The Karabiner 98k was a bolt-action rifle with Mauser-type action holding five rounds of 7.92x57mm Mauser on a stripper clip, loaded into an internal
magazine. It was derived from earlier rifles, namely the Karabiner 98b, which in turn had been developed from the Mauser Model 1898. The Gewehr 98 or
Model 1898 took its principles from the Lebel Model 1886 rifle with the improvement of a metallic magazine of five cartridges. Since the rifle was shorter than
the earlier Karabiner 98b from which it was derived (the 98b was a carbine in name only, being identical in length to the Gewehr 98 long rifle), it was given the
designation Karabiner 98 Kurz, meaning "Carbine 98 Short". Just like its predecessor, the rifle was noted for its reliability, good accuracy and an effective
range of up to 500 meters (547 yards) with iron sights.

The standard Karabiner 98k iron sights could be regulated for ranges from 100 m up to 2000 m in 100 m increments. The 98k rifle was designed to be used
with an S84/98 III bayonet and to fire rifle grenades. Most rifles had laminated stocks, the result of trials that had stretched through the 1930s. Plywood
laminates resisted warping better than the conventional one-piece patterns, did not require lengthy maturing and were less wasteful. Starting in late 1944, 98k
production began transition to the "Kriegsmodell" ("war model") variant. This version was simplified to meet wartime production demands, removing the
bayonet lug, cleaning rod, stock disk, and other features deemed to be unnecessary.

The 98k had the same disadvantages as all other turn-of-the-century military rifles in that it was comparatively bulky and heavy, and the rate of fire was limited
by how fast the bolt could be operated. Its magazine had only half the capacity of Great Britain's Lee-Enfield series rifles, but being internal, it made the
weapon more comfortable to carry. While the Allies (both Soviet and Anglo-American) developed and moved towards standardization of semi-automatic rifles,
the Germans maintained these bolt-action rifles due to their tactical doctrine of basing a squad's firepower on the unit's light machine gun and possibly their
problems of mass producing semi-automatic rifles.

In close combat, however, submachine guns were often preferred, especially for urban combat where the rifle's range and low rate of fire were not very
useful. Towards the end of the war, the Kar98k was being phased out in favour of the StG44 assault rifle, which fired a rifle round that was more powerful than
the pistol cartridges of submachine guns, but that could be used like a submachine gun in close-quarters and urban fighting. Production of the StG44 was
never sufficient to meet demand, being a late war weapon, and because of this the Mauser Kar98k rifle was still produced and used as the standard infantry
rifle by the German forces until the German surrender in May 1945.

Several special models of the Karabiner 98k existed
. For snipers, Karabiner 98k rifles selected for being exceptionally accurate during factory tests, were fitted
with a telescopic sight as sniper rifles. Karabiner 98k sniper rifles had an effective range up to 800 meters (875 yards) when used by a skilled sniper. The
German Zeiss Zielvier 4x (ZF39) telescopic sight had bullet drop compensation in 50 m increments for ranges from 100 m up to 800 m or in some variations
from 100 m up to 1000 m. There were also ZF42, Zeiss Zielsechs 6x and other telescopic sights by various manufacturers like the Ajack 4x, Hensoldt Dialytan
4x and Kahles Heliavier 4x with similar features employed on Karabiner 98k sniper rifles. Several different mountings produced by various manufacturers were
used. Approximately 132,000 of these sniper rifles were produced by Germany.

For Fallschirmjäger (German paratroopers) special versions of the Karabiner 98k that could be transported in shortened modes were produced. Specimens
with folding stocks as with unscrewable barrels are known.

The Mauser Kar98k rifle was widely used by all branches of the armed forces of Germany during World War II. It saw action in every theatre of war involving
German forces, including occupied Europe, North Africa, the Soviet Union, Finland, and Norway. Although comparable to the weapons fielded by Germany's
enemies at the beginning of the War, its disadvantages in rate of fire became more apparent as American and (to a lesser extent) Soviet armies began to field
more semi-automatic weapons among their troops. Still, it continued to be the main infantry rifle of the Wehrmacht until the end of the War. Resistance forces
in German-occupied Europe made frequent use of captured German 98k rifles. The Soviet Union also made extensive use of captured Kar98k rifles and other
German infantry weapons due to the Red Army experiencing a critical shortage of small arms during the early years of World War II. Many German soldiers
used the verbal expression "Kars" as the slang name for the rifle.