Question: Which Barrel twist has a Stock of Canadian 3rd Generation and a Hand guards of Short Ribbed?
SQL: SELECT "Barrel twist" FROM "2-12834315-8" WHERE "Stock" = 'Canadian 3rd Generation' AND "Hand guards" = 'Short Ribbed';

Question: Which Hand guards has a Barrel profile of A2 and a Rear sight of Weaver?
SQL: SELECT "Hand guards" FROM "2-12834315-8" WHERE "Barrel profile" = 'A2' AND "Rear sight" = 'Weaver';