These pellets seem just too light. When I was reading about them, I was getting really excited because of all the benefits. But then I read the weight, and it just ruined the pellets for me. I dont think I even want to try them on my Gamo (by the way, my Gamo has a custom made Delrin guide, so it should be as hard as metal, but it is actually plastic). Everything I have read says that magum air rifles should not shoot pellets weighting less than 7 grains, and these are just WAAAAAAAYYY below that... Plus, in all my research, lighter pellets do have higher muzzle velocities, but energy falls much faster than heavier pellets as distance increase, so even though they show higher energy at the muzzle, the actually reach the target with less energy (and energy, and not velocity, is what kills the prey!!!).
Also, the fact that they are made from a harder alloy is good when hitting the target, but I dont know how good that is for skirt expansion... In short, these pellets just bring out too many IF's so I think I'll just let others experiment, and I will stick to what I know works!
By the way, to the anonymous poster, one possible reason why they may sound like a .22LR is because what you are hearing is the piston slaming into the receiver at a much faster speed than what is normal, so carefull!
Thanks for everyone's opinion!