I can offer you my opinion as I have 3 .20 cal. Rifles. The lack of pellet choice in .20 is a large hindrance . I stumbled on these guns used. If I were to buy new, I would forgo the .20 altogether. That being said, you can buy a barrel at any time, in any of the three calibers and simple install on to your action. I just ordered a .177 barrel for my R7. It is currently a .20