Here is a  U.S. M1 30 caliber semi-auto carbine manufactured by the I.B.M. Corp. with serial #3727968 on the receiver. This carbine has an 18" long "I.B.M. CORP. / 10    -43 / (flaming bomb)" marked barrel with a bright bore. The carbine features a four rivet handguard stamped "IO" on the underside and a high wood pistol grip stock that rate very good having been moderately sanded and refinished. This carbine has the Type B safety, unmarked Type C operating slide, Type B magazine release stamped "EP B", Type B front band, Type C recoil plate stamped "AU" on the right side, Type B trigger housing stamped "BE-B", an "AM B" marked Type C hammer, and a non adjustable rear sight marked "IN B" on the right side and "S" on the left side. The metal surfaces retain most of their thinning military type of gray finish with a few specks of pitting on the barrel. The wear is mostly on the barrel and the usual areas based upon action usage. The breech bolt has more of a darker blue / black finish with similar wear and the butt plate appears to have been cleaned to a gun metal gray. This carbine includes a commercial manufactured 15 round metal magazine. A nice example for an International Business Machine Corporation M1 Carbine.  {C&R}