I think it was Bruisemaster just recently said he uses hot glue… and heats up the glue end of the barrel to give you more time to twirl the barrel in the T piece to ensure an air tight seal… I am going to try this next time myself… I have alot of sealed barrels (comes with T piece pre glued) … but next time I need to glue, I will try hot glue.
The main attraction for me, is if you want to separate the T piece from the barrel at a later time… you just have to heat the T piece/barrel join and the glue will liquify again… so you can use the T piece and the barrel on other projects…
Just because I like the sound of my own typing… when gluing a barrel/T piece whatever glue you use, test fit the barrel into the T piece and make a mark or put tape to show when the barrel is totally inserted in the T piece, then put the glue on the barrel (not in the T piece) where it will be going into the T piece at least 5mm from the end (so the glue cant ooze past the end of the barrel and block it)… then push the barrel into the T piece and twirl (not twerk Rattler) a little so you know it is fully ‘home’ then leave it to set. Hot glue would only need until it cools.
Like I say, I haven’t tried it… but I will try one day