I've searched high and low, and now I’m searching some where in the middle. I’ve asked friends, supervisor, coworkers, dad, family and everyone I run into is either A) ignorant about the subject or B) just like everyone else and just don’t know. So now I ask you all, what is the significance of the SW in .40SW or the ACP in 45ACP (and if there are others that fall into this category also) I have come to the conclusion that SW is Smith & Wesson. But I’m not sure as to why they would put that on every (seems like every) .40 cal pistol. I'm in need of some serious learning here. Thanks in advanced for the replies.