▁unique ▁case ▁designed ▁by ▁Horn ady ▁and ▁R ug er ▁based ▁on ▁the ▁powerful ▁. 3 7 5 ▁R ug er ▁cart ridge . ▁The ▁case ▁is ▁of ▁a ▁rim less ▁design ▁having ▁the ▁base ▁and ▁rim ▁diameter ▁of ▁ ▁which ▁is ▁the ▁same ▁diameter ▁of ▁the ▁bel t ▁on ▁bel ted ▁mag num ▁cases ▁based ▁on ▁the ▁. 3 0 0 ▁H & H ▁Mag num ▁and ▁. 3 7 5 ▁H & H ▁Mag num . ▁This ▁allows ▁the ▁cart ridge ▁to ▁have ▁a ▁greater ▁case ▁capacity ▁than ▁a ▁bel ted ▁mag num ▁case ▁given ▁cases ▁of ▁equal ▁length . ▁As ▁R ug er ▁intended ▁the ▁cart ridge ▁to ▁be ▁chamber ed ▁in ▁short ▁length ▁b olt - action ▁rif les ▁the ▁case ▁length ▁was ▁short ened ▁to ▁ ▁which ▁is ▁similar ▁to ▁the ▁. 3 0 8 ▁Win chester ▁case . ▁Un like ▁Win chester ▁Short ▁Mag num ▁cart rid ges , ▁the ▁R ug er ▁Comp act ▁Mag num s ▁share ▁the ▁same ▁diameter ▁from ▁case ▁head ▁to ▁body . ▁This ▁allowed ▁R ug er ▁to ▁chamber ▁the ▁cart ridge ▁without ▁extens ively ▁red es ign ing ▁their ▁M 7 7 ▁rif le ▁to ▁adopt ▁them ▁to ▁the ▁new ▁R ug er ▁cart ridge . ▁ ▁While ▁the ▁. 3 0 0 ▁H & H ▁Mag num ▁is ▁longer ▁than ▁the ▁. 3 0 0 ▁R ug er ▁Comp act ▁Mag num , ▁the ▁latter ▁cart ridge ▁has ▁a ▁greater ▁case ▁capacity ▁than ▁the ▁former . ▁This ▁is ▁due