I use Circa 1850 stripper I think it is...there are others. Spread on, steel wool to lift varnish and then wash off. Let dry and oil...the early guns seemed to be walnut even though sometimes you'd get outside/inside wood and there would be a lighter shade there. Doesn't look like beech to me...
Here's some info on types and dates... Savage Model 6A? - RimfireCentral.com Forums