Imagine you're in a Swiss Shoot in Swizterland, where there are hundreds, if not thousands of other shooters. Great majority of shooters are using Swiss military weapons. Maybe half of those are using K31s. How do you find yours in the rack?
I often use red tape in the same manner when attending a major Swiss shoot to see where all our clubs rifle are. Some use Black, Blue, Yellow, etc.
The Swiss Federal shoots do mandate that arms have to be inspected to insure compliance with the rules( mostly trigger pull weight and safe sear engagement) . Once inspection is passed, the rifles get PAPER STICKERS like the yellow and red ones you see in this picture:
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There were NO K31s made in 1932.
1932
K11s were ser.# range 202001 to 2112000.
Does yours have a red plastic bolt handle?
A space equal to the trigger guard between the trigger guard and magazine?
That is a K11, if so.
Model 1931 Carbines (Karabiner)
Year, Quantity, Serial numbers
1933 1193 520010-521202
1934 15534 521203-536736
1935 13664 536737-550400
1936 11326 550401-561727
1937 11639 561728-573366
1938 10344 573367-583700
1939 15300 583701-599000
1940 33575 599001-632575
1941 54150 632576-686725
1942 49350 686726-736075
1943 50475 736076-786550
1944 51900 786551-838450
1945 26200 838451-864650
1946 15600 864651-880250
1947 20950 880251-901200
1948 20100 901201-921300
1949 15500 921301-936800
1950 13200 936801-950000
1951 23050 950001-973050
1952 21400 973051-994450
1953 5549 994451-999999
1953 7450 215001-222450 * note change in Ser.#
1954 17150 222451-239600
1955 11250 239601-250850
1956 6400 250851-257250
1957 2950 257251-260200
1958 3130 260201-263330