On a somewhat related note, the Austrilians used to line up a load of Vickers .303 machine guns (something like 30 to 50 of them) and fire them at a target like artillery. Used to do it during the New Guinea Campaigne.
Those that saw it operate said it was awesome. Just belt fed, water cooled machine guns firing away for 10 minutes.
The British did something similar with the Vickers in WWI, firing themindirect over special sights to rain fire into German trenches. It was often used to supress German troops while British infantry advanced on thier positions.
In terms of the Russian weapon, I can't see it being much use, IMHO. As someone already stated, infantry tend to bugger off sharpish when aircraft appear, so it would be hard to get a massed target, although it might be useful against soft vehicles. Either way, the attacking a/c would have to get very low - and SMG is only effective over very short ranges. This would expose the attacker to fire from infantry small arms as well as AAA assets - not a good place to be under any circumstances.