Gene... we did consider the headspace issue, and eliminated that by putting a piece of masking tape on case head and finding that the cartridge would not chamber with that .001" (or so) of extra thickness.
I wouldn't return the gun to Savage. They'll just keep it a few weeks and return it with a letter telling you either A) they couldn't find anything wrong or B) they fixed it, when in reality they didn't find anything wrong and are just telling you that...
It probably is the trigger. I'm assuming you took the bolt apart and inspected the firing pin and spring assembly (per videos linked).
On all of my Accutrigger, I pull the safety blade spring out from the top, and clip about 2 coils off it. This reduces the pressure needed to disengage that blade, and makes it easier to hold it back. That might solve your problem, once and for all. And it also makes the trigger that much lighter to pull.
Dan