A:
NO, MAGNUM IS A SELLING PIONT ADDED TO A WEAPON. AS LONG AS YOUR AMMO IS THE SAME GAUGE AS THE GUN IE.. 12 GUAGE USES 12 GUAGE AMMO ECT.. 3 INCHES IS THREE INCHES, BUT GIVIN MAGNUMS HIGHER PRESSURES I WOULD MAKE SURE THE GUN IS IN GOOD CONDITION. IF ITS A RELIC OR YOUR STILL CONCERNED I WOULD CONSULT YOUR LOCAL GUNSMITH..