To be specific, those that just plain don't work well as purchased. It seems that most pistols and longarms I've bought the last few years required much patience, a trip or two back to the factory and a bit of work by me to make them perform. My short list includes a Savage .308 bolt action that had extraction issues, feeding problem, a serious timing problem that made cocking very difficult, terrible accuracy. Two trips to the factory plus hard work by me on the bore finally made it work and shoot accurately. Next is the SW-99 Walther copy that wouldn't feed, magazines wouldn't lock the slide open. A new barrel from S&W and quite a bit of research by me to find that my magazines had an older defective follower design seem to have it working well. I could name two or three more but my point is that considering modern technology and manufacturing processes, why new firearms are not better is lost to me! I think part of the problem is that 100% reliance on that new technology has replaced craftmanship, we have operators instead of machinists, instead of gunsmiths working in reapair departments, we have parts changers that know less about firearms than we, the customer do.