Markings: The import mark on the barrel reads “BLUE SKY/ARLINGTON, VA.”. There are no specific dates for Union Switch & Signal receivers as their deliveries were late to NPM (page 29 of Scott Duff’s book The M1 Carbine Owner’s Guide).Īction Type: Semi Auto, Detachable Magazine Union Switch & Signal produced the receiver under contract for National Postal Meter (NPM). Arrow_back Return To All Sold Items arrow_back Return To Sold Post-1900 U.S.
