Greetings:  One source of commercial ammo that seems to be usually available is Bitterroot Valley.  Several internet retailers sell it.  Bitterroot makes good quality 30-40 ammo in 3 bullet weights.  However, there is a problem with ALL commercial ammo that you may not know about yet.  Some unaltered Krags will only feed round nosed bullets unless you do them one at a time, but round nosed ammo does not seem to be easily available unless you reload.  You might buy one box of commercial ammo with pointed bullets and see if they feed.