gmk@falstaff.mae.cwru.edu (Geoff Kotzar) (06/05/91)
In article <35200@mimsy.umd.edu> gmk@falstaff.mae.cwru.edu (Geoff Kotzar) writes:
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#(stuff deleted)
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# With regard to alloy I have never used Lyman #2 because
#the wheelweight supply has been very good in my area. Lyman #2 is
#a lot softer than straight WW so if anything I should have the more
#severe problem.
That last sentence is out of date and was based on a formula from
Lyman that has been in my files forever: it was printed in 1975.
That formula for #2 is 5.5# WW, 1# 50/50 bar solder, and 3.5# Pb.
The current formula is 9# WW and 1# 50/50 bar solder. The Sb content
has been reduced from 9% to something around 3%. Bullets cast from
current WW ARE softer than Lyman #2. This is according to the NRA Cast
Bullets book and Lyman 's Cast Bullet Handbook 3rd Ed. and a little
late night research.
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#I then took 5 of them and heattreated them. I do not have a Brinell
#hardness tester in our lab but we do have a Rockwell tester. On the
#"L" scale - 1/4 inch ball and 60 kg load - pure lead runs about a 5
#as-cast WW about 40-42, mono-type about 64, and ht-WW runs around 90.
#Annealed copper runs around 92.
#
The above hardness values are for the batches of wheelweight I have
used in the last 1-2 years. I am curious now because we have been
using ac-WW for rifle loads in 7x57, 30-40 Krag, 30-30, and 30-06
without leading problems and with acceptable to excellent accuracy.
Our velocities have been held to around 1800 fps for the most part
but even those pushed out at 2200 fps showed no signs of leading or
group deterioration. I am going to have to fill in the holes with
some more thorough testing next week.