+1 on the CCI CB's.
I prefer the CB Longs, though the CCI Shorts are EXACTLY the same bullet, powder charge, ballistics. The longs tend to give me slightly better accuracy, as the bullet gets seated further into the chamber...the shorts won't cycle in a few of my rifles, either.
Otherwise, they sound/shoot equally.
The pity is EVERY shop carries the CB shorts, but only walmart in my area has CB longs...and walmart wants $1 a box more than the shorts found everywhere else. Oh well!
I don't shoot the Aguila Colibris anymore...but I do still have a brick of Super Colibris.
I've had a handfun of colibris stick in the barrel, but all the super colibris have made it out....the problem is accuracy--it just doesn't seem to be there with the colibris. Too much variation.
The CB Longs work well around the farm--don't spook the cows, and are plenty for crows/barn pigeons and even bunnies. I keep 'em within 30-40yds, though. Never had any of the above make it more than a few feet after been whopped with a CB.
All my rifles are more quiete with the CB's than my spring powered air rifle.
Great round of kids as well--accurate enough they aren't frustrating, but quiet enough to shoot without hearing protection so they can hear ALL your tips/commands.