There is no set definition for small arms. The US Military defines small arms as having a bore of less than 20mm, and includes crew served support weapons. By that definition, the 15.5x115 FN BRG-15...
They are called Keratosis pilaris and are not dangerous in anyway. They are just a cosmetic blemish that 50% of people world wide have. (i have it too!) You can treat it by using amlactin lotion or...