dwinsor... no excuse for the trigger disappearing, I agree. Intentional or Accidental.
However, after reading through all your info provided, I have to agree that possibly
1) you just got a lemon which unfortunately happens with ANYTHING we buy or
2) that the ultimate cause of your problem with the barrel had to do with the bp not being fully and properly seated from the get go, thus creating the whole issue.
Either way, I can understand why you are upset. However, I have owned over a dozen Knights (many are bolt action like yours) and never had a quality issue at all. They have all been outstanding rifles both in quality and performance. I can't speak to how they handle their warranty, as I've never needed it.
Another thing I'm not sure I saw in reading.... did you teflon tape or grease your breechplug? If not, you can get blowback through the threads even if everything is perfect, which is sounds like yours wasn't (by default or damage) which would make it even worse.
Good luck in your endeavors.