Things You'll Need
Instructions
Turn on the safety. You always want to secure the safety when changing gun parts. Remove all ammunition from the MP40.
Use a wrench to remove the muzzle nut. Place the muzzle nut in a safe location so that you can reattach it later.
Unscrew the barrel. Replace it with a new barrel.
Use a wrench to secure the muzzle nut back in location. Replace your ammunition and release the safety once you wish to use the MP40.