I have some trigger time with the Saiga-12 but a lot more with a pump. Even a well trained pump operator will occasionally short stroke in a stressful situation. I wish I had time to do some hard study but I would say the malfunction rate of the Saiga-12 is about what I saw in malfunction rates for pumps - not high but you better train for it if you want to use it for that purpose. IMHO.
Correct a newbie if I am wrong...
It would be 922r compliant with any magazine if you use the Ace direct replacement stock with pistol grip as a unit, a US made Hammer and a US made sear?