Hate to give it away so soon but these are lead weights used for fish scaling. Slamming the top part into the fishes head the holes which are hooks on the bottom hold the fish in place while you pull down and back to remove the fishes scales.
It's a team sport. At the time pretty much exclusively American. A few games are now played in other countries, including over here in the UK, but this piece of equipment has been obsolete for decades.