What is this used for?

Hi I got this from an auction with some good tools. Wondering if anyone can tell me what it’s used for? Thanks in advance!

Those look like pipe vises or perhaps gunsmith’s barrel vises.

I’d second that looks a bit like a gun smith vise for gun barrels. might be missing a piece or cork or rubber for the insides.

I’ve seen newer ones that look similar to that - made to be clinched to the barrel first - then chucked into a bench vise to hold it still.