Is the Sabre Defense upper a 1 in 7, 1 in 8, or 1 in 9, that you are contemplating?
It's the 1 in 8. It's the only one that had a 20 inch barrel. There was a 1 in 7, but it was an 18 inch barrel.
Since my maximum engagement envelope is out to 600 meters I figured a 20 inch barrel would be ideal, even if it's a 1 in 8 twist.
If you buy a stripped lower, it's not specific to either carbine or rifle stock. If you buy a completed lower, it will come with one or the other.
I'll likely purchase a completed lower that is specific to the rifle stock as well as the completed Sabre Defense upper.
Heck I might just buy the complete rifle from Sabre Defense and then purchase the optics, scope mounts, and stock ergonomics separately.