Mas, Thinking about a Gen 4 G19 a bit down the line, when all the issues are shaken out. Have a Gen 3 G19 but grip has always seemed a bit off for me. The Gen 4 grip feels good in shop, so may give it a try in lieu of grip reduction on Gen 3. Discussed with JR on another thread using the Gen 3 recoil spring adaptor for standard velocity loads and Gen 4 dual spring for +P carry loads. While I would probably under this procedure have the Gen 4 standard dual spring in the glock, if used for defense, maybe not. Things happen and I would probably use the adaptor for standard velocity fed 9BP loads, which I like and may carry. So to my question after long background. Do you see any legal problems defending yourself with Gen 4 glock using Gen 3 mainspring with aftermarket adaptor? I would also sand off the ridges in grip, install aftermarket night sites, install trigger with smooth face (glock manufacturer), and maybe install NY1 trigger spring and negative connector (again use glock manufactured parts). On the last modification have to see how the Gen 4 standard trigger feels.