Great advice from everyone. Thank you all for the positive feedback once again. Results from yesterday on the range indicate that ammo varies WILDLY. Neither of my AR's like the PMC 62gr green tip stuff. Flyers all over the place even with a scope, so I'm glad I did not buy 1000 rds of that. Some surplus 55gr stuff I had actually worked well, but it's intersting to see the differences from one brand to another, even with the same bullet weight.
With S&B 55gr .223 off a basic rest I was able to get irons zeroed and my red dot zeroed at 100m. With irons I was getting on target and around 3 inch groups, the dot (1x23 Bushnell) got most of my hits within a 2" circle at 100m. With the dot at 50m off hand and kneeling, shooting faster shots all in the A zone of an IPSC target, so practical rifle matches might not be as shameful as before.