Got mine shortly after the sunset of the AWB. Inside, it is basically the AR-180 gas piston design that the Brits stole to make their L85/SA80.
Years later, I paid K&M to paint it green; change the charging handle, give me a new lighter trigger, remove the carry handle and give me rails on top, bottom, and one side; put some aesthetically pleasing cooling holes that also lightened it up, and a few other modernizing touches.
Great alternative to your every day AR-15. Long and accurate 21.5 barrel will ring all the speed out of your ammo while having a short, handy package.