For me.. the Llama .380, had one actually fly apart!!!!
The Clerk 1st, pick a caliber...
RG's... all real POS's
Raven Arms...any and all of them,
Jennings 22's,
Kahr's not many are put together that well, I just think it is a crappy design..
I have had a Browning Hi-Power give me fits, learned to hate the gun, but we finally fixed the problem... tight slide, and weak extractor spring with a burr on the underside of the extractor as well as a worn or short ejector.. dang that gun gave me fits....
I'm really surprised to see several people mention the Walther PPK's Granted the DA Triggers on the Smith version are not all that great.. but overall they are pretty good guns.. a lot of gun designers have borrowed features from them, the Beretta 92,s & 96's all have safety features borrowed from the 1930's Walther design... I have several, and yup, the German made ones are of better overall fit and finish..
I am not surprised to see, the 1911 listed by some as a "Jamomatic" however experience tells me that MOST (not all) function problems with 45's and new shooters are more bad technique and habits than the gun it's self.. I am really surprised to see Kimber 45's mentioned as problematic.. they factory fit and finish on them is generally very good.. Most ALL stovepipe type jams are shooter issues riding the recoil, any semi auto.. I and my business partner own about 6 or 7 Kimbers between us... never a problem with any of them..
Generally 45 1911 function issues that are not shooter related are fixed pretty easily with either spring swaps, or a little fitting.. many times it is magazine issues, especially with aftermarket mags..