Originally Posted by ignantmike
no need to change anything else......just drop it in and shoot
I've done this conversion my self. I bought a different brand barrel, but a barrel is all you need. .40 feeds just fine out of the G20 mags. In fact, I've never had a single failure using .40 in my G20, but I've had lots of trouble shooting 10MM out of it. My .40 barrel is an extended & threaded Bar-Sto.