OMON's main weaponry consists of batons, shields and tear gas since they are riot police and are hated by majority of population for that role
They only carry serious weapons during tours and high risk raids. An old friend of mine serves in OMON. I was curious about use AKSU in real life after seeing that a lot of people prefer SU for their impressions. He told me that they have SU's but nobody really uses it anymore. At least in Moscow they don't. Sergey, that's the guy's name gets regular PM for city duty and had VSS during his tour. There are a lot of good weapons were developed in the last few years, especially large number of handguns but there is one problem, not enough money to rearm armed forces and police.
P.S SOBR was disbanded only on paper, it's called OMSN now. Same thing just different name. They still beat the hell out of anything that moves