I read the thread and agree that your reaction seems out of proportion to the problems you cite, and that you are short on putting yourself in the other guy's shoes.
The printer story sounds believable though you wound think they would have just reprinted the whole batch of orders. Probably they didn't realize that it was more than one order that got fouled up, or somebody didn't investigate thoroughly enough at the time.
I don't like hearing one story before the order, then another one while waiting for delivery, either. You had every right to get P.O.'d, but is it really very likely that the problem with quoting the incorrect delivery time actually has some impact on the reliability of their pistols?
Their reputation for quality is pretty damn good as far as I know, so I don't think the "how can I trust my life to you" argument really does anything for you. Enough to say that you'e mighty P.O.'d at the way they screwed up on you, and leave it at that.
They did you wrong twice and seemed to be willing to make some concessions to you, but you have pretty well slammed the door on them, and leave them without any way to make it right.
Next time hang in there a bit more with the vendor and give them a little more slack, you'll probably be happier with the outcome.