▁and ▁tight ened ▁fire arm ▁lic ens ing ▁rules . ▁The ▁law ▁requires ▁anyone ▁wish ing ▁to ▁possess ▁or ▁use ▁a ▁fire arm ▁with ▁some ▁exceptions , ▁be ▁over ▁the ▁age ▁of ▁ 1 2 . ▁O wn ers ▁must ▁be ▁at ▁least ▁ 1 8 ▁years ▁of ▁age , ▁have ▁secure ▁storage ▁for ▁their ▁fire ar ms ▁and ▁provide ▁a ▁" gen u ine ▁reason " ▁for ▁doing ▁so . ▁ ▁Effect iveness ▁ ▁In ▁ 1 9 9 7 , ▁the ▁Prime ▁Minister ▁appointed ▁the ▁Australian ▁Institute ▁of ▁C rimin ology ▁to ▁monitor ▁the ▁effects ▁of ▁the ▁gun ▁buy back . ▁The ▁inst itute ▁has ▁published ▁a ▁number ▁of ▁papers ▁reporting ▁tr ends ▁and ▁statistics ▁around ▁gun ▁ownership ▁and ▁gun ▁crime , ▁which ▁it ▁has ▁found ▁to ▁be ▁mostly ▁related ▁to ▁il leg ally ▁held ▁fire ar ms . ▁A ▁ 2 0 1 3 ▁report ▁by ▁the ▁Australian ▁Crime ▁Commission ▁said ▁a ▁conserv ative ▁estimate ▁was ▁that ▁there ▁were ▁ 2 5 0 , 0 0 0 ▁long ar ms ▁and ▁ 1 0 , 0 0 0 ▁hand g uns ▁in ▁the ▁nation ' s ▁ill ic it ▁fire ar ms ▁market . ▁The ▁number ▁of ▁guns ▁imported ▁to ▁Australia ▁leg ally ▁has ▁also ▁ris en . ▁A ▁ 2 0 1 4 ▁report ▁stated ▁that ▁approximately ▁" 2 6 0 , 0 0 0 ▁guns ▁are ▁on ▁the ▁Australian ▁' gre y ' ▁or ▁black ▁mark ets ". ▁ ▁Research ▁by ▁Philip ▁Al pers ▁of ▁the ▁University ▁of