I did a test as well. I happen to own an air-pressured BB gun, modeled after the Colt M1911.
In case the British government sees this and demands a loicense: I'd like to declare that I do not have the British nationality nor do I live in Great Britain. Get stuffed.
Where I live this is perfectly legal as long as you don't go out waving them around in public like an idiot, and anyone over 18 can just buy these things at a hardware store, the same place where I bought my lawnmower. We have a high-trust society here, it's all for sport.
Vi forhandler et stort udvalg af luftgeværer og -pistoler til skydetræning. Mangler du en skydeskive, hagl, kikkertsigte, nyt magasin eller andet tilbehør, så har vi også det.
www.harald-nyborg.dk
I have this set, to be precise.
Luftpistol med justerbart sigte og Pump- og Single-shot affyring. Sættet består af: Luftpistol. 500 stk. 4,5 mm. hagl. 100 skydeskiver. Hagl størrelse: 4,5 mm. Udgangshastighed 4,5 mm hagl: 91 m. sek. Luftgevær og luftpistoler sælges ikke i vores webshop og ikke til personer under 18 år.
www.harald-nyborg.dk
Now that we have that out of the way, I loaded up a single 4.5 mm pellet with a pointy tip. I don't have a 500-pack of printer paper laying around, but I don't expect much damage from this BB gun, so a simple notepad will do.
As expected, the number of sheets these tiny projectiles go through is very low. The shot I took only (barely) punctured through 7 of them with the tip, denting the 8th. Then it just bounced off right back to me.

The distance was only about 5 meters.
(it's hardly even visible, lol)