Locally we had a brother kill his sister with one of those bb/pellet guns. If it can kill, it does not need to be colored as safe (red tipped).
http://www.newschannel9.com/video/?videoId=1315742659&lineupId=&play=now
i have a lot of boys and a lot of bb and pellet arms...as well as the real stuff
the Red Ryder stuff is weaker than in my day..bounces off sparrows...think Lassie or My Three Sons era for me...all boys had guns then...now moms keep them lassoed up with video games pretending instead of doing...like their daddies come to think of it..lol
the BB pistol...which is metal btw...will sting you good
the Benjamen and Crossman pellet shooting arms in either .177 or .22 will hurt but they have been tuned down to less pressure given per pump...we used to be able to pump up to squirrel lethal in about 7 pumps...now it's much harder
I have a Crossman .177 1955 commemorative pellet pistol that is much stronger with the CO2 than the later ones
I have seen someone shot with a .22 Benjamen...not likely lethal but can put your eye out or lodge near the spine..as in the case I saw
They do make larger barrel rifles now in air that will shoot I think 1500 fps or so in .22....not sure I would call that a medium or large game rifle but good for some varmints at reasonable range with a distress call I guess
I am not aware of larger air guns though they may be out there...the higher velocity ones are not cheap