JimGnitecki
Member
- Joined
- Mar 28, 2010
- Messages
- 1,258
I am planning to cast 500g .459" and .460" bullets for use in my Pedersoli Sharps rifle.
I want to ensure good obturation, especially since the Pedersoli barrels apparently taper a bit from chamber end of the barrel to the muzzle.
The 5744 powder "Trapdoor" load that I intend to ladder test shows a maximum pressure of just 16,100 psi.
The crib sheet that comes with a Lee Hardness Tester suggests that for a maximum pressure that low, the Brinell Hardness number should be about 12.5.
I have available Lyman No. 2 ingots (I lucked out at a local metal salvage yard that had 15 lb) that are apaprently BHN = 14.7. I also have Hornady swaged .357 Magnum bullets that are pure lead or very darn close to pure (They are so soft that the Lee Hardness Tester crib sheet does not go to an indent size large enough - that crib sheet stops at a .079" indent which corresponds to BHN = 8.0)
Using an online Excel worksheet that shows the typically found lead alloys and their BHNs, and allows you to calculate the BHN of any lead bullet alloy using the formula:
BHN = 8.6 + 0.29 x %Tin + 0.92 x %Antimony
That worksheet and formula seems to suggest that if I combine:
3 lb of the Lyman No.2 (5% Tin, 5% Antimony, 90% Lead)
1.6 lb of pure Lead Hornady bullets
I will end up with a BHN of 12.5, and enough Lead to theoretically cast 4.6 lb x 7000g per lb / 500g per bullet = 64 bullets. I only need 45 bullets for the initial ladder test, but the extra poundage of Lead will keep the melting pot from running dry and enable me to create some bad bullets while I dial in the correct successful casting process.
The Tin and Antimony percentages will be diluted from 5% to 3.3%, but that is still enough Tin to fill out the mould, right?
To those of you who are experienced bullet casters: Does this sound correct to you?
p.s. I realize that 5744 in a Pedersoli rated for over 30,000 psi can be loaded much hotter, but I would like to first try the 16,100 pis Trapdoor load because:
- That's what the U.S. Calvary and buffalo hunters actually had to work with back in the day, and they made it work
- The recoil of that rifle with even a mild 405g @ 1250 fps load was pretty strong, even with a recoil pad, and I am not into unnecessary self-harm!
Jim G
I want to ensure good obturation, especially since the Pedersoli barrels apparently taper a bit from chamber end of the barrel to the muzzle.
The 5744 powder "Trapdoor" load that I intend to ladder test shows a maximum pressure of just 16,100 psi.
The crib sheet that comes with a Lee Hardness Tester suggests that for a maximum pressure that low, the Brinell Hardness number should be about 12.5.
I have available Lyman No. 2 ingots (I lucked out at a local metal salvage yard that had 15 lb) that are apaprently BHN = 14.7. I also have Hornady swaged .357 Magnum bullets that are pure lead or very darn close to pure (They are so soft that the Lee Hardness Tester crib sheet does not go to an indent size large enough - that crib sheet stops at a .079" indent which corresponds to BHN = 8.0)
Using an online Excel worksheet that shows the typically found lead alloys and their BHNs, and allows you to calculate the BHN of any lead bullet alloy using the formula:
BHN = 8.6 + 0.29 x %Tin + 0.92 x %Antimony
That worksheet and formula seems to suggest that if I combine:
3 lb of the Lyman No.2 (5% Tin, 5% Antimony, 90% Lead)
1.6 lb of pure Lead Hornady bullets
I will end up with a BHN of 12.5, and enough Lead to theoretically cast 4.6 lb x 7000g per lb / 500g per bullet = 64 bullets. I only need 45 bullets for the initial ladder test, but the extra poundage of Lead will keep the melting pot from running dry and enable me to create some bad bullets while I dial in the correct successful casting process.
The Tin and Antimony percentages will be diluted from 5% to 3.3%, but that is still enough Tin to fill out the mould, right?
To those of you who are experienced bullet casters: Does this sound correct to you?
p.s. I realize that 5744 in a Pedersoli rated for over 30,000 psi can be loaded much hotter, but I would like to first try the 16,100 pis Trapdoor load because:
- That's what the U.S. Calvary and buffalo hunters actually had to work with back in the day, and they made it work
- The recoil of that rifle with even a mild 405g @ 1250 fps load was pretty strong, even with a recoil pad, and I am not into unnecessary self-harm!
Jim G