Hey HN, measure from the back of the cross-bolt to the back of the back center of cutout area so, it should measure 9" for threaded barrel and 8 7/8" for pinned. There will also be some variance between an early build stock vs. a late build stock as concerns threaded barrels as well as short collar threaded vs. long collar threaded.
Usually the issue is the fitment of the stock to the action and it doesn't want to sit down onto the cross-bolt. I have had success on fitting a stock to a different threaded barrel action, where the action is tight and doesn't want to fit all the way into the stock(like you mention), by placing the action into place as well as possible (using some kind of pad on the floor or workbench to cushion) drop the butt of the stock down onto the pad while applying pressure to the action toward the stock. If that doesn't work then you may actually need to cut some relief in the stock where ever it is hanging up(most commonly at the front lower ferrule and at the back center where the trigger group latch/spring goes down through.