Air cooled test at 20.9 -- will get harder? What about oven treating?

[ghh3rd]

My air cooled boolits from WW + 2% tin are around 12 BHN. I heard that water dropping them would result in about 22 BHN. I water dropped some tonight, and found that they are only about 20.9.

Do they harden much more over time? If so, how long before they reach their potenial? Should I wait to size, gas check and lube them?

Another question -- from what I gather, oven treating should result in higher BHN. At what temperature should the boolits be baked, and for how long. Are they carefully dropped into water one at a time, or just slid off a baking pan all together? About what BNH should I expect from oven treating?

Thanks

[AZ-Stew]

First, you might question why you need such hard boolits.

That question answered, here's the rest of the scoop...

Boolits that have been quenched after oven treating or having been water dropped will harden over time, taking 3 days to a week or more to reach maximum hardness. Personally, I prefer to oven temper mine so I get more consistent results. About 450F is a good heat treat temp. Use a thermometer to ensure the temperature, as oven thermostat markings are notoriously inaccurate. After an hour of the heat soak, take the pan full of boolits out of the oven and move them as quickly as possible to a water vessel and dump them in to quench. You might want to put a towel or other padding in the bottom of the water vessel for padding.

The final BHN will depend on the alloy and the temperature at which you heat treat them. The closer to melting temp the harder they will get, but at that temp you will also risk damaging the soft boolits. I've gotten BHN 30+ after three days from WW + a little tin, heat treated at about 440F for an hour.

I size mine and apply the gas checks before heat treating. This makes sizing easier and eliminates work softening when running them through the sizer. I run them through the sizer again after they've hardened for a few days to apply the lube using a larger size die.

Regards,

Stew

[MtGun44]

Nothing more to say.

[ghh3rd]

Now that I'm getting more decent 50yd groups with my RUger SBH .44 (thanks to advice I have received here) I thought I'd try some water dropped and oven treated just to see if I can tell any difference in accuracy in either direction. It's all part of the fun.

[NSP64]

What boolit are you casting for your SBH? And velocity ?

[ghh3rd]

What boolit are you casting for your SBH? And velocity ?
Right now I'm testing the Lee C430-310-RF 44, 21.5 gr W296 is moving it at 1348 fps.

[Bret4207]

This is where the "ultimate fit" I speak of come in. It's my term, it doesn't work for everyone. Ultimate fit is taking the boolit, at whatever hardness, and sizing to the area past practice shows to work best in your particular gun. Then you see what the loads you use do to the boolit- you try different seating depths, crimps, neck tension, Bhn. Each change you make affects the ultimate fit of the boolit in the throat and barrel. Each change should be recorded and observed. Changing to a different Bhn affects more than just "hardness", it affects pressure curve, powder burn, crimp pull, maybe the nose is a bit different...who knows all the tiny variables you change with a change in alloy or lube or brass.

Just realize Bhn alone isn't all you're changing.

[ghh3rd]

Good point Bret - thanks