Moderator / Gold Bullet member
There are, I think, two methods. One is pressed into an oversize hole. I think the other is soldered but I don't know if it was silver soldered. Far as I know there have been successful repairs done by gunsmiths to mitigate the UGLY of the extension. It takes a little finese to do it without hurting the barrel. There have also been those who just replaced the barrel with a new one from Sarco when they had new barrels. I don't know if I'd go that far but it works.