Everyone that cleans an AR-15 has struggled with the task of cleaning the back of the bolt carrier. Some have tried bore brushes, solvents, dental picks, and even screwdrivers to break off this hardened deposit. These time consuming methods are hardly successful, and sometimes damaging.
There is a better way. It is a purpose designed tool called a 'bolt carrier carbon scraper', and it is extremely effective. The carbon scraper breaks up the carbon deposits, and makes their removal a simple task.
It is made from a steel bar stock fitted into a strong black "screw-driver" handle, and it is machined to fit closely into the bolt carrier. The "business" end of the scraper features four sharp cutting edges, and space for the broken up carbon to go. The very end fits into the back of the bolt carrier to provide perfect alignment.
This tool is well constructed, offers a nice tight fit, and works like a charm! Two or three twists is all it takes to remove years of carbon buildup.
ENSURE THAT THE FIREARM IS UNLOADED
Remove bolt carrier assembly
Remove firing pin retaining pin, firing pin, cam pin, and bolt from bolt carrier
Insert the carbon scraper into the bolt carrier as you would replace the bolt
Pressing lightly, twist the carbon scraper clockwise to break up carbon deposits on the inner surface of the bolt carrier
Clean carbon dust out of the bolt carrier with a cotton swab or cleaning patch
NOTE: The Bolt Carrier Carbon Scraper is not a metal cutting tool, it is only used to break up excess carbon buildup inside the bolt carrier. Care must be taken to ensure proper alignment with the bolt carrier. As with any reamer, turn only in the direction specified. Turning the Bolt Carrier Carbon Scraper counter-clockwise will dull this tool.