I'm not very knowledgeable about using cast bullets. After reading quite a bit of information on leading I was still unsure so I wrote to Lyman. Here is their response to my questions:
"There really is not a set velocity limit for a given type of alloy. It is a
combination of velocity and pressure that will determine which alloy is best
in a given load. Other factors such as barrel condition, groove diameter vs
bullet diameter, and lube used will also all factor in."
They don't give a lot of credence to the velocity and hardness knowledge I have been reading in regards to leading. It's velocity and pressure that determines which bullet to use and not bullet hardness, at least that's how I read it. Maybe I am not understanding what they are trying to say.
"There really is not a set velocity limit for a given type of alloy. It is a
combination of velocity and pressure that will determine which alloy is best
in a given load. Other factors such as barrel condition, groove diameter vs
bullet diameter, and lube used will also all factor in."
They don't give a lot of credence to the velocity and hardness knowledge I have been reading in regards to leading. It's velocity and pressure that determines which bullet to use and not bullet hardness, at least that's how I read it. Maybe I am not understanding what they are trying to say.