I haven't tried the Super Colibris but have shot a lot of standard velocity shorts, BB cap and CB cap, all so quiet you can distinctly hear the hammer drop, someone not accustomed would think it a misfire. My Dad, born in 1905, claimed that as a kid he fired a lot of black powder .22s and shotgun shells. Said that a black powder .22 short would not penetrate both sides of a new tin can. Maybe cans were tougher in those days, probably they were, but a CCI .22 CB cap will breeze right through modern steel cans. I once though they would be good for dispatching trapped animals but found that from the 4" barrel of my S&W kit gun they would not penetrate the skull of a coyote, stunned him and I had to slip the muzzle right into his ear to finish him.
My dad insisted the .22 short was the only round fit for squirrel hunting, both because it did not disturb the whole woods with its' noise and he claimed it would push a head shot squirrel off the limb where long rifles zipped through, leaving the squirrel dead but still lying in the tree. Of course, he also insisted that the best way to thaw frozen fingers was to rub them with snow! I don't know about the "push effect" but shorts are quiet and I like that.