Pan lubing HT'd bullets

[Marlin Junky]

How many of you have checked bullet hardness before and after pan lubing? I pan lubed a batch of bullets cast of WW metal that were HT'd to BHN 21 and have been sitting around for a couple of months. I intentionally heated my lube a bit hotter that usual (just under 300F in the microwave) because I was lubing a bullet with lots of grooves. The resulting BHN 4 days after lubing was 6 BHN points less than before lubing; in other words BHN 15 vs. 21.

MJ

[copdills]

interesting , never tried that

[Morgan Astorbilt]

Did you check the hardness just before lubing? Lead and it's alloys are notorious for varying hardness over time. That's why I gave up trying to develop a Rockwell-Brinell Hardness conversion chart for them.
Morgan

[Ricochet]

Yeah, but 300°F is plenty hot enough to soften heat treated lead.

[454PB]

When you compare the weight of the heated lube to the weight of the boolits, I doubt you raised their temperature much.

Heat treated boolits do resoften, and several months might be enough to do it. I ran some experiments on this and was surprized how quickly quenched WW's started to resoften.

When I get really bored, I'm going to do another test and draw a graph of the hardening and resoftening curve.

[Marlin Junky]

Yeah, but 300°F is plenty hot enough to soften heat treated lead.

Right, but the point is, you don't need to apply the 300F for a half hour to an hour as I have read on this forum. Also, pan lubing with lube in the 225F to 250F range may be enough to decrease the bullet hardness significantly... perhaps 10% or more.

MJ

[Marlin Junky]

Did you check the hardness just before lubing?

Yup, a day before pan lubing and 4 days after.

MJ

[Ricochet]

Right, but the point is, you don't need to apply the 300F for a half hour to an hour as I have read on this forum. Also, pan lubing with lube in the 225F to 250F range may be enough to decrease the bullet hardness significantly... perhaps 10% or more.

MJI think you're right.