Founder & ex secretary of Rivington Riflemen.
www.rivington-riflemen.uk
Thanks very much for all the input. And the level based puns! I totally get what's been said about the accuracy of smaller levels etc but I'd still like to give it a go. There is a flat spot on the stock at the back of the action so would use this as a level point. As for my door frames my house is 120 odd years old so I'm thinking they might not be true! Will have a look at those recommendations and see how I get on. Cheers all
One thing to try is, if you have a perfectly level worktop or bench then using a carpenters square lined up with the recoil pad screws can sometimes be an option.
Another is by using a piece of flat bar, say 1/8th or 1/4 inch by a foot or so, and balancing this on your known flat on the rifle. This allows you to use a slightly larger, and closer to accurate, level. You just extend the flat bar as a counter balance against the level.
Finally, when you know your rifle is level it's best to set the scope using a plumb line.
Not very scientific I know but it gets you close enough for the real world.