Well finnally had a chance to run the M5.Didn't do $hit to it just slapped the upper on lower and went.Started with some 150 mil-surp [indian I think] .Didn't want to feed from brand new Pmag.So I went with PPU 168 gr..Started with single round.let CH fly,feed ,shot and locked back.Loaded mag and it would strip round but BCG would not go into complete battery.About 3/8 shy of lockup.Kept fukin with it and no wroky <dontknow> .Removed mag,squired a little weapon shield into carrier and put alittle rifle grease on the lugs.Pulled back would not close completely.Repeated,then the bitch lock shut like Ft.Knox >:( .It's fukin 90 and humid I had to go.Call our guy in Cali told him what was up.He said I had to mortor the motherfuker :eek: .So I did,3rd strike she opened up :yup: .Stiff to retract.Took it apart CH was dry [TacOps] lubed it and upper.Cleaned the chamber,swiped the barrel.Took apart the Nickle boron BCG and wiped with CLP.Reassemble BCG put a little grease on the outer edges of the bolt and pushed in sole and saw it was VERY tight going into the chamber.Teeth on bolt to edges og chamber.Aero was suppose to headspace this BC and I made a point of telling them I wanted it ready to go.Upon inspection it didn't looked like it was fired :ugone2far: .I changed the extention tube and spring with an Armalite carbine tube from my brother from another mother.Replaced the spring with an Armalite E1095 spring.You can see by the pic that the Armalite setup is longer.Been strokin the CH and BC slams home,worky mo better.Go in the backyard tommorrow the check feed and ejection.For the couple of times I got it to shoot it's a mild shooter. ^-^