In Slovic Countries (i.e. ones that speak Russian-derived languages) This is slang for penis. This started in a translation to a viral video, DongCopters, in which Garry Kasparov (Russian Presidential canidate) slew the mighty flying penis and united all of Russia with a picture of his 5.3 inch 'Russian Artillery'. It has been in heavy use ever since.
And if you look to the monitor on your left, you will see our entire arsenal - five point three inches of Russian Artillery! It may be small, but notice the girth!
I saw you go home with Anna yesternight.
Yeah, I slipped her some of the ol' Russian Artillery.