CREATE TABLE table_17836 ("Colt model no." TEXT, "Name" TEXT, "Stock" TEXT, "Fire control" TEXT, "Rear sight" TEXT, "Forward assist" TEXT, "Barrel length" TEXT, "Barrel profile" TEXT, "Barrel twist" TEXT, "Hand guards" TEXT, "Bayonet Lug" TEXT, "Muzzle device" TEXT)

What hand guard system is used with a gas piston commando?
SELECT "Hand guards" FROM table_17836 WHERE "Name" = 'Gas Piston Commando'
SELECT "Hand guards" FROM "table_17836" WHERE "Name" = 'Gas Piston Commando'