▁longer ▁versions ▁are ▁typically ▁used ▁by ▁Law ▁En for cement ▁and ▁civil ian ▁h ob by ists . ▁A ▁Pic atin ny ▁Rail , ▁that ▁extends ▁over ▁the ▁length ▁of ▁the ▁bar rel , ▁accommod ates ▁a ▁variety ▁of ▁sight ing ▁and ▁ill um ination ▁access ories . ▁ ▁Rec ent ▁use ▁of ▁these ▁weapons ▁has ▁been ▁as ▁devices ▁to ▁non - le th ally ▁" stand ▁off " ▁pir ates ▁near ▁the ▁African ▁Coast . ▁ ▁Civil ian ▁use ▁include ▁Four th ▁of ▁July ▁celebr ations , ▁air port ▁run way ▁safety ▁( the ▁noise ▁sc ares ▁off ▁birds ) ▁and ▁wh ale ▁hunting ▁protest . ▁ ▁A ▁major ▁benefit , ▁compared ▁to ▁ 4 0 mm ▁launch ers , ▁of ▁this ▁system ▁is ▁that ▁it ▁requires ▁no ▁lic ens ing ▁( and ▁therefore ▁no ▁paper work ) ▁for ▁any ▁level ▁of ▁US ▁Government . ▁ ▁This ▁makes ▁it ▁a ▁relatively ▁easy ▁purchase ▁for ▁Police ▁and ▁First ▁Res pond ers . ▁ ▁Typ ical ▁r ounds ▁used ▁by ▁civ ili ans ▁with ▁this ▁launch er ▁include : ▁ ▁fl ares ▁ ▁smoke ▁r ounds ▁ ▁noise ▁effect ▁r ounds ▁( with ▁limited ▁det on ating ▁explos ive ) ▁ ▁To ▁avoid ▁classification ▁as ▁" dest ruct ive ▁devices " ▁under ▁B AT F ▁reg ulations , ▁r ounds ▁possessed ▁with ▁ 3 7   mm ▁launch ers ▁must ▁not ▁be ▁anti - person nel . ▁ ▁To ▁possess ▁these ▁one ▁must ▁get ▁a ▁tax ▁stamp ▁and ▁under go ▁investigation ▁by ▁B AT