i have shot the hell out of steel cased ammo. even hornady is making steel cased ammo these days.
the only real worry i have about russian made ammo is that they often use steel-jacketed bullets which may wear out a "soft" barrel a bit quicker. the rate of twist also has something to do with it. a chrome plated bore 1in 9 inch twist should run a long long time-
i have been firing com-block ammo for a long long time from the AR-15 platform with very few issues. any AR that won't run it-- needs work.
i don't see any reason not to use in in the su-16s--esp if they have a chromed bore.