When building your next AR or AK firearm, you’ll arrive to the upper parts and may get overwhelmed with the overall number of parts that make up the upper assembly as well as the different options available to you. From the barrel itself to the charging handle, handguards, gas blocks, muzzle devices, complete uppers and everything in between. Click-Click-Boom has you covered with all of the biggest brands as well as parts for those on a budget.