Modified or "cut" to Op Rod refers to the Stress Relief Cut applied to WWII Op Rods as a preventive measure to reduce risk of stress fractures at the handle-tube transition. Pictures show an example of where stress fractures were seen to occur in unmodified Rods Note that this was NOT a common occurrence. As a precaution, the Army issued an MWO (Modification Work Order) to have Op Rods in the field modified to prevent the possibility of cracking during use. The circular Relief Cut applied to WWII Op Rods is obviously for good reason but is no reason not to fire Rifles with unmodified Op Rods as many were not modified and continue to function fine to this day!! If the Army had really been worried, Uncut Rods would be rare versus as common as they are. DCM/CMP still issues Rifles to this day with Uncut / Unmodified Rods so have no fears using them.