Friday, December 11, 2020

Speed and Expansion

Four layers of denim is a challenging barrier for expansion, especially for slow projectiles and older hollow point designs. For a slow, older hollow point? Expansion actually becomes somewhat less than likely.

On the left, a 225gr .45 Colt Winchester Silvertip, and on the right is a 230gr .45ACP Remington Golden Saber. Both were fired out of a Blackhawk Convertible, one of the birdshead ones with a 4.6" tube.

The Silvertip peeled a petal back but the Golden Saber didn't deform noticeably at all. Both exited the block on the far side and were stopped by the cloth on the backside. Penetration was adequate without being excessive, but they didn't do anything a LRN projectile wouldn't have done.

A Silvertip from the same lot was fired into the block from a 16" lever-action carbine and performed rather differently...

Out of the levergun, the round had enough steam to expand violently, but still enough momentum to traverse the entire length of the block, coming to rest slightly protruding from the far side. Nearly ideal performance for a pistol bullet, it just needed to be launched from a long gun to attain it.

Incidentally, we also fired a .45 Colt Hornady Critical Defense load, using the 185gr FTX flex-tip projectile. It also expanded violently but, being on the light-for-caliber side of things, stalled out after around 12" of penetration.

This is marginal performance at best. On the upside, if fired out of a CCW revolver with a 4" or shorter barrel, it likely wouldn't have expanded at all and would have therefore penetrated just fine. Or you could have used a cheaper semiwadcutter.

Footnote from a discussion on the Bookface: 
"It's my experience that, as velocities go up, Clear Gel results get wonkier due to the difference in the shear characteristics of the two mediums, to the point that at rifle or near-rifle velocities there's no meaningful correlation to be even guessed at. I also try and avoid reading any tea leaves in Clear Gel from where or how quickly the projectile upsets. 

It's easy to draw unnecessary conclusions from the fact that duty handgun rounds that perform well in 10% ordnance gel also tend to perform well in Clear Gel."