tests

**URL:** <https://boards.straightdope.com/t/ballistic-gelatin-tests/405306>\
**Category:** Factual Questions\
**Created:** [May 24, 2007, 2:18am UTC](https://boards.straightdope.com/t/ballistic-gelatin-tests/405306 "2007-05-24T02:18:46Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![The\_Long\_Road](https://avatars.discourse-cdn.com/v4/letter/t/b5a626/32.png) [@The\_Long\_Road](https://boards.straightdope.com/u/The_Long_Road)\
**Post date:** [May 24, 2007, 2:18am UTC](https://boards.straightdope.com/t/ballistic-gelatin-tests/405306/1 "2007-05-24T02:18:46Z")

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I was looking at some data for Gelatin [tests](http://www.firearmstactical.com/ammo_data/40s&w.htm) comparing different types of 40 S&W loads. What mystified me was that some of the same rounds penetrated much deeper into clothed gelatin than bare gelatin even when the expansion in clothed was the same or more. I can understand when a round expands less and penetrates deeper, but what the heck, more expansion and penetrates deeper after going through clothing?!  
Example

.40 S&W 180 grain CCI/Speer Gold Dot JHP, 2/10/97:

Bare Gelatin  
Penetration Expansion  
14.50" 0.59"

Clothed Gelatin  
Penetration Expansion  
17.55" 0.60"

What exactly am I missing here?

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**Author:** ![Valgard](https://avatars.discourse-cdn.com/v4/letter/v/7feea3/32.png) [@Valgard](https://boards.straightdope.com/u/Valgard)\
**Post date:** [May 24, 2007, 2:56am UTC](https://boards.straightdope.com/t/ballistic-gelatin-tests/405306/2 "2007-05-24T02:56:11Z")

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The difference in expansion doesn’t seem like much (0.01" if I’m reading that right) however could the increased penetration be due to the hollow point getting a little wad of cloth jammed into it, something that won’t happen in the bare gel?

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**Author:** ![The\_Long\_Road](https://avatars.discourse-cdn.com/v4/letter/t/b5a626/32.png) [@The\_Long\_Road](https://boards.straightdope.com/u/The_Long_Road)\
**Post date:** [May 24, 2007, 3:07am UTC](https://boards.straightdope.com/t/ballistic-gelatin-tests/405306/3 "2007-05-24T03:07:20Z")

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[QUOTE=Valgard]  
The difference in expansion doesn’t seem like much (0.01" if I’m reading that right) however could the increased penetration be due to the hollow point getting a little wad of cloth jammed into it, something that won’t happen in the bare gel?  
[/QUOTE]

I’m wondering about that. In most cases I’ve read where clothing effects hollow points, the clothing acts as a [plug](http://www.firearmstactical.com/tacticalbriefs/volume4/number2/article421.htm) and keeps the hollow point from expanding.

> [@](#):
>
> For example, heavy clothing and several layers of medium or light clothing can clog the cavity of a hollow-point bullet, hindering or preventing bullet expansion, and affect tissue disruption. Careful examination of the offender’s clothing can reveal whether or not the bullet(s) passed through multiple layers of fabric, such as through the seam of a shirt pocket flap, a rolled-up shirtsleeve, multiple layers of clothing and/or other soft barrier materials

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**Author:** ![Sattua](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sattua/32/11906_2.png) [@Sattua](https://boards.straightdope.com/u/Sattua)\
**Post date:** [May 24, 2007, 5:05am UTC](https://boards.straightdope.com/t/ballistic-gelatin-tests/405306/4 "2007-05-24T05:05:13Z")

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My WAG, based on Mythbusters slo-mo shots of ballistics gel being shot, is that bare ballistics gel is capable of an incredible amount of jiggling and distortion when it is hit, which would dissipate a lot of energy. If the gel is covered with cloth, that cloth–even stretchy cotton knit–is going to prevent a great deal of the distortion, thus preventing a lot of energy absorption upon impact.