Yes, AUTOMATICS is a Scrabble word!

Letter values in Scrabble US: A 1, U 1, T 1, O 1, M 3, A 1, T 1, I 1, C 3, S 1.

Is it a valid word?

AUTOMATICS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

light machine gun
a pistol that will keep firing until the ammunition is gone or the trigger is released

Also: automatic rifle, machine rifle, automatic pistol.