I've watched it since the beginning. Personally I really like it, though I wish each episode was an hour so the guys could go more into what they are actually doing to the guns.
The AK-14 with the integral silencer was cool and, even though they don't want to say, I've got a pretty good idea how they did it.
The one I couldn't figure out was the episode where the daughter sold two rifles that look like they had barrels that were less than 12" long. I didn't think that was legal regardless of where you are, but from an above post it appears that it is.