They sent in the A team it looks like. Russia’s version of the Marine Corpse
US Marines never get the latest and greatest of anything.
Almost all hand-me-downs.
They complete their missions the old fashioned way...ground assault backed by mechanized infantry and close air support.
I expect you'll see similar effectiveness and valor on the part of the Russians in Syria.
The FSB will be running Mosul in 6 months or less, with ISIS relegated to Anbar province in Iraq. Syria will be cleared of them.