Soak the outside of the barrel extension and the inside mating surface of the break with solvent and thoroughly clean them with a brass brush. It may take some time and effort.Got the muzzle break at the NE Ohio Bunch today. Went to install it and it was hard to push on. It’s a very tight fit and didn’t want to force it all the way flush with the end of the barrel. Removing it would have been impossible. Should they be so tight sliding on, what can I do to make it easier to install and remove? Larry