DT,
SAAMI blueprints recommend .4426" ID for chamber diameter at the web join. Grendel ammo should be .4410" OD at the web join. So the designers consider .0016" of expansion to be safe and reasonable. Your expansion in the Lilja is two to three times SAAMI ammunition.
I don't know what other discussions you've had with Lilja but this one is pretty straight forward.
SAAMI blueprints recommend .4426" ID for chamber diameter at the web join. Grendel ammo should be .4410" OD at the web join. So the designers consider .0016" of expansion to be safe and reasonable. Your expansion in the Lilja is two to three times SAAMI ammunition.
I don't know what other discussions you've had with Lilja but this one is pretty straight forward.

