The TKB-517 (Russian: ТКБ-517) is an assault rifle designed by . This rifle was externally similar to the AK-47, but based on the lever-delayed blowback mechanism invented by John Pedersen and refined by Pál Király. It turned out to be more reliable, more accurate and controllable under full auto, and easier to produce and maintain. Like the AK series, it was also manufactured with folding stocks, longer, heavier barrels with bipods (forming light support weapons) and even a belt-fed variant. Its rejection was because of a greater proficiency with the AK-47 among the Russian military, though it is just as likely it was rejected due to relatively high extraction pressure, which is a common issue firearms using lever-delayed blowback actions.