Weird AR Problem

[Joker31D]

Its a fixed thing now but for a while I was shooting me AR in 6.5 Grendel and it was showing pressure signs (Popped primers, swipes etc) and I couldnt figure it out. It was throwing rounds all over, 5" group at 100m

I had built 3-400 of them in the past, some while working at a company that sells AR's with their name on them, about 50-100 in the Military and I have been to Colt Armorer Training and am even a trainer so I couldnt figure it out for the life of me. I checked headspace, had the barrel maker check it out, had another armorer check it out on base, nobody could figure it out. The weirdest thing was what I figured out, The damn charging handle wasnt allowing the bolt to go completely into battery, The channel was cut short and it didnt allow the carrier to go forward enough. I was looking at the parts as I put them in to soak in the Ultrasonic before I sent them off to have them X-ray'd for cracks and there was soot build up on the end of the charging handle I didnt see previously. damndest thing I have ever seen. I have been messing with AR's since only colt made them and had never seen that before. Its not like the charging handle was a chinese knock off, it was an expensive charging handle, I dont want to say which company made it until I have them check it out but I'm pretty sure lots of people use them on this board. I just thought I'd put it up here in case anyone has a phantom problem like that. I went so far as to have a company schedule time to xray my stuff because I was so certain it was something complicated. My barrel is a Satern that was custom profiled for me and has cut rifling(5R), if it didnt I would have just grabbed another barrel off the shelf.