Can't wait to see the finish product. 🙂
Dear Sir - spoiler alert.........it actually shot really small/well.
You don’t need different lots of belted brass to see headspace variance. I’ve had to cull 25% of both ADG and Peterson brass out of the same lots because they closed way to hard or not at all.
Just measure it. Putting shim stock in it without measuring is just guessing. You're better than that. C'mon.
Glad to see you all are making progress! I'm sure the rifle will be capable of some tight groups!