All that it takes to put Russia in real problems is that US and its anti Russian alliance send 30,000 strong Special forces ,armed to the teeth with all modern NATO weapons ,
including long precision range artillery , NATO tanks and thousands of modern top attack anti tank weapons like SPike or Javeline ,to put the rebels in serious trouble and over run their positions. Since they are mostly using old weapons and old tanks.
Russia has no stake in the conflict... if US forces take all of the Ukraine then that is no problem for Russia... the Ukraine has been anti russia for some time... so US occupied Ukraine wont be much difference.
There is plenty Russia could do from arming rebels, through to simply stating that US interference and occupation of Ukraine will lead to Russia withdrawing from the New Start Treaty and the INF treaty and that Russia will start making new nuclear warheads at a rate of a few hundred a year to ensure the security of Russia.
Any attempt to retake the Crimea would be an attack on Russia which would lead to full retaliation up to and including nuclear weapons.
The US can also arm chechens with modern weapons or OverRun tajikistan with re-deployed
ISIS mercenaries..
Russia could do the equivalent... arm native americans, mexicans, al quada... and fully support independence causes in Europe like Scotland, the basque separatists etc etc. Even old MANPADS are quite effective... as are ATGMs.
Russia needs Armata tanks this year.. at least a couple of hundred.. and not in 2018.
What Russia does not need is half tested prototypes in service when they are not ready yet...
Now is when they need them.. You also have the Syria war.. that last information says a major war will start soon there ,with NATO vs Syria.
Rubbish... they may never need them... and for Syria the upgraded T-72BM3s will be excellent with very good communications equipment and thermal sights...
Russia is on a state of war and they act as if.. nothing happens and the war is not against them.
For all its strength the west is actually rather weak when it comes to opposing nuclear powers... in the end they will huff and puff and do very little.
Russia can support Syria with all sorts of new presents and test all sorts of new weapons in Syria... it has plenty of potential... likely once Iraq and Iran have dealt with ISIS on their territory they might be pursuaded to assist Syria with its ISIS problem.
You just need to calm down Vann.... the US sending 30,000 spec forces to the Ukraine will just get a lot of them killed.
An interesting hypothesis from the Defence Update analysis
It is Kord... 12.7mm.
The numbers is just replication of old Soviet system of identification using rear facing lights with stencilled numbers for ID of unit.