I recently acquired a box of Hornady "Critical Defense", .40 S&W, 165 grain, FTX ammunition. I am familiar with the concept of how it works but what I am curious about is the rubber-like material in the hollowed out area of the bullet point (feels like a pencil eraser). What is its composition and does it last or will it degrade over time as rubber does. I can't seem to find much info about it on the net. Anyone know about this?

I doubt that its "rubber" like we routinely think of the material, but I could not find anything in their literature that says what the tip is composed of. I tried to find the patent information on the product line, but failed. There's a lot of reading here...

http://www.hornadyle.com/asset...pplication-Guide.pdf

This message has been edited. Last edited by: az4783054,

az4783054 - thank you! That is a lot of information. I think I'll be reading and re-reading it for a while. And I am somewhat relieved to know you couldn't find anything either and it wasn't me missing something obvious. Thanks again.

It's polymer, isn't it?

I've never seen this ammo up close and am largely speculating, but find it hard to believe that the tip would be soft rubber. That would be OK for rifle rounds in a tubular magazine that are butted up against each other bullet tip to primer, but would squash, deform or catch on contact with a pistol feed ramp. A hard polymer, perhaps like that found on their Ballistic Tip rifle bullets, makes more sense.

I would think it's more akin to plastic than to rubber. Soft plastic vs a hard rubber.
It's a little slick on the surface right ?

I have Hornady Critical Defense .380 now and poked at that tip a bit with my thumb nail.

I think it's polymer, but a formulation that is more like a hard rubber. You know those little bouncy balls we all had as kids? It's about that hard I'd say.

I believe I read on the internet that it's a polymer insert, so you know it has to be true. It's designed to create a "pressure pocket" of sorts in the tip, on impact, resulting in expansion even when shot through heavy clothing, which may tend to fill up the cavity of a normal HP round. I also know from reading on the Hornady website that the 115 Gr Critical Defense is designed for short barreled guns. I carry these in my G43X and my Walther PPS M2. I use either Gold Dots or Federal HST 124 gr +P ammo in my M11-A1.

This is good test data. However it doesn’t describe what the Flex Tip material is.

http://www.hornadyle.com/asset...pplication-Guide.pdf

American Rifleman describes the Flex Tip material.

“Critical Duty ammunition achieves these two seemingly contradictory goals through the use of what the company calls ”FlexLock” bullets. These bullets have a thick jacket over the lead core and incorporate two distinctive features that help them achieve their barrier-busting goals. The first of these is what Hornady calls the ”Flex Tip,” a red synthetic insert (stylishly embossed with an”H” logo) fitted down inside a cavity in the bullet. Upon impact, the tip is driven back into the projectile, helping to expand the bullet and maximize its energy transfer. The result is consistent expansion, even at the relatively low velocities of a handgun cartridge. The tip also helps the round avoid clogging on barrier material or clothing.”

It is a synthetic material or what we engineers refer to as an engineered plastic (there thousands of varieties).

https://www.americanrifleman.o...-critical-duty-ammo/

Probably 5 years ago I bought a large quantity of 9mm 135gr +p Critical Duty. I still have some of that ammo and have never seen any degradation of the material.

quote:

Originally posted by Pale Horse:
Probably 5 years ago I bought a large quantity of 9mm 135gr +p Critical Duty. I still have some of that ammo and have never seen any degradation of the material.

Same experience here