I would think it's a leather "Billy Club".
Not of a military nature but an interesting item.
All the best
In the US I think they are known as a 'blackjack' ???
" When you're chewing on life's gristle, don't grumble, give a whistle "
Round abouts our way it's often reffered to as a 'paying out stick' or a 'persuader'......
'I do not think we can hope for any better thing now.
We shall stick it out to the end, but we are getting weaker of course, and the end cannot be far.
It seems a pity, but I do not think I can write more. R. SCOTT.
Last Entry - For God's sake look after our people.'
In memory of Capt. Robert Falcon Scott, Edward Wilson, Henry Bowers, Lawrence Oates and Edgar Evans. South Pole Expedition, 30th March 1912.
It's also known as a "bartender's friend"....A leather covered chunk of Lead on the end of a Spring(which is Also leather covered)I had 2 of these "drunk fight stoppers" behind my bar for years....and, boy do they do the trick(That, and they sure do break ice cube chunks nicely! Loudmouths in the bar sure take notice when you crack ice with them...)....You do, however, have to be Extremely Careful in the location of the administered "quiet down,you!" as with these types, it is Very easy to break the Skull, and then You go to Prison.... It's why the Police and the Military eventually phased them out and went with the "flat sap" or "Denver Sap" as they were known. They were basically the same concept, but were flatter and wider than these blackjacks like yours. Being spread out abit wider, they tended to Not fracture the head they were thumping on. The safest spot to aim for, by the way, is behind the ear...(just so you know..) Nowadays, of course, you have your tazers, pepper sprays, etc, but back in the Day, these pocket punchers were quite common. In fact, I just saw one in a resale shop near here(75 bucks-and no, I didn't buy it)-an enormous brute of a blackjack that made me swallow hard imagining the "tender bits" it had administered over the years. Another note of caution-these are Not Legal to own or carry in many locations, so you had best Check your local Laws!
"Much that once was, is lost. For none now live who remember it."
^ Great info Wagriff, very interesting stuff there!