What??? 3 different bhn on 3 bullets out of the same pot

[tygar]

OK guys I'm confused.

I wanted to check some lead I got a while back from the recycle place.

It tested reasonable soft prior to smelting, 8.7!

It was basically flashing type that was 4 to 8" when flat.

I melted it & fluxed twice, with lube & wood. I added aprox. 4ozs of pewter to about 9#s.

I wanted to see how it filled & if needed would add more, but it was OK.

I cast 20-30 of each & let air cool.

I checked at 48 hrs & this is what I got.

So how can I get a 9.2 on a 255gr .452, 10.4 on a 165gr .308 & 13.4 on a 325gr .458.

All cast out of the same pot, at the same time & all air cooled.

BHN test on the Lee. Checked it 2 times & both came in within .3. The above is the avg.

9.2 - 13.4 is just wrong. Whats up with this?

Just have to hear what the experts have to say.

Thanks
Tom

[osteodoc08]

I know with my Saeco tester it must be flat. I use a FP handgun boolit to test and they are consistently around 12 BHN for air cooled COWW with some tin added. About what I expect. It is consistent and accurate.

So perhaps the bullet shape is what gives you the erroneous readings? I'm not familiar with th Lee tester.

[tygar]

All bullets were flat nose & tested on the meplat flat.

[swheeler]

OK guys I'm confused.

I wanted to check some lead I got a while back from the recycle place.

It tested reasonable soft prior to smelting, 8.7!

It was basically flashing type that was 4 to 8" when flat.

I melted it & fluxed twice, with lube & wood. I added aprox. 4ozs of pewter to about 9#s.

I wanted to see how it filled & if needed would add more, but it was OK.

I cast 20-30 of each & let air cool.

I checked at 48 hrs & this is what I got.So how can I get a 9.2 on a 255gr .452, 10.4 on a 165gr .308 & 13.4 on a 325gr .458.

All cast out of the same pot, at the same time & all air cooled.

BHN test on the Lee. Checked it 2 times & both came in within .3. The above is the avg.

9.2 - 13.4 is just wrong. Whats up with this?

Just have to hear what the experts have to say.

Thanks
Tom

let them age 2 weeks and check

[williamwaco]

Two things.

If you check 5 of the same bullet, you will get at least three different readings.

All the bullets are significantly different sizes and shapes.
They will all have different cooling rates.

Cooling rate affects hardness.

[xacex]

A heat treat on the batch, and a wait for the alloy to settle out for a week to two weeks should do the trick. If you do not want heat treated boolits follow Wheelers suggestion of just waiting it out for the alloy to balance out. But, I am no expert.

[Mike W1]

Seems like my LBT rig mentioned not getting too close to the edges of the testing area. Don't remember offhand just how close but that could factor into I guess being it was mentioned somewhere.

[303Guy]

I've had different hardness (or softness) on the same boolit in bands along its length. That was due to the way the alloy was filling the mold, forming a central lump which then collapses then starts over again.

[John Boy]

All cast out of the same pot, at the same time & all air cooled.
Not mentioned is the melt temperature for each and the pour time for each.
Also the variation range of the hardness's is abnormal ... like stated - let them age and test periodically

[captaint]

I wouldn't lose any sleep over boolits from 9 to 13 bhn. I mean, it's not like one is 9 and the other is 20.... Besides boolits are tough to check for hardness anyway. I like to do ingots and forget about it. My own experience tells me it doesn't make a lot of diff anyway, at least for pistol boolits. If I needed considerably harder rifle boolits, I would make sure they were harder - not in the 13 neighborhood. Just my .02. Mike

[Dusty Bannister]

I try to avoid the variations introduced with bullet sizes and pouring rates by using the same mold for all alloy samples. I like the Lee 500 RF with the length and wide meplat. Large casting heats up the mold quick and well filled samples seem easy to make. But I also wipe the base and nose of the casting across a file to remove any small bumps before testing the sample in the Cabin Tree tester. This sample prep is also recommended by LBT but I do not know about others.

As an additional thought, if you are testing the sample by filing a flat on the side of the bullet, are you applying the pressure on the driving band, or between the driving bands where the sample is not supported? I do not know if that would make any difference on a larger caliber pistol bullet but on the smaller rifle bullets, it "might" allow the bullet to flex or bend, and go unnoticed.
Dusty

[tygar]

OK some more input.

From Mike on not doing it on the edge. Dam, I do close to the edge on bigger bullets so I have the flat to hold the lee scope on. My hands shake trying to hold that dam thing so I can see it clearly.

I know about the different sizes maybe affecting the curing time hardness but one of the interesting issues is that a 255gr was softest at 9, the 165gr, the smallest was in the middle at 10.4 & the largest was the hardest at 13.4.

Shouldn't it be largest-softest, smallest-hardest??

Also, the ingots that these bullets were cast from are 11.8. That is after over 3 wks.
And, the primary lead they were made from was 8.7 before smelting, I had added a lead pot type thing I cut up & did not test but it bent easy like the strips.

As for the hardness of the rifle bullets, this was mainly for a test of the mix & break in of the RD 165 mold. They were going to be shot, if at all, at low velocity, just for grins.

The 5 BHN spread & the way the hardness is backwards with the largest the hardest (if I understand how it should work) is confusing/interesting.
Thanks

[Calamity Jake]

You need a minimum 1/4" diameter FLAT to check hardness on with the test indent close to the center NOT on the edge.
The tool and how you measure the indent plays a big part in getting an accurate reading.
The lee tester as I understand it requires that you apply a given amount of pressure for a given amount of time then
measure the indent size and compare on a chart, if you don't have a way to measure and repeat the pressure/time applied with
each test then your testing is flawed. Everything needs to be repeatable.

Also the biggest boolit in your test requires the longest cool time meaning it will check softer than the medium or smallest.

As been stated above let them age for minium 10 days then test again.