Question: How can I clean out the gas port on my M1 carbine?
Answer: In order to clean the gas port, you’ll first need to remove the gas piston nut. This nut is accessible on the rear of gas piston housing under the barrel. You’ll need a special wrench to remove the nut which, by the way, is often staked in place.
Under normal conditions, the nut was never removed for everyday cleaning. Once the nut has been removed, the piston can be withdrawn from the housing. The gas port can then be cleaned with a standard #50 (.070î diameter) drill.
Hold and turn the drill bit by hand and be careful to avoid contact with the inside of the bore. For goodness sake, don’t mount the bit in a drill!