Most bola stones I've seen have a narrow, incised, groove that is full grooved. The groove is not typically so wide. Of course, I'm no authority, just thinking off the top. What I have not seen, in either a bola stone, or net weight, is a groove that is only 3/4. One would expect some battering on the end(s) of a hammer, unless, perhaps, it was a soft material being hammered. Maybe it was intended as a small weight, but the groove was not finished. I have found one grooved weight where that was the case....
it is nice thats for sure,i wish i could see more of the bola stones,as i think it is a cool weapon.not saying thats what you have though.thanks for sharing.i heard they would wrap the stones in leather to make a bola though,yours do not look like it was done.
Not that I know, but from what I'm seeing online of a bola the stones are secured in a sack made of gut and with that there isn't any need for a groove in the stone to keep the bola all together when swinging it around. Seems to me a stone swung with just a single rope of some kind wouldn't hold together with the G force's of swinging the bola stones around and around at high speed.