Honestly, I wouldn't expect better than 1.25-1.5 MOA out of that rifle. It looks like your numbers are settling down with the LVR, I think you're on the right track bumping up the charge weight a little if you have room.
Some things you can do to help out your accuracy and consistency on lever actions-
Pull mag tube and forend. Drive out the mag tube stud and forend cap tenon. File/ sand the top sides of both until you have a snug slip fit in their dovetails.
With the mag tube still removed, set the forend in place on the barrel. If you have to push it into the correct position to fit the end cap on, identify where the pinch points are and relieve some wood. It should be an easy, but not loose fit.
Reassemble everything taking care to make sure the mag tube is centered. If you can, it can help to install a spacer either between the mag tube and mounting stud, or inside the mag tube cap to keep the mag tube from contacting the barrel.
The forend cap screws should be tight, but not so much that the cap is pinching the barrel. Around 20in/lb is plenty.
Rossi is bad for just jamming their sights and hangers into their dovetails. It puts a ton of stress into the barrel.
