▁Bl aser ▁R 8 ▁and ▁R 9 3 ▁which ▁uses ▁an ▁expand ing ▁col let ▁in ▁a ▁similar ▁fashion . ▁ ▁Mechan ism ▁Rol ler ▁lock ing ▁is ▁used ▁by ▁the ▁C Z ▁ 5 2 ▁p istol . ▁S lide , ▁bar rel , ▁lock ing ▁piece ▁and ▁roll ers ▁are ▁shown ▁here . ▁ ▁Norm ally ▁the ▁re co il ▁spring ▁push es ▁the ▁lock ing ▁piece ▁rear ward , ▁which ▁in ▁turn ▁push es ▁the ▁bar rel ▁back ▁and ▁holds ▁the ▁lock ing ▁roll ers . ▁( In ▁some ▁of ▁these ▁pictures ▁the ▁spring ▁is ▁removed ) ▁ ▁When ▁the ▁gun ▁is ▁fired , ▁the ▁bar rel , ▁slide ▁and ▁lock ing ▁piece ▁( right ▁side ▁of ▁picture ) ▁will ▁move ▁backwards ▁a ▁short ▁distance , ▁while ▁the ▁lock ing ▁piece ▁will ▁be ▁stopped ▁by ▁a ▁tab ▁on ▁the ▁frame , ▁shown ▁on ▁the ▁left ▁with ▁a ▁stick ▁pointing ▁out ▁the ▁m ating ▁surface . ▁▁ ▁With ▁the ▁lock ing ▁piece ▁stopped ▁by ▁the ▁tab , ▁the ▁roll ers ▁will ▁continue ▁rear ward ▁with ▁the ▁slide , ▁until ▁they ▁reach ▁the ▁re cess ed ▁portion ▁of ▁the ▁lock ing ▁piece . ▁The ▁roll ers ▁will ▁then ▁be ▁allowed ▁to ▁move ▁in ward , ▁and ▁will ▁release ▁from ▁their ▁indent ations ▁in ▁the ▁slide ▁re le asing ▁the ▁slide ▁from ▁the ▁bar rel . ▁ ▁At ▁about ▁the ▁same ▁time , ▁the ▁bar rel ▁will ▁be ▁stopped ▁by ▁the ▁lock ing ▁piece . ▁M oment um ▁will ▁carry ▁the ▁slide ▁back