I think I should mention that I have read the manual carefully and that I wasn't HEAVILY lubing the gas piston, unless wiping it down with a patch wet with Break Free is heavily lubed. However I wasn't wiping it dry before shooting it. I'll take it to the range and give her another run with a dry piston. Also no barricade nearby when cases stayed in the chamber. The design also makes this rifle hard to put together wrong, no way that I can see (or have you found a way to put it together wrong the hard way?) Finally in section 4.2.6 of the manual it says to "lightly oil the gas piston and recoil spring" - I find it hard to believe that I oiled it so far beyond this point that I'm causing malfunctions (I do read manuals). Thanks to Redleg for taking an interest in this - I'll try to eliminate everything before I send it back.