[matthewt]

ui use foam earplugs as my ammo i squash them to about 4mm in diameter then in about 7 seconds there about 11mm in diameter

It's not about the speed, but getting the tip to impact consistently. It'd be hard to make expanding ammo if it could impact at any angle. Shot bags and balls of shot mixed in substrates like wax are exceptions, but they have their own issues.

I have to borrow the chrono again, but the dart-balls I made tonight seem to fly as fast and without hinderance. The flights are aerodynamically efficient once straight and level, offering little drag compared to the sinker. The only purpose is to make it travel with the tip forward.

I made better versions years ago when I was experimenting with spinning shot, but this served for a demo of the concept that I can make odd shapes hit end-on. Smaller flights are better. As are small flights on shafts (thought you have to glue the flights on). I just couldn't be bothered to make them myself to demonstrate the concept and the idea for hollowpoints hit me when I was in a sporting store by the dart section.

I don't want to actually make expanding ammunition unless I am fairly sure I'd not be breaking the law by doing so.