JimGnitecki
Member
- Joined
- Mar 28, 2010
- Messages
- 1,258
As you all know, a key attribute of unjacketed lead bullets, that makes them either great or bad for accuracy and barrel leading, is their hardness as measured on the Brinell Hardness Number system. Most commercial bullets are too hard for use on low velocity / low pressure handholds. They are made relatively hard to prevent damage in shipping, but that hardness makes their performance inferior for use in low pressure handholds.
But to cast your own softer lower Brinell Hardness Number (BHN) bullets, you need to be able to measure the hardness of lead alloys reasonably accurately.
I live in Canada and ordered the Lee Hardness Tester from a Canadian vendor on Wednesday and received it the next day on Thursday (That Canadian supplier apparently ships QUICKLY, and Canada Post CAN perform when it chooses to do so!).
But the Lee kit as equipped by Lee is known as being a bit difficult to use, primarily because most people cannot hold the Lee “pocket magnifier” steadily enough, at the exact right height for decent focus, and exactly over the tiny indent (typically under .060” for commercial bullets) on the bullet or lead sample, while simultaneously holding a light of some sort, trying to read the tiny Lee diameter scale (0.000” to 0.100”) to determine the diameter of the dimple made using the Lee tester.
I had on Wednesday found a very nice YouTube video where the poster had purchased a $35US 3D-printed “microscope stand” specifically designed to hold the Lee pocket magnifier, but who had also developed an alternative solution that cost about $1. His solution was to buy a set of plastic funnels from a Dollar Store, and use one of the funnels, slightly modified, as the magnifier holder, along with an LED flashlight. I basically copied his setup after visiting the local Dollar Tree store, where I bought a set of plastic funnels for $1.58.
Here’s a photo:
I started with a 5.5” x 5.5” piece of paper, onto which I scribed a corner to corner crosshair to be able to reliably center the Lee Magnifier (the device in the photo that looks like a pen with a pocket clip). I marked centering guides on the crosshair, with a diameter just slightly larger than the lip diameter of of the funnel. That enables accurate entering of the funnel.
I progressively clipped the tapered output end of the funnel until it was JUST large enough to hold the Lee Magnifier with sufficient friction, but enabling up and down adjustment of the magnifier, in order to be able to get exactly the right height above the bullet or lead sample for a good focus.
I cut a hole in the side of the funnel to enable me to shine a strong LED light onto the sample being measured.
To use the setup:
- I use the Lee “dimpling” device in my standard Lee reloading press to make a dimple in the sample bullet or piece of lead ingot, in the standard correct 30 second duration pressure method
- I place the bullet or ingot sample onto he paper “target sheet”, centering it on the crosshair.
- Place the funnel onto the paper, entered over the crosshair using the marked guide points on the paper sheet.
- I adjust the height of the magnifier downward until it is the correct (approximately 3/32”) distance above the sample surface for good focus.
- Keeping the funnel lightly pressed against the paper, I move it around slightly until the built-in dimple diameter gauge properly spans across the dimple.
- I note the diameter of the dimple on the sample.
- I compare the diameter of the dimple to the crib sheet provided by Lee, to determine the approximate BHN, and the resulting recommended pressure range for the handload in order to optimize bullet obturation.
As expected, both of the 405g commercial 45-70 bullets I tested this morning are a bit too hard to enable good bullet obturation in the firearm barrel, when using a low pressure (“Trapdoor”) 45-70 handload in my Pedersoli buffalo rifle.
But now I have a setup that will enable me to measure the approximate BHN for any softer custom alloy I create using a blend of Linotype and pure lead.
I still will likely order the $35 3D printed microscope stand, just to get easier and faster and more precise positioning, focus, and lighting, but the funnel and paper setup will get me by while I wait for the 3D stand to get shipped and arrive!
If you look very carefully at the 45-70 .459” diameter bullet in the photo, located around ”7pm” relative to the funnel, you can see the very tiny dimple created in its top by the Lee dimpling device on the reloading press. THAT’s what we are trying to accurately measure the diameter of!
Jim G
But to cast your own softer lower Brinell Hardness Number (BHN) bullets, you need to be able to measure the hardness of lead alloys reasonably accurately.
I live in Canada and ordered the Lee Hardness Tester from a Canadian vendor on Wednesday and received it the next day on Thursday (That Canadian supplier apparently ships QUICKLY, and Canada Post CAN perform when it chooses to do so!).
But the Lee kit as equipped by Lee is known as being a bit difficult to use, primarily because most people cannot hold the Lee “pocket magnifier” steadily enough, at the exact right height for decent focus, and exactly over the tiny indent (typically under .060” for commercial bullets) on the bullet or lead sample, while simultaneously holding a light of some sort, trying to read the tiny Lee diameter scale (0.000” to 0.100”) to determine the diameter of the dimple made using the Lee tester.
I had on Wednesday found a very nice YouTube video where the poster had purchased a $35US 3D-printed “microscope stand” specifically designed to hold the Lee pocket magnifier, but who had also developed an alternative solution that cost about $1. His solution was to buy a set of plastic funnels from a Dollar Store, and use one of the funnels, slightly modified, as the magnifier holder, along with an LED flashlight. I basically copied his setup after visiting the local Dollar Tree store, where I bought a set of plastic funnels for $1.58.
Here’s a photo:
I started with a 5.5” x 5.5” piece of paper, onto which I scribed a corner to corner crosshair to be able to reliably center the Lee Magnifier (the device in the photo that looks like a pen with a pocket clip). I marked centering guides on the crosshair, with a diameter just slightly larger than the lip diameter of of the funnel. That enables accurate entering of the funnel.
I progressively clipped the tapered output end of the funnel until it was JUST large enough to hold the Lee Magnifier with sufficient friction, but enabling up and down adjustment of the magnifier, in order to be able to get exactly the right height above the bullet or lead sample for a good focus.
I cut a hole in the side of the funnel to enable me to shine a strong LED light onto the sample being measured.
To use the setup:
- I use the Lee “dimpling” device in my standard Lee reloading press to make a dimple in the sample bullet or piece of lead ingot, in the standard correct 30 second duration pressure method
- I place the bullet or ingot sample onto he paper “target sheet”, centering it on the crosshair.
- Place the funnel onto the paper, entered over the crosshair using the marked guide points on the paper sheet.
- I adjust the height of the magnifier downward until it is the correct (approximately 3/32”) distance above the sample surface for good focus.
- Keeping the funnel lightly pressed against the paper, I move it around slightly until the built-in dimple diameter gauge properly spans across the dimple.
- I note the diameter of the dimple on the sample.
- I compare the diameter of the dimple to the crib sheet provided by Lee, to determine the approximate BHN, and the resulting recommended pressure range for the handload in order to optimize bullet obturation.
As expected, both of the 405g commercial 45-70 bullets I tested this morning are a bit too hard to enable good bullet obturation in the firearm barrel, when using a low pressure (“Trapdoor”) 45-70 handload in my Pedersoli buffalo rifle.
But now I have a setup that will enable me to measure the approximate BHN for any softer custom alloy I create using a blend of Linotype and pure lead.
I still will likely order the $35 3D printed microscope stand, just to get easier and faster and more precise positioning, focus, and lighting, but the funnel and paper setup will get me by while I wait for the 3D stand to get shipped and arrive!
If you look very carefully at the 45-70 .459” diameter bullet in the photo, located around ”7pm” relative to the funnel, you can see the very tiny dimple created in its top by the Lee dimpling device on the reloading press. THAT’s what we are trying to accurately measure the diameter of!
Jim G
