Hey All,
I know that the times I have lined 22 barrels, I have used acraglas to secure the liners in the barrel. To hide the glue line, I have tinted the acraglas with lamp black. It works very well and there is no compatibility issues. Lamp black can be purchased from several on-line resources.
I thought I would add that the next time I am going to try using Loc-Tite thread compound to see how this works when lining a barrel. One good thing about Loc-Tite is that you can use heat to fix a problem if you make a mistake.