After hearing about doing this, I went on an ordered 100 4x40 set screws (Grainger, Inc.), couple Allen wrenches and a tap. Everything came in today so I decided to go to work on all ARs and new lowers. Unbelievable easy but you can tell the difference between an expensive lower and a $49 lower when tapping it. Only lost 1 spring, really not lost but do not feel like moving a ton of $hit to get to it.
Thanks BigWaylon!
Thanks BigWaylon!