Coming from personal experience, testors paint can wear off very easily if the surface is not sanded as well as any other paint I have used on plastics.
That Tiberius Tac 8 is allowed on every field I ever went to. It shoots 68 cal paint semi-automatically. No problem. And that XM8 is actually a Smart Parts SP8. And a 24 Inch barrel, wow that is long.
So to remove the AR, you have to keep poking it until it comes out the back? Why; is something holding it in place that you can't take off? Could you drill it out through the back?