I was about to ask where you found this info, then realized; it must be on the internet somewhere.
So I went looking and found this forum thread concerning the .380acp round. A wealth of info here... and I did find the Winchester info
Manco refered to.
http://www.ktog.org/cgi-bin/yabb2/YaBB.pl?num=1199737660
Sorry, I wrote that message real quick and neglected to include the source. Terminal ballistics test results for some of Winchester's LE/personal defense ammo can be found here:
http://www.winchester.com/SiteCollectionDocuments/flash-SWFs/law_bullit.swf
Be careful when choosing which results to trust, by the way. I use the Brass Fetcher site a lot because the gelatin is prepared properly and I can verify that the penetration of the calibration BB meets industry standards. I also use FBI data whenever that's available.
Someone want to explain to me what the "cutting perimeter is" as described in the brassfetcher tests? Why not just measure exapansion, like everyone else does?
Judging by the pictures, it appears to be the outside perimeter of the expanded (or unexpanded as the case may be) bullet, which is approximated as the diameter * pi (about 3.1415926535897932384626433832795). As to why this was done, I have no idea.
I chronoed the Corbon DPX, Hornady CD, Winchester PDX1, and Winchester FMJ one afternoon. To my surprise Unless my chrono was malfunctioning the DPX was the slowest of all four bullets I tested. The PDX1 averaged 5 fps faster than the CD and the FMJ bullets were right behind the CD's
Well, DPX uses an all-copper bullet, which is less dense in terms of mass and therefore longer than it would be with a lead core, which reduces the amount of space left over for powder (not that the powder is necessarily packed, but a smaller volume still imposes limitations regarding pressure, which results in less velocity than you could normally get).
I have seen more and more posts about PDX1's not always expanding so my main carry load in every Caliber is the Critical Defense.
Like any traditional hollow-point bullet, PDX1 can sometimes get clogged with various materials it encounters, including clothing, which can make it expand only partially or not at all. There are ways to work around this, but they all involve tradeoffs. For example, you could use a plastic insert like Critical Defense does, but then the bullet will always expand no matter what it hits, which means that hard barrier penetration will be relatively poor. You could widen the cavity instead, but this could compromise feeding reliability.
PDX1 is designed to expand as reliably as possible while still being able to achieve lethal depths of penetration after penetrating hard barriers. If that's not important to you (it certainly isn't to everybody), and you'd rather have virtually guaranteed expansion, then Critical Defense or HST or some others may be a better fit for you in this caliber. For me it always comes down to the individual load for the individual gun, and of course the preferences of the individual person. I happen to use PDX1 in my M&P40, but in a .380 ACP pocket pistol, I'd use a hard-cast bullet and forget about JHPs altogether. To each their own.