The AEK-971 (Russian: Автомат единый Кокшарова 971, "Automatic (rifle), Universal, (of) Koksharov, 971) is a selective fire 5.45×39mm assault rifle that features a balanced automatics recoil system, developed at the Kovrov Mechanical Plant (KMZ) by chief designer Stanislav Ivanovich Koksharov (Cyrilic: Станислав Иванович Кокшаров), also known as Sergey Koksharov, in the late 1970s and 1980s (currently manufactured by Degtyarev Plant). Variants in 5.56×45mm NATO (AEK-972) and 7.62×39mm (AEK-973) were also developed.

The 6P67 KORD and 6P68 KORD were developed for the Ratnik trials on 23 December 2014 and are based on the AEK-971 and AEK-973 respectively. The 6P67 KORD and 6P68 KORD feature numerous internal and external improvements over their predecessors and were later adopted by the special forces units (Spetsnaz) of the Russian Armed Forces.

The AEK-971 was developed to participate in a competition announced by the Ministry of Defense of the USSR, during which preference was given to the AN-94. The prototype of the AEK-971 differs from the production model, as many innovations were perceived as unnecessary by the Ministry of Defence, which led to a simplification of the prototype. Initially, the prototype featured a 2-round burst mode, which was later changed to a 3-round burst mode in the production model. The AEK-971 is approximately 0.5 kg (1.1 lb) lighter than the AN-94, simpler in design and cheaper to manufacture.

The AN-94, which was officially adopted by the Russian army, has a slight accuracy edge over the AEK-971 in its 2-round-burst mode. However, in full automatic mode or during longer bursts (3–10 rounds per burst), the AEK-971 is more accurate. Although it lost the initial production contract to the AN-94 as a result of the Project Abakan assault rifle selection trials held in Russia from 1980 to 1994, the Russian Army still began field trials for the AEK-971.

The AEK-971 has been combat proven in Chechnya tested by naval infantry and interior forces, and prepared for mass production. Only a few small batches of the AEK-971 have been produced so far and adopted for service with units of the Ministry of Justice of the Russian Federation.

On 23 December 2014, the Russian Army announced a variant based on the AEK-971, designated as the 6P67 KORD (official GRAU designation 6P67), along with the AK-12 had both passed (Ratnik) state trials and would be accepted into service and set for evaluation with operational units in early 2015. Both systems were recommended for initial batch production and issue for trials in the field. It is possible that in the end both rifles will be adopted by Russian military and other agencies, with the AEK series being oriented towards Special Operations Forces (Spetsnaz) and AK-12 towards infantry and other units. It was expected that both rifles would be tested operationally with the Russian military by March 2015.

In March 2017, it was revealed that the 6P67 KORD would be accepted into Russian service after testing was completed along with the AK-12, although serving border patrol regiments, special forces, and the national guard due to its more complicated and expensive design while the AK-12 would arm regular infantry forces.

In January 2018 it was announced that the 6P67 KORD has been adopted in 5.45×39mm and 7.62×39mm chamberings by the Russian military.