Twist rate for the 380 ACP is essentially 1 turn in 10". That means inside the human body it basically turns a single revolution assuming it passes completely through and is not impeded in any way. Therefore, the "cutting" action is nil hence compression-type terms such as "crush cavity" and "stretch cavity" are used. One of the false accusation made against the Winchester Black Talon was they "cut through the human body like a buzz saw". It wasn't true then and it's not true now.That would normally be true, but these Lehigh's penetrate (and because of the weird nose shape) cut a hole like a hollow point without expanding. Novel design.
One test: https://www.youtube.com/watch?v=LczfeWK9lHw&list=UUAWFWuY7JafjZNE_dG8BshA
My understanding of the gelatin testing is that 10% ballistic gelatin closely simulates the same type of resistance that human muscle does which gives us a pretty good idea of just how deep we can expect a bullet to penetrate the human body, but on the other side, gelatin does not simulate the stretch and permanent cavity effect very well.
Based on the Underwood/XTP gelatin test done by Shooting The Bull the underwood did not perform as well as other brands using the XTP bullet did.Are there gel shots of the Underwoods? They may penetrate 20+" now and that velocity...
The poster I was referring to was talking about an Underwood loading of the Lehigh solids that are the subject of the OP. I would expect them to over-penetrate with higher velocity since they don't expand like the XTPs.Based on the Underwood/XTP gelatin test done by Shooting The Bull the underwood did not perform as well as other brands using the XTP bullet did.
I' convinced that increasing the velocity of an XTP bullet is a negative and that this particular bullet has it's best performance in less than 900fps range.
When the XTP in 380 gets up to 1000fps it expands too much which reduces penetration.
The link to the Underwood gel test is...