Lilja's Response to the 6.5 Grendel barrels with non-standard neck and throat

[Grendanimal]

Any idea on the "time frame" that they used the out-of-spec reamers? What kind of fired case neck diameters would indicate the smaller dimension?

I suggest calling Lilja. I have always had good luck reaching someone (even Dan) on the phone, which, in my opinion, is an increasing rarity in the firearms industry.