What is This Tool?

Maybe a leather punch...It's hard to say, Sargent makes so many specialty tools of this sort..could be part of a kit with several attachments...

Could be for making ball chain connections...

Yes, it is a leather punch, can also be used to set rivets and grommets.

The subject punch is missing the (changeable for size and function) anvils and the adjustable depth gauge.

Having trouble with an image: search Sargent leather punch, there are quite a few out there for sale. These are a good tool, much better than the more common rotary ‘turret’ style punches.

Looking closer at OP image, there aren’t enough holes in the jaw for the leather punch I had a hunnerd years ago.

So, I need to amend my previous answer to ‘I Dunno’.

This compound plier was the basis for many specialty tools that Bernard/Sargent made.

Thanks for the help. From the catalog picture below, it does appear to be a leather punch(tube punch 181-8). However, it does not have provision for the adjustable gauge shown in the catalog picture.

You are both right however the OP item is a catalogue variation SAR - NIP -003 which is a nipple piercing tool, available in 1/16 , 1/8” , 1/4” and half inch

With different jaw shapes screwed into it, it could be useful for installing snaps, grommets, etc.

The one you have looks a lot like the ones used to number tag animal ears.

I have one just like it.

Also missing the punches.

I have always wondered what it was for, thanks!