Re: Nazi Mauser?
I'm not 100% sure, but I seem to recall reading somewhere that the Finns used a reversed swastika like that one, and the Nazis were allied to the Finns during the first part of WWII (mainly to act as a buffer state to the Soviets from the north) and that they supplied the Finns with some firearms early on in the war until the Finns got their Mosin refurb setups up to speed. So *could* it be something along that line? Maybe. Or maybe "Bubba" refinished the gun and thought he better put'em one of them thar Nassi-crosses back on it, so's everybody would know it was the bad guys gun? It certainly isn't like any German Nazi-era marking I've ever seen, that much I can say for sure.
Or maybe it *could* be a Nationalist Chinese mauser, maybe? What caliber is it?