There was a "sportsman" model of the chinese sks back in the very early 90's that I. Picked up from lever arms in vancouver.
It came with the typical sling and kit, as well as 2, short mags. I think they were 5 rounders. This rifle had no bayonet and featured a much beefier chinese stock with rubber buttpad and cleaning rod under the barrel.
The action was a modified fixed mag sks with standard , slide tab mag release, welded bolt stop, milled for forward mag lip.
It functioned great withe short mags, flawless in fact.
However 30 round AK mags would drop out of the gun under recoil as the mag catch was inadequate for the weight of the mag.
The conversion would be very simple for someone with some skill and the right tools.