I use a lone wolf barrel and this guide rod and spring http://www.efkfiredragon.com/glock-20-10mm-400-corbon-dual-action-recoil-spring-stainless-steel.html
Makes for one pleasant shooting glock and it can take any round you throw at it .
I got the lone wolf barrel primarily for case support but the ability to sling lead is pretty cool too .
" Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote. " - Benjamin Franklin
Thanks for all the info everyone! This sure helps. Especially since I picked it up today. Now I just need to grab some ammo for it.