Air pistolsareusingspringpistonandthepiston isclosedwithnitrogenat the edge ofa flangebearing.These gunsarmby breaking thebarrel andanchor thepistonin the mechanismof the trigger.By pressingthe triggeris releasedthe springornitrogenpistoncompresses the airinside thecasing,givingenergy tothe bulletfired.Thehandairgunsof the spring,because of their smallvolume,it is not possibleto give ushigh speeds,nor canbeiteratively, and thenitrogentogivethe pistonalmost doublespeeds.Thespringhaving a good shot around10 meters, while those withthe nitrogen pistonmost bigger and is completelyautonomous.