This isn't even really an "anti-gunner" problem at all.
- As it's stated, he's 16, what he thinks does not matter at all. Don't let it worry you. Let WHY he acts this way worry you.
- With his limited social life, and being in his older 19 y.o. brother's shadow, he has a massive inferiority complex and low self esteem.
- He's deliberately taking on a belief system/persona to irritate you, and get negative attention out of you. This is not completely conscious on his part.
- He's obsessive about another culture, where your family history is, (Russia) because he's got a very deep need to self-identify with something. This is tying into his low self-esteem and social isolation.
Mentally, he's flirting with the mindset that the Columbine kids had. They felt so lost, outside, and like losers, that they deliberately identified with negative cultures and things in history. Harris and Klebold chose Hitler, your little brother is focusing in on the negative totalitarian aspects of Communism which has a tie in to your Russian family heritage. It's a way of saying "F'-it all…I quit! I'm one of the bad guys!" way of throwing in the towel on normal life in which he feels a failure, yet the violence and dominance in that evil/totalitarian culture has something that makes him feel empowered at the same time.
If it's a mild case, your little brother needs a broader social life and a girl, if it's worse, he needs some counseling/help/medication.