Originally Posted by unit1069
Well Bullet Test Tube may or may not be equivalent to calibrated gel; I'll let the experts decide that. The company themselves says it's not equivalent, hence a conversion factor. At any rate it is a neutral medium regardless of the caliber tested as well as being a uniform consistency.
So from the article I linked, why did the 125-grain .357sig Gold Dot JHP displace twice the material as the 230-grain .45ACP JHP? Because the material is of the consistancy that it is. It's like shooting a .22 at some mud. It's going to make a larger hole than a .45 because it's moving faster.And if you know the conversion factor what's the equivalent displacement and penetration numbers for both calibers in calibrated gel? There is no equivalent for displacement. It's like shooting a lump of clay, more velocity=more permenant cavity in this kind of medium. The penetration conversion should be on the website, and is certainly included with the product. I don't remember what it was.
What I think is interesting is a medium whereby the "snapshot" of total wound volume can be approximately measured. In many test mediums the elasticity of the material makes it difficult or impossible to measure. TC is not total wound volume. The bullet test-tube gives a false-sense of permanent wound volume BECAUSE it is not elastic. Leaving aside the problem(s) of trying to closely duplicate the human anatomy Bullet Test Tube seems to me to be one simple way to make a limited but valid comparison between caliber/bullet wound displacement volumes. Only if you care about TC, and even then we know that a .45's TC is roughly equivalent to the 357SIG's from numerous photos of dyed gel we can easily google. Ergo, the "bullet test tube" is good for...nothing other than calculating penetration depth, in my opinion. If you have some wet clay somewhere on your property it's about as informative with regards to wound-volume.
Just my .02 with some fact thrown in.
ETA: Here is what an "Expert" has to say: