which is a lot of folks...

OK, in the 50s a sort of combination gun was imported into the US, maybe from Germany, anyway from Western Europe.

It was a Mauser actioned sporter, but in the forend was a semi hidden .22LR rifle action. Maybe semiauto, maybe single shot. Its barrel ended right at the forend tip.

So you don't want to choke up on the forend at the wrong time, as it could blow yer finger off.

And equally bad, it would appear to meet the definition of a short barrel rifle. The barrel was maybe 6" long, but it had a full shoulder stock. The fact a 24" or so barrel was above it would probably be irrelevant in the status.

I grew up seeing a picture of it in, I'm pretty sure, my Uncle Murray's 1955 "Gun Digest".

So what was it called? I'm not playing a trivia game. I legit don't remember.