My question is about the Simson, Sauer, Merkel "post war" Suhl guns. Specifically, were they all built on the same frame size (12,16,20 ga.)

Also, I have read it posted on the internet that Merkel builds it's shotguns on it's double rifle frame and they are heat treated different than the others makes. Don't know if this heat treat info is true but it would be interesting to know when Merkel started this practice.