For how many seconds? The bb guns I had would do damage at no more 100ft=0.1 sec.
The actual muzzle velocity of most adult grade spring air rifles is between 1,000 fps and 1,200 fps for .177 cal. pellets, right up there with some .22 LR ammo. Go to
www.cabelas.com
and see for yourself.
I reload A LOT of ammunition, so I own a chronograph.
I was curious about the Daisy Red Rider BB guns that I bought my girls for Christmas, so I set up the chrony for some testing.
About 274 fps with the most recent version of the Red Rider. Not bad and a hell of a lot of fun for the kids.
Are they slightly dangerous? Yep, but the pellets are easily contained within a average sized yard, will not shoot through metal, thick wood or other materials.
To outlaw air guns is the height of stupidity.
However, air guns of large caliber, which are outlawed pretty much across the US, could be as dangerous as a real firearm, .50 or above would be deadly, and in fact at one time air guns of such size were used. Lewis and Clark, for instance, carried a number of air guns of large caliber with them on their famous expedition. Not only were they large caliber they were repeaters, something real firearms of the time were not.
My RWS (Dana) model 40 does 1170 fps. I love this gun.