I am about to begin my very first build. The only rifles I have ever fired have been AR15/M16's. I am very confident I can do this without any trouble, BUT, I am no Guru. I have a Bushmaster stripped lower w/ an A2 stock, I like the Hogue grip on my M4 Bushie, so I'll stick with that, but what's getting me is what kind of upper to go with. I really like the look of the Patriot Ordinance SPR 18" setup, and I'm curious to see if the gas piston is as good as the old fashioned gas tube operation.....so my questions are... Will a POF upper work just fine on my lower?....and If I decide on something else, should I worry about something not fitting quite right? Or are "mil-spec" parts all the same , no matter who made them?....If I don't go with the POF upper, I'm leaning towards a Rock River setup.........Thanks in advance guys.....

it'll all work.  But if you dont like that POF upper then i'll take it off ur hands free of charge

one of the nice things about the AR-15 system is its versatility ans swapability.. as long as the parts are made within spec they will work in just about any AR-15 (colt being the oddball here with its large ring/small ring lowers but those can be overcome with accuwedge etc..) It is just a matter of personal preference and finances.. for instance i am doing my 2nd personal AR-15 build 5th overall and i have never had problems with parts.. My current product is a basic midlength carbine that is being built on a RRA lower, the upper i would like to make RRA but its not a requirement. just remember, you do get what you pay for.. there is a fine line between saving money and getting junk.. My CAR stock is an example.. it is a POS that does not lock correctly. when I get the money i am replacing the tube with a milspec and going with the VOLTOR stock or similar..

Thanks guys....I was pretty sure I'd be ok, but you get all kinds of people telling me other wise. Usually the guy at my local gunstore.....but obviously, he wants to sell me a complete rifle, so he'll try to steer me away from a build. POF here I come......