Had one that made similar shape years ago from England worst slugs ever nothing would group period. Gave up donated it. Not sure if this ones the same UK manufacturer mines was like a decade Or longer ago. Waste of time and money. Mines was in 22.
I wouldn't mind finding one that mimics the discontinued fantastic UK made ELEY MAGNUM BULLETHEADS though. 100+ yard tack drivers straight from their huge puck sized tins.
I have been trying to find a 30 cal pellet mold made here in the US but they are ether out of stock with no info when they will come back into stock. or it is 4 to 8 weeks before you can get one. So I am going to try and make my own. Will be interesting to see if I can do it.