Originally Posted by diginit
PPT = person to person transfer
ACP = automatic centerfire pistol
PPT is generally short for Private Party Transfer, but I guess that Person to Person works as well.
ACP is not "centerfire", it stands for Automatic "Colt" Pistol or Automatic "Cartridge" Pistol. There seems to be some dispute on this, but in common usage, "Colt" trumps them all.
All of the "ACP" round first appeared in Colt (Browning design) guns.
What's scary is that this could start an ammunition acronym list....
and that's just a few off the top of my head...