Thank you, Bayedup7 ! A picture's worth 1000 words !
I think the TAC 408 bolt is .750 diameter, compared to the Rem .700" diameter.
There are arguments that the Rem should not be opened to the .590 Lapua
boltface. This would leave the same thin .055 edge rim thickness as a .750 bolt
with the .640 C-T/Gibbs boltface. That's what the picture is showing.
One of the arguments concerns strength of the locking lugs. At .590 boltface,
is the Rem strong enough ? Some say no. If the Rem strength is marginal,
how marginal are the TAC 408 locking lugs at .640 boltface ?
Now, I don't want to come across as picking on Stiller. Obviously there are
many TAC 408 rifles out there delivering excellent service.
My personal interest in all this is research for my next build.
( Comparing dimensions in different products is non-emotional, but sometimes
people think their toes are being stepped on. That is not my intent. )