The pictures that I've seen and the gun I have, a 66 no dash, Have all been canted to the left. That is while in the drivers seat. Thay would mean you would have to loosen the barrel. I've read that the pitch, or number of threads per inch, they use for the barrel threads is 36 threads per inch. The different frames would employ different diameter threads but the pitch would be 36 threads per inch. So one complete revolution of the barrel would move the barrel in or out .0277" of an inch.( 1 divided by 36) If a barrel is canted by say 1 degree that would mean it was screwed in too much by .000077". (.0277" divided by 360 degrees). I've heard tell that some barrels are out by 5 degrees so that would put the barrel shoulder to frame gap at .00038". (5 times .000077")
So if you had to back the barrel out you would see a gap between the barrel shoulder and frame of that thickness ( very small). I would imagine you could use some sort of locktite to lock the barrel in place . That's also assuming the threads have not been stretched which is highly unlikely and the barrel shoulder or frame was not galled also not likely. One other thing this is based on a one piece barrel. I'm not familiar with the two piece construction employing a barrel and barrel shroud.