JonB
Halcyon member
I know some of you will recommend the usual "it don't matter, just shoot'm" and that's fine ...But I am just OCD enough to wonder why.
This turned out to be longer than I planned, there are a couple questions at the end, if you chose to read through this whole post.
I measure hardness of my batches of bullets quite often, and I regularly get "expected" results.
But, once in a while I get a batch of bullets that age hardens more than expected. I usually don't give it much thought and just save that batch of harder bullets for a different/increased load. I do keep a chronological log of each casting session, and try to enter BHN readings in there.
In the last few weeks, I've been loading ammo like crazy. (500) 38 super, (2000+) 45 acp, (2000+) 41 mag.
>One batch of bullets were cast (air-dropped) in Jan 2018 from 40% COWW, 60% soft.
BHN was 8 @ 1 hour (1-5-2018)
BHN was 11 @ 6 weeks (2-20-2018)
BHN was 14 @ 25 months (2-19-2020)
Another batch of bullets were cast (air-dropped) with straight COWW.
BHN was 10 @ 1 hour (9-29-2016)
BHN was 18 @ 4 years (2-22-2020)
...I wish I had another one or two measurements from 2016
When I looked into my casting Log, I seen that I had used my Auto-Battery term alloy prior to both of those casting sessions I mention above, where I got hardness anomalies. The story of the Auto-Battery term alloy is as follows. I got three 5-gal buckets of battery cables ends from a auto-recycler when I first started casting, there was a few strange items in the buckets which by look and feel, I figured they were soft lead...one item was reportedly a weight that Chrysler put in some steering systems? Anyway, I got a yield of about 200 lbs of ingots from those buckets. I smelt in 40 to 50 lbs batches. So there was 5 batches of ingots, that could have been different...and of course Newbie Me didn't keep them separated. Over the years, when I've used that alloy, I'd get BHN numbers from 12 to 18 in different batches of bullets.
Next, I have habit of dumping the metal rich dross from the previous casting session into the pot, then flux with a light layer of sawdust. This provides a insulation barrier to help the melter pot maintain consistent temperature, as well as a layer to help float the sprues I drop into the pot as I am casting (that practice is for pistol bullets only). So dross from the prior Auto-Battery term alloy casting session, ended up in both of the batchs of bullets I mention above. I have decided that habit of using the previous dross is a bad one. I will discontinue that, and just start saving all the metal rich dross for a range scrap smelting session. I cast inside, so I never do a thorough fluxing in the casting pot.
1st Conclusion and question:
I am still wondering exactly what is in some batches of my Auto-Battery term alloy, where just adding a lb or two of dross could jack-up the BHN that much?
2nd Conclusion and question:
The first batch I mention, 40% COWW, 60% soft, was cast in January (Minnesota). My casting room is upstairs in my 2+ story house and isn't really heated, the door is always open, as well as a open stairway, for heat to flow up there from the first floor where the wood stove it. That room can be as cold as 50º. So the question there is, could air-dropping bullets onto a towel (not in a pile), with ambient air being 50º, increase the hardness any, if even that much? (BHN 14, when it should have stayed around 11). That would be in addition to the Auto-Battery term alloy dross addition.
This turned out to be longer than I planned, there are a couple questions at the end, if you chose to read through this whole post.
I measure hardness of my batches of bullets quite often, and I regularly get "expected" results.
But, once in a while I get a batch of bullets that age hardens more than expected. I usually don't give it much thought and just save that batch of harder bullets for a different/increased load. I do keep a chronological log of each casting session, and try to enter BHN readings in there.
In the last few weeks, I've been loading ammo like crazy. (500) 38 super, (2000+) 45 acp, (2000+) 41 mag.
>One batch of bullets were cast (air-dropped) in Jan 2018 from 40% COWW, 60% soft.
BHN was 8 @ 1 hour (1-5-2018)
BHN was 11 @ 6 weeks (2-20-2018)
BHN was 14 @ 25 months (2-19-2020)
Another batch of bullets were cast (air-dropped) with straight COWW.
BHN was 10 @ 1 hour (9-29-2016)
BHN was 18 @ 4 years (2-22-2020)
...I wish I had another one or two measurements from 2016
When I looked into my casting Log, I seen that I had used my Auto-Battery term alloy prior to both of those casting sessions I mention above, where I got hardness anomalies. The story of the Auto-Battery term alloy is as follows. I got three 5-gal buckets of battery cables ends from a auto-recycler when I first started casting, there was a few strange items in the buckets which by look and feel, I figured they were soft lead...one item was reportedly a weight that Chrysler put in some steering systems? Anyway, I got a yield of about 200 lbs of ingots from those buckets. I smelt in 40 to 50 lbs batches. So there was 5 batches of ingots, that could have been different...and of course Newbie Me didn't keep them separated. Over the years, when I've used that alloy, I'd get BHN numbers from 12 to 18 in different batches of bullets.
Next, I have habit of dumping the metal rich dross from the previous casting session into the pot, then flux with a light layer of sawdust. This provides a insulation barrier to help the melter pot maintain consistent temperature, as well as a layer to help float the sprues I drop into the pot as I am casting (that practice is for pistol bullets only). So dross from the prior Auto-Battery term alloy casting session, ended up in both of the batchs of bullets I mention above. I have decided that habit of using the previous dross is a bad one. I will discontinue that, and just start saving all the metal rich dross for a range scrap smelting session. I cast inside, so I never do a thorough fluxing in the casting pot.
1st Conclusion and question:
I am still wondering exactly what is in some batches of my Auto-Battery term alloy, where just adding a lb or two of dross could jack-up the BHN that much?
2nd Conclusion and question:
The first batch I mention, 40% COWW, 60% soft, was cast in January (Minnesota). My casting room is upstairs in my 2+ story house and isn't really heated, the door is always open, as well as a open stairway, for heat to flow up there from the first floor where the wood stove it. That room can be as cold as 50º. So the question there is, could air-dropping bullets onto a towel (not in a pile), with ambient air being 50º, increase the hardness any, if even that much? (BHN 14, when it should have stayed around 11). That would be in addition to the Auto-Battery term alloy dross addition.