At the end of When Germany capitulated in 1945, there were nearly 400,000 German soldiers in Norway (largely thanks to the efforts of the Norwegian Resistance to prevent them from being transferred south). This provided Norway with a massive supply of K98k Mauser rifles to reequip their armed forces, and they picked about 250,000 of the best condition guns (mostly early war production, naturally) to take into service. These rifles were repaired and refurbished as necessary, and given new Norwegian serial numbers on the receivers, bolts, and buttplates. They were also modified to have "U"-notch rear sights and square post front sights.
In 1953 and 54, the a program was undertaken to rebarrel the rifles from 8x57mm to .30-06 (7.62x63mm) in order to be able to use supplies of .30-06 ammunition made available by the United States. While the Norwegian Navy retained its 8mm chambering, all the other service branches had their rifles modified to use the new cartridge, and these rifles were given the new designation m/K98kF1. A second rebarreling was begun years later to convert rifles to the new 7.62mm NATO cartridge, but this was quickly abandoned and the G3 rifle adopted instead, with the Mauser going into war reserve by 1973.
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