9mm carry ammo...115 or 147

[C0untZer0]

I just saw that Mr. Ammo Quest put out another video on Hornady 147gr Custom 9mm, just bare gel:

http://www.youtube.com/watch?v=QGUw2pX5IK0

He yaks too much and ends up contradicting himself. Is it just his opinion that 18" is too much penetration? I'm wondering where that 18" number comes from?

It's a minor point but I think he has a misunderstanding of the IWBA four-layer heavy denim protocol.

He says of the IWBA test protocol that it

represents an absolute worst case scenario for clothing, plugging of the hollow point cavity and interfering with the bullet's expansion

He's a little dramatic at times and "absolute" is an over-used word IMO. Anyway the four-layer heavy denim test is not the absolute worst case scenario for clothing and was never meant to be. Duncan MacPherson said himself that the four-layer heavy denim test does not represent a simulation of any specific clothing.

The FBI heavy clothing test might have been a decent test for ammo selection (and maybe not) It definitely was not a good means to use for ammunition development and design.

My understanding of the IWBA four-layer heavy denim protocol is that it allowed for more consistent evaluation of bullet behavior - specifically bullet performance through soft barriers. From a design perspective, testing through "heavy clothing" was rather arbitrary, and MacPherson set out to find what specifically about clothing affected bullet behavior.

 

[eldon519]

I just wikipedia'ed the topic and the 18" is an FBI number. Fackler apparently suggests 12.5"-14". The article mentions that the actual penetration requirement isn't so much because that is how much penetration is needed or desired, it is to ensure the bullet is still moving fast enough through the actual required depths to create a wider crush cavity. Apparently as the bullet slows to a stop, the tissue destroyed diminishes. So basically there is already a margin of extra penetration built in. The article also noted that the backside skin can trap a bullet going 250fps 50% of the time which helps to mitigate overpenetration.

It is just a wikipedia article though.

 

[C0untZer0]

I'm thinking they're getting this from the Handgun Wounding Factors and Effectiveness report where on page 11 it says:

It is essential to bear in mind that the single most critical factor remains penetration. While penetration of 18 inches is preferable, a handgun bullet MUST reliably penetrate 12 inches of soft tissue at a minimum, regardless of whether it expands or not.