Reply To: .22 Verses .20
I think the .20 got popular with spring rifle shooters simply because the power limitations of most spring guns. If you were shooting a .177 your shots were coming out faster and you had a flatter trajectory. If you were shooting a .22, which has more knock down power for hunting than a .177, your shots were coming out slower and you had a more loopy trajectory. I think the .20 was just meant as a compromise between the two.
With the power of today’s PCP that is not a compromise that has to be made any more. The only advantage with .20 that I can think of is that you might get a few more shots due to needing a bit less air. The difference however would not be worth it to me lose the selection of ammo that is available in .22 and the .22 will have a better balistic coefficient and be better for longer range shooting. I would take the .22 and not look back.
All the best,