To install standard handguards with a gas block rather than a sight post, what do you need to buy- a hand guard cap? What  parts are required to install a free float tube with a gas block? Thank you.

To change from standard handguard system, rifle or carbine, you need to have the gas block and the free float tube. The gas block cannot be up against the shoulder of the barrel where the handguard cap was. The gas block needs to be about 0.018 to 0.020 inches offset from the shoulder so that the gas ports will line up appropriately. Without this offset the gun may not want to run as a portion of the gas port that is blocked may reduce the gas volume available to the system. Charles.