From AllOutdoor.com:

GSG AK47-22 currently imported by ATI is the logical offering for the training market. Designed to mimic controls and overall feel of the 7.62 and 5.45 AK rifles, it appeals most to those who train CQB extensively and burn up significant amounts of ammunition in the process. However scarce and expensive 22LR has recently become, it is still far more affordable than centerfire ammunition. Rimfire ammunition also erodes range backstops substantially less, allowing indoor carbine training at pistol-only facilities.