Bought a new (to me) lower......problem solved! Feeds great, holds open on the Magpul mag, good to go! Lower is Norinco with an American LPK installed. I know, before you say it, big gamble with a Chinese lower, but the price was right and I have never had a problem with Norkie stuff, and hey, it fixed the problem! Thanks to everyone who threw in their 2 cents, great help from all. Going to throw all my extra parts together and sell the old receiver, maybe someone can use it, as a receiver or maybe a boat anchor!
Chris