There are many brands that have gone thru phases where there are production periods of quality guns and periods of QC lacking guns. Jimenez is one that has had a majority of the latter, until lately, especially with the JA-Nine. The way to tell the difference is in the packaging. The old style with frame cracking issues and weak takedown pins came in the old box style, with detaching lid. The new strengthened versions come in a fliptop lid type box. That's what I've determined in my experiences with JAs from both eras and confirmed by others who've also come upon the same conclusion, both buyers/users and dealers.