Very carefully as their are many counterfeits extant, as the 28 gauge was built on the same receiver as the 16 and 20 gauge M12-- lots of solid was to tell a real one from a counterfeit- safest ways are two-- (1) Remove the buttstock from the receiver- the original factory gauge stamping will be found at the rear inset of the receiver- where the head of the stock mates into the ring shaped boss- secondly- look carefully at the magazine ring- the M12 in 28 gauge was mfg. from 1937 to 1954-- as WRA got closer to the end of production of the "Perfect Repeater" they went from a forged steel alloy magazine ring, stamped with 28 that should face reward when properly installed, to a lost-wax or investment casting magazine ring, which will have a grainy appearance, and the 28 gauge in different script and facing reward- so counterfeiters mixed up the parts when they cobbled together their "fake" 28 gauge guns to sell to the unwary- The extractor, ejector and firing pin are also different in the true 28 gauge, as compared to the 20-16 and of course, the 12 gauge guns- About 5 years ago I bought from a private party- a 1939 field grade M12 with 28" solid rib barrel, WS-2 choked, 28 gauge with 2& 7/8" chambering- NOT a skeet gun, but for some reason, choked Winchester Skeet 2-- special order? Who knows-
