Buffalo Bore shows they've tested their 380 ammo I'm using in the following guns:
1. BDA-3.75 inch barrel----1218 fps
2. Walther PPK-3.5 inch barrel-----1200 fps
3. Colt Mustang Pocket Lite-2.75 inch barrel---1123 fps
4. Keltec---1100 fps
They've chronographed all their loads in their personally owned Kel-tec's and the others listed, and though I wouldn't recommend using it on a regular basis, I'm sure Buffalo Bore didn't have a problem with the guns in their testing to list those guns specifically on the site.
Shoot 2-3 mags to make sure it works in your gun, clean it and reload it with the same rounds. Practice with standard velocity ammo and save the good stuff for the BG's
The critical defense 380 lists the same bullet weight at 100fps slower than the BB load. Thats just 10% less velocity and I'm quite sure the Kel-tecs are well within safety standards and are capable of handling the 10% over standard velocity ammo.
The double tap will act almost like ball ammo with very little expansion, not worth the effort to use it as a HP when there are loads out there that dig deep and expand reliably at the same time.
BB's 100 grain lead bullet will do the same thing as the double tap and expand at least as much if it hits a bone. It doesn't suffer from potential plugging on clothing either.