... I have been looking at building an AR. From what I have read, the lower has little impact on the reliability and accuracy of the weapon, if decent parts are used. Accuracy and Reliability are influenced by the bolt carrier group and the barrel and chamber. Is this information accurate?
If so, is it possible to build an AR, with a basic lower and a basic upper with a Bravo Company/Daniels bolt carrier and barrel that would rival the reliability and accuracy of top of the line weapons, such as Colt, DD, or BCM? I looked at just buying an upper from one of those companies, but they are expensive. Would a PSA upper with a updated bolt carrier group give good results, or are their other parts which would also need to be changed?
Bottom line, is it possible to build a very accurate and reliable AR rivaling at top tier AR for a lot less money?
I would say you can save some money on a top tier AR by doing what you suggest. Whether you can save a lot of money yet retain high quality depends on your components selection.
I recently bought a PSA barreled upper receiver, added a BCM BCG (as PSA was out of stock) and put the upper on a stripped ArmaLite lower built up with an ArmaLite LPK and PSA receiver extension/H buffer/CTR stock.
Over the last couple years I also bought a BCM upper and Daniel Defense upper then mounted them on good stripped lowers (S&W and JD Machine Tech/Valkyrie) built up with DD LPKs and BCM receiver extensions/H buffers/CTRs.
All three happen to be midlength gas and all perform roughly the same although I have to give a slight nod to the DD upper. All are reliable and should perform the same as a complete factory DD or BCM.