30 March 2014
I will borrow my Mother-In-Law's camera this evening and take some pictures and post them. It sounds like your freind's design is very similar to mine!
My Lyman cast bullet handbook says to multiply 5 times the indent in lead over the indent in the sample (5 x Pb/Sample) to get the BHN. I have a manufacturing engineer's handbook I use for work that gives a more complex formula based entirely on the diameter of the penetrator and the applied load. This allows one to test the BHN of any material, but a hardened steel ball penetrator would be needed.
We use mostly 304 & 316 stainless, Monel, Hastaloy, and Inconel X625 at work. We occasionaly use duplex stainless and alloy 20 stainless. I made the tester out of 416 stainless scraps we had on hand. When we recieve these materials from the supplier, it comes with a certificate showing the exact proportions of the alloy, the heat number of the melt, and the physical properties. The hardness is always given in BHN. The customers we ship parts to always require a copy of these certificates. The heat number of the material is always written on the copy of the drawing of the part and filed in the shop office with each order.
This gave me the idea of assigning heat numbers to my batches of alloy. I use a 5 qt cast iron pot to mix a relatively large amount of alloy ( about 75 lb's) I then pig it out into 1 & 5 lb ingots and fill my 1.5 qt casting crucible. I take all of these ingots to the shop and stamp my heat number on them. This heat number stays with each run of bullets and I weigh a couple of dozen to see what the weights will be. I have always wanted to be able to check the hardness as well. I also 'mash test' some bullets on a small hydraulic press to see if they will expand properly.
I am basically using Lyman No. 2 alloy. I mix 1 lb of 95% tin 5% antimony Pb free solder to 20 lb's of wheel weight metal. The 'mash test' shows no brittleness at all. My favorite load is the Lyman 311284 bullet (210 grs.) with 43 grs. of IMR 4064 on a .30/06 1903 Sringfeild Mk1 with a “C” type stock. Dead animal carcas testing shows this to be a deadly load with plenty of knock-down power. The exit wounds are on par with factory softpoint loads. There is no leading at all in the 4 groove barrel. Velocity is in the 2400 fps range.