9mm reloading

[relliott]

I'm not sure why driving them faster would cause keyholing; a higher rotational speed should make them more stable, if anything.

If the bullets are undersized relative to the bore diameter they will be more or less shearing off in the rifling as they pass through the barrel. This effect will be exacerbated with increased velocity, or if you're using very fast burning powders (like Bullseye).

 

[raymond3080]

Thanks for all the replies everyone!