carbine gas on a 20" wtf--? .130 gas hole? --i just don't know what to say.
i never heard of moors machine.
if i had to guess i would say it sounds like somebody raided the scrap parts bin to build this one.
that barrel sounds like a disaster. it probably has out of spec head-space because of an improperly installed barrel extension & pin.
probably a oversize 223 chamber too.
you sure this ain't a hess kit gun?
very old m-16s we had were very loose in the upper to lower fit. they worked fine though.
later ones-- they got tighter in the fit thanks to CNC mills.
more than likely the upper and lower are from the reject bin though i can't say without eyeballing them. when you get a lot or run-out you get that loose fit.