▁the ▁M ini - 1 4 ▁rif le ▁emp lo ys ▁an ▁invest ment ▁cast , ▁heat - tre ated ▁receiver ▁and ▁a ▁version ▁of ▁the ▁M 1 / M 1 4 ▁rif le ▁lock ing ▁mechanism . ▁Although ▁the ▁M ini - 1 4 ▁looks ▁like ▁the ▁M 1 4 , ▁it ▁util izes ▁a ▁reduced - size ▁operating ▁system , ▁a ▁different ▁gas ▁system ▁and ▁is ▁chamber ed ▁for ▁the ▁smaller ▁. 2 2 3 ▁cart ridge . ▁ ▁Spring field ▁Arm ory ▁commercial ▁production ▁ ▁In ▁ 1 9 8 2 , ▁years ▁after ▁the ▁closure ▁of ▁the ▁U . S . ▁Spring field ▁Arm ory , ▁a ▁commercial ▁firm ▁– ▁Spring field ▁Arm ory , ▁Inc . ▁– ▁began ▁production ▁of ▁the ▁M 1 ▁R if le ▁using ▁a ▁cast , ▁heat - tre ated ▁receiver ▁with ▁serial ▁numbers ▁in ▁the ▁ 7 , 0 0 0 , 0 0 0 + ▁range , ▁along ▁with ▁commer cially ▁produced ▁bar rel s ▁( mark ed ▁Gen ese o , ▁IL ) ▁and ▁G . I . ▁military ▁sur plus ▁parts . ▁ ▁Civil ian ▁use ▁ ▁United ▁States ▁citizens ▁meeting ▁certain ▁qual ifications ▁may ▁purchase ▁U . S . ▁military ▁sur plus ▁M 1 ▁rif les ▁through ▁the ▁Civil ian ▁Mark sm ans hip ▁Program ▁( C MP ). ▁The ▁C MP ▁is ▁run ▁by ▁the ▁Corporation ▁for ▁the ▁Prom otion ▁of ▁R if le ▁Pract ice ▁and ▁Fire ar ms ▁Saf ety ▁( CP R P FS ),