I have done that before, to replace the old fugly receiver on an earlier build. I ended up using a small butane torch to soften the epoxy and then dug it out with a pick. Other than that I hope to never have to take it apart.
Thanks for the comments.
Was just looking at FB Radom's website, and they give the bbl measurements of the newest Beryl M762 assault rifle as 419mm, which is 16.4961 inch. So mine is much closer to a new real Beryl M762 than I thought, except furniture, which I used the older style, and caliber, M762 is 7.62x39 instead of 5.56 nato. I think this is what some refer to as the "commando", only this one looks like it uses the regular length gas tube instead of the mini beryl tube. » Beryl M762 Anyhow, whatever it gets called, it was a fun and very involved build, and it shoots really sweet. Pic of a M762