Mixed some lead today ?

[melloairman]

Started with a full Lee 4-20 pot full of 5 bhn lead The most I think I have gotten in or out of it is 19 pounds . Been trying different bhn rates in a mold . The mold was filling good at 9 and 12 bhn range lead . Bhn tested on a Cabin Tree . The 5 bhn would not fill the mold as I needed . Pulled 10 pounds of lead out of it and filled it back with 14 bhn . Mold filled as it should and yielded 1.2 grain heavier bullet than the 12 bhn lead . I will wait to test for a week or so and again in about 30 days . Any thoughts on what I might have ? Marvin

[454PB]

Pure lead (5 BHN) needs higher temperatures to cast well, because it has a higher melt temperature than lead that is alloyed with tin and/or antimony. Also, the addition of tin improves fluidity and produces a better boolit. You didn't say what your 14 BHN alloy was, but obviously it contained some tin and antimony, resulting in a lighter and harder boolit that also produced a better casting.

[melloairman]

Pure lead (5 BHN) needs higher temperatures to cast well, because it has a higher melt temperature than lead that is alloyed with tin and/or antimony. Also, the addition of tin improves fluidity and produces a better boolit. You didn't say what your 14 BHN alloy was, but obviously it contained some tin and antimony, resulting in a lighter and harder boolit that also produced a better casting.

I did state that it was range lead . And I did state that the bullets were heavier than the 12 bhn bullets not lighter . I tested the bullets today and came up with a 45 on the dial . Will see what happens as time goes by .Marvin

[454PB]

OK....range scrap. It's unusual to see it that hard.

My point was that a slug poured with pure lead will always be heavier and softer than one poured from an alloy containing antimony and tin. If it isn't, there's something else going on.

[melloairman]

Day 6 and it tested at 55 .Marvin

[454PB]

55 bhn?

[melloairman]

55 bhn?

No 55 on the cabin tree dial = 9 bhn.

[melloairman]

Day 9 still at 55 on the dial .Marvin

[montana_charlie]

If it isn't, there's something else going on.

With the alloy, he finally got the cavity filled.

[melloairman]

Day 12 and at 60 on the dial . Hope it does not go over 75 .Marvin

[melloairman]

Day 17 now at 64 on the dial .Marvin

[454PB]

Those numbers would mean more if they were converted to BHN.....we don't all use the Cabine Tree tester.

[melloairman]

Those numbers would mean more if they were converted to BHN.....we don't all use the Cabine Tree tester.

64 = 9.5 Will try and remember that . If I forget there is a sticky with a chart on it .Marvin

[melloairman]

Day 24 tested 3 samples as normal and came up with 57 on the dial for 9 bhn. Marvin

[petroid]

I think that makes sense. You pulled out about half of the 5 BHN alloy and replaced it with 14 BHN alloy. Your resultant alloy comes in at about 9 BHN and drops slightly heavier than the 12 BHN alloy, which it should because it has more pure lead in it. Your 5 BHN lead is pretty much pure lead. Your 12 BHN range scrap could be anything but it sounds like its pretty close to 50/50 pure/WW. What are you casting for?

[WALLNUTT]

I saw no mention of "range scrap" in the original post.

[petroid]

Been trying different bhn rates in a mold . The mold was filling good at 9 and 12 bhn range lead .

I assumed this was referring to range pickup lead. AKA "range scrap". Correct me if I am wrong

[melloairman]

I assumed this was referring to range pickup lead. AKA "range scrap". Correct me if I am wrong

I re read my original post and see that I was not as clear as I should have been . Yes the 14 bhn was range lead . I will test this out for at least 30 days . I am casting for a 201 and a Recluse air rifle . Both are 9 mm Korean models. But shoot .358 or .3585 bullets up to 12 bhn and then lose power and accuracy past that point . Marvin

[454PB]

You should not see any more change. I've done long term hardness testing on heat treated boolits, and they do continue to harden for several months, but I assume you air cooled and no additional treatment if you're looking to control hardness.

What I don't get is why hardness over 12 BHN causes lost power and accuracy. I know nothing about casting for air rifles, but I do cast for 9mm.

[melloairman]

You should not see any more change. I've done long term hardness testing on heat treated boolits, and they do continue to harden for several months, but I assume you air cooled and no additional treatment if you're looking to control hardness.

What I don't get is why hardness over 12 BHN causes lost power and accuracy. I know nothing about casting for air rifles, but I do cast for 9mm.

Yes air cooled . But I have had changes at and beyond 30 days with air cooled range lead bullets . As far as the power lose and accuracy issue goes . I have heard that it can take place with PB as well . I do not claim to know all the facts as to why . But the barrels are wide land , narrow shallow grooved . You have to run a tight fit to start with for accuracy . But to tight and shearing takes place since the lead has no were else to go but backwards with a low bhn . To hard and the grooves can not fill and hold as they need to . And with a chamber pressure of 2000-3100 psi not 30,000 psi things happen as well . I have replaced the barrel on a couple of my Korean rifles with TJ barrel liners that are made for PB with a more conventional land groove and been able to shoot 22 bhn bullets with no lose of power or accuracy .Marvin