I thought I'd return and update the progress that I have made with the Bismuth/tin alloy tests.
To begin, the alloy from Rotometals in 93% bismuth and 7% tin. I tested a few times with that alloy mix and determined that the bullet was shattering in the bore. This explains the odd recorded velocities with the early tests. My biggest evidence to support this, early on, was the evidence left with the jugs. Studying the impact point of jug one, I can clearly identify multiple impacts.
Realizing that we were a far distance from where we want to git with this here alloy, so I upped the level of tin to 15%. I tested the 15%tin alloy and things still seemed to be much of the same. I ran one high velocity test and one Trail Boss test. At 15%, I still hadn't recovered a %@*&$ slug. NOT ONE! Yikes.
So, I didn't waste much time till I raised the tin percentage to 18%. I again tested a high and low velocity test, but this time, I recovered the first slug from these tests. The Trail Boss load recorded a velocity of 1366fps and the bullet was recovered in the 7th jug, having punched a hole through to the 8th.
As you can see in the pic, I raised the tin level to 21%. With my wheel weight alloy, the RD432-240 naked bullet weight is right around 242gr. With 21% tin/79% bismuth, the naked bullet weight is just over 200gr.
I failed to recover the slug from the high velocity test, but after cleaning up an scouring the ground, I found this.
That is a pic of a fragment from the base of the bullet. The fragment shows the base edge that I file to make it easier to get the gas check on. This means, that the bullet is shattering on impact with the high velocity tests.
So my next move is to raise the tin level to 25% and test again.
There are more tidbits I have learned about bismuth along the way, but this is too long already.
