I've seen barrel sleeves for ".36" -navy caliber guns so that cartridges are accurate...First off, how is the sleeve "fastened" inside the barrel? And is there a way to do it so as there is no 'separation' between the sleeve and the barrel? i.e I don't want to see it when photographing the end of the muzzle.
"You know what your problem is, it's that you haven't seen enough movies. All of life's riddles are answered in the movies." -Steve Martin