This is it! nothing better (except for one scenario) - Arisaka Defense Combo Optic Levelers

I'm not sure where I bought mine from, I can't find it in my OP order history but I would buy it again in a heartbeat. Less than a heartbeat.

There is no faster, easier way to level a scope. I have just about everything another well know company makes for leveling scopes with all sorts of bubble levels that clamp on barrel and sit on rails and and levels that sit on the elevation cap of the scope you can throw it all away. That stuff is clumsy and honestly not very accurate no matter how careful you are with it.

Mount you rings on the rifle, mount your scope loosely in the rings (loose enough you can move it and tight enough that it stays when moved) and jam the grooved plate and one of the wedges between the rail on the rifle and the flat part on the bottom of the scope under the elevation dial. Make the flat of the scope square with the wedge and you're done. Works on both traditional rings and cantilever mounts.

About the only place this hasn't worked for me is my Remington 700 because there is nothing under the flat bottom of the scope. It has two short pieces of rail, one in front and one behind that action. I expect you'll have a similar challenge with many of the bolt actions on the market. In that case you might have to hate life and go back to the bubble levels. But anything with a continuous rail or flat surface under the scope, this tool will have you level in about 30 seconds.