I had a Bushmaster M-17S. Very accurate, piston driven. Mine was unusual in that it had enough threads to attach a Flash hider. They are NOT lefty friendly. Main problem was smoke would rise out of the ejection port and tear up my eye. I minimized this by using dry lube so there was no oil burning off.
In life, strive to take the high road....It offers a better field of fire.
"Robo is right" Fuzzball