Here is what I did . I took my Smoktec Telescope and aded msome copper sleeves . I did this for two reasons . First , in shorty mode with a AGA-t on it there was a big gap and step down due to the cone on the end . That step down felt awkward , it missaligned in the hand and was hard to fire due to the bad alignment . Second was for looks , it just looks better now .
The bottom sleeve is pressed on . To do this I took the copper pipe and sanded down the inner diameter until it would almost fit if pressed by hand . I lubed it up with dish soap and used a big C-clamp and pressed it on . I made sure to go just far enough that my second section of copper would sit atop the ledge created and just reach the top of the cone . Then I took the second section and glued thin strips of heavy foam on the inside so that when pushed over the top it would fit snug .