If there is a roll pin directly over the trigger, than it is an easy open frame. They came that way from the factory starting with SN 195,000 but some of the older ones have been modified. Some of the earliest barrels had a flat lug, later barrels have a stepped lug. I've heard (but have never seen it) that some of the earliest frames can only use the flat lug barrels and vice versa. T/C will fix whatever you have to make it work with all barrels. If all your frames are easy-open and your barrel has a stepped lug, than you probably have a bolt height problem. T/C will fix it, but you can do it yourself if you can work a file. If you have a non easy open frame and slightly high lugs, you may not be able to exert enough force on the trigger guard to push the split bolts on a newer barrel. Also if the bolts a just a little low and engage too far and the part of the frame they lock up on is sharp, it can dig into the bolts as you try to disengage them. If it were my stuff, I'd take the trigger group out of the frame and check the ramp and the depth the bolts engage, then reinstall the trigger group to remove the barrel. Alternatively you can ink the tops of the bolts and try it that way, but removing the trigger group is pretty easy if you have the exploded view. (if you need it I can e-mail it to you).
Bill
