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HB certified Master Handloading and Ballistics advisor
| Joined: | Sun Feb 6th, 2005 |
| Location: | Trinity, Texas USA |
| Posts: | 526 |
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I have done a test of alloys and waterdrop vs air cooling.
The protocol was;
Newly collected wws, tested BHN12-13 before melting and scrap lead that tested BHN5.
I cleaned wws in a small pot, then cast a bunch of 200gr .44rfn bullets.
Dumped the pot and melted a muffin of lead that tested BHN5, cast a bunch of 200gr .44rfn bullets.
Dumped the pot, cleaned it good.
Then made mixes of 8-1, 6-1, 4-1 ,2-1 and 1-1 of wws and lead.
Afert each mix was made and bullets cast, water cooled and air cooled , pot was dumped and a new mix was made, so all mixes are correct for proportions.
Results;
WWS H2O , BHN 22 Lead, a/c , BHN5
8-1, H2O , BHN 24 a/c, BHN 14
6-1, H2O , BHN 22 a/c, BHN 13+
4-1, H2O, BHN 16 a/c, BHN 13
2-1, H2O, BHN 14 a/c, BHN 13-
1-1, H2O, BHN 13 a/c, BHN 12
I have an Ingot of linotype from Midway, claimed BHN 22 and some recycle yard lead that tests BHN 5.
I am using a Cabine Tree tester that gives readings with a dial indicator.
I tried the linotype and the lead before I tested the bullets and the tester showed the expected readings, so I believe the tester.
Some of the readings surprised me, other posters on some sites indicated wws plus lead, 1-1 would be about BHN 8, my results are not that.
Richard Lee's experiments showed that a cast bullet would take pressure of 90%+ of the strength of the alloy without the bullet stripping in the rifling.
For reference,
BHN 24= 34,000 psi
BHN 22= 32,000 psi
BHN 16= 22,500 psi
BHN 14= 20,000 psi
BHN 13= 18,500 psi
BHN 12= 17,000 psi
BHN 8= 11,000 psi
BHN 5= 8,000psi
This is not related to velocity, but peak pressure.
If you use more of a slower powder, so the pressure is lower, you can get higher velocities if you have a barrel long enough to use the longer burn time.
Usually, you must use a slightly faster powder with cast bullets , rather than jacketed bullets, to get the same velocities as the jacketed bullets have more resistance to being pushed down the barrel and the powder can build more pressure, remember, pressure is what produces velocity, so with bullets that have less resistance, faster powders must be used to get the same velocities.
Don 
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