Grendel Upper: Oversized or standard barrel extension tunnel

[montana]

If you ever want to rebarrel, you might not get the bedded barrel out.

I have never had a problem removing any bedded barrel from an upper..

Many use a wooden dowel and tap it out but I found this to be the easiest method..https://www.youtube.com/watch?v=abxYM6ZQK_E&t=3s
I never used this for thermal fit barrels as a quick heat with MAP gas releases it quite easy..