Several years ago, someone came up with the notion of a heavy .177 mold for air rifle pellets. This heavy pellet was to hit like the hammer of Thor and carry a long distance. It was billed just short of being suitable for cape buffalo. This was contrary to what I wanted in a pellet. If it had a parachute to stop it at my property line, I'd been first in line for it. I didn't order one, but someone ordered one for me. The pellets keyholed. The designer of the mold said his design was changed and results were as he would expect. Someone in South America I think it was, reported good results if you shot them backwards. I did not find that to be true and penetration was dismal. Actually I use my pellet rifles for pest birds and penetration not really a factor. It is an aluminum mold and as is useless. Was wondering if any of the machinist types in here could perhaps mill it down to make a lighter pellet that might work?