They also have some interesting features on their tanks. The T-80U and T-90 can fire both 125mm tank rounds and guided missiles through the main barrel. And they have a system to defend against missiles that attack down on the tank - pretty neat, basically a ring of claymores to destroy the missile, triggered by a radar sensor.
BTW, I believe Mexico was the first country to adopt a semi-auto rifle - the Mondragon. However, IIRC, the Russian Federov rifle preceded our BAR (similar concept).
I don't think they're technically ahead of the US, they just design their weapons for different needs. Where we believe in surgical strikes and minimal losses, they simply throw enough troops and artillery at a problem to make it go away, whatever the cost. Where we have a relatively highly-educated and technically adept military, their military has historically consisted of umpteenth-generation peasant farmers (no insult intended) with little to no formal education. We also have a ratio of about 10 support troops for every combat soldier - something unheard of in Soviet/Russian military; they just don't have the depots, armorers, etc. maintain complicated/fragile weapons. Soviet/Russian equipment has to be practically industructible, or it's worthless. Their rifles are designed to function when frozen, dropped in mud, used for a prybar, hammer, etc. and their jet fighters are made to be serviced by guys who just polished off a bottle of vodka in 30 below weather. All that being said, the Russians are exceptionally good at "making do" with what they've got, and their designers are no exception. I think it's something we've lost a bit of as our society, and therefore our military, has become more urban and less self-reliant in the last 50-60 years.
One of my favorite quotes about Soviet equipment was written by a Western observer about the T-90 tank - he said it was "Designed by geniuses to be used by morons." That about sums up the Russian weapon design philosophy.