So of the 3 guns that I cleaned today: One has GI guide rod. (Springfield Pro) One has a full length guide rod. (Baer SRP) One has a two piece full length guide rod. (Springfield TRP) I couldn't clean any of them without either an allen wrench or a plastic bushing wrench. All tight. I'm not really one to make a lot of changes if I buy something that I consider 'good' out of the box. The GI seems the simplest. Discuss.