Did the National Guard use M-1 rifles at Kent State in 1970?

No the National Guardsman at Kent State University that day only had live ammunition. Why they even fired in the first place is very questionable. However ignoring that controversy the enquiry into the murders concluded that the National Guard shold never again carry live ammunition to student protests. The development and use of rubber bullets since then by military and police in the US has resulted from the tragedy at Kent State to give a non lethal option to Troops and Police.