There are reports of cracked frames from using 9mm Largo that was apparently made for sub machine guns or Destroyer Carbines. I have 3 types of 9mm Largo from Spain. One of the 3 is marked "para pistola o sub-fusil" which translates to pistol or automatic rifle. In Spanish is automatic rifle the term for a sub machine gun? The letter o in lower case is always "or" when used to indicate "both". The second is marked 9mm Largo para Pistola automatica, Carabina y Sub-susil. The 3rd is marked only 9mm Largo and made in 1981 non corrosive by Santa Barbara. Can anyone help us with this issue? It would be interesting to hear if anyone has see 9mm Largo marked for "Automatic Rifle only". Thank you.