After ruffing up the brass tube betweeen centers with 180 grit I use a q tip to apply a wax release inside each end of the tube then mix overnight cure t88 structural epoxy. Work time after I use a tapered insert tool to hold the tube and insert the tube about 1/4 inch into the wood blank, apply epoxy then insert about three quarters of an inch , rotate it and pull the wood off the tube reverse insert about 1/4 inch and use a pointed stick to apply epoxy to the tube , push and rotate the tube till it is even with the end of the wood, then equalize the brass tube between the slightly longer tube. Next day i chop saw the blanks to within a whisker of tubes at each end and usually he bushing will push the excess epoxy into the tubes,if not i use a tube inside scraper.
I do a first square to round turn prior to end sanding the wood concentric with the axis of the brass tube to the specified barrell length . To perform this feat i use my version of a sanding mill that i have installed on a small vertical drill press. back to the lathe for more precise turning knowing that every thing will fit correctly. I use apoxy during assembly knowing that i am creating an exact fit with adhesion only between the end sanded blank and the end of the metal engauging part. In the event that i must disassemble latter the inside of the tube releases because it has a wax release compound inside from the inserted hardware with the usual effort had i not have used glue. I do lots of 10 same kit builds.