I've never had my paws on a Remmy 798 - but have you checked for a third bottom screw just forward of the triggerguard, under the floopplate ?
My CZ550 Safari had a 2nd recoil lug in the mid-point of it's barrel channel, but it wasn't physically tied to the barreled action in any way - it was linked to the forward TG/action screw via an inletted link.
Another thing to try:
If you have access to a chest-type freezer (or it's REALLY cold outside), freeze the entire rifle for a few hours to slightly shrink the metal in relation to the wood, and give the underside of the barrel just ahead of the forend tip a solid upward thwack while the stock is securely held DOWN.
.