Is the rifle 100% stock? Remmy almost always cuts their chambers LONG, to CYA on these types of things. At mag-length I still can't get my bullets as close to the lands as I would like (the 178 AMAX really likes to be 0.010 from the lands) I can get them to about 0,070 and keep it to the AI mag length.

Your chamber measurements are pretty close to what most find in stock Remmy chambers. I shoot a different bullet, so we can't compare apples to apples, but I'm at 2.954 COAL to be at the lands (measured with proper tools). Given the different bullet shape 2.950 sounds perfectly reasonable to me. Though the hornady tool to get a good measurement isn't terribly expensive and would probably be a good investment.

Go back to the low end and try a different batch of primers, powder and bullets and see what you get. It is possible something there was out of spec.