ok im looking at getting/making a machine gun grade upper (shtf) and im thinking about the POF uppers. reason being is purely for the quality of the barrel. im not a huge fan of the piston systems nor the short sight radius of the POF stuff. is there another barrel maker out there that offers a similar quality barrel in a rifle length. my other option is a heavy barrel chrome lined rifle length from RRA. and it is going to be used on a select fire M16. this plan involves using it as a LMG in shtf type thing so weight isnt as much of an issue as it will be filling the role similar to a M249SAW. im not getting a belt fed atm due solely to the versatility of the M16 in use of multiple uppers which can be swapped out same as a MG barrel for cooling. so im thinking i can just buy 3-4 DI chrome lined barrels and uppers with BCG for the price of ONE POF. but all i really need is one extra upper as im upgrading all of my other uppers to FA bolt carriers. so the question im undecided on is just one REALLLLLLY good upper missing the extra sight radius or a cheaper DI with a proper rifle sight radius. or is there another brand im missing to look at??