What 0.5? If you mean the force, 0.5 joules for an airsoft gun is average. If you mean the weight of the BBs, its depend on the speed (fps) of the BB. 0.5 gr BBs is very uncommon/rare.
Soft Light - The X-Files - was created on 1995-05-05.
Cedric van der Gun was born on 1979-05-05.
Hudson Soft was created on 1973-05-18.
Love Gun was created in 1977-05.
Annie Get Your Gun was released on 05/17/1950.
This Gun for Hire was created on 1942-05-13.
The Gun Song was created on 2008-05-18.
Richard Gun was born on 1936-05-27.
The Gun Packer was created on 1919-05-24.
Man with the Gun was created on 1955-11-05.
Grab That Gun was created on 2004-05-24.
Bullets in the Gun was created on 2010-10-05.