Hardness

[ole95]

I traded for a Lee Hardness tester and tested a few bullets this is what I came up with
my alloy 8 parts WW ,1 Part Linotype, 1 part WW with 2% tin. this alloy works real good as for as casting full dia. bullets that I can size correct and shoot real good
My 30 cal. bullets 1200- 1300 mv. lube LBT soft
water drop 20.5 bhn
air cooled 18.5 bhn
from what I read 18 bhn is the norm/standard is 20.5 to hard for silhouette. Water drop fits my cast routine real good but if it is to hard then I can switch to air cool
really don't wont to mess with my alloy @ this time
Thanks
jrs

[high standard 40]

Richard,
I suspect something is not quite right with your data. You should not be getting near that harness with the alloy mixture you stated. I use an alloy of 4 parts COWW to 1 part Linotype with some added tin and water drop and get 18BH. I have a "Lead Alloy Calculator" spread sheet and the alloy you stated you use should yield an air cooled bullet of 12.8 BH.

Linotype is supposed to be 19-22 BH (I have seen varying data here)
COWW is supposed to be about 10-12 BH ( this can also vary, maybe lower not higher)
Tin does little to harden especially with the small amount you are using.

Add up the quantities and values you are using and it's hard to see getting near 18BH air cooled.

[high standard 40]

To further address your original question, some people believe that straight Linotype with it's high antimony content is too brittle for silhouette and you will loose efficiency on rams. A softer bullet works better in this regard. If you achieve a harder bullet by either water dropping from the mold or oven heat treating, the resulting harder bullet will maintain a large degree of the malleability of the base softer alloy and will not shatter on the target like Linotype will. I have found that with my 7TCU, I had to get to about 18BH before I could get the accuracy I needed. So to answer your original question, for silhouette I would use the softest alloy I could that would yield an accurate load and not lead the barrel. It sounds like you have already found your load.

For further knowledge go here and read. http://www.lasc.us/CastBulletNotes.htm

[ole95]

Thanks Charlie you very well could be right after reading your reply So I went and did some more testing on different parts of my Alloy
my Linotype 20.9
my Wheel weights 14.3 (these I have had for over 30 years I guess the don't make um like that anymore LOL)
my WW +2%tin 16
When I 1st. started casting I was using more linotype and I sent a a few samples to Wayne S and he had them check I went back and reread his E-mail
his test
Water dropped 23.5
oven heat treated 23.5
air cooled 13
and like I said after I got his results I cut back on the linotype so I'm thinking my now water dropped 20.9 is pretty true reading
running the numbers you have yes runs bout 12+ running the numbers that I got (higher on ww) I get 15+ still not sure what's up with the 18 I read but will retest
My air cooled may have not been a true test when I got the lee tester the only or close to air cooled bullet I had was one that I had left in the mould
from my last casting day with the pot getting low. So next casting day I will air cool several and retest
I guess the best testing is just slamming steel and that's 2 months away

[marshall623]

This is a interesting read here , I have some 160 lyman cast from COWW / 4 % tin and water quenched from last season . I tested these by 1 of the DIY methods from LASC cast bullet write ups and come up with a BHN of 13 . I was expecting around 22-24 because I suspected I had too hard of bullets , I wouldn't think they would age soften in less than a year. I all ways added tin to a 10# pot maybe inconsistent blending ? I melted down down all my 4% ingots with COWW 20# at a time to get 2 % tin and cast some with a 358477 mold water cooled and after 2 weeks I come up with 18.5 BHN. Lyman cast bullet book 4 has a lot of good stuff that has really got the gears turning. What I do know is my 7-08 Striker does not like air cooled COWW or COWW with tin . I've always cast the 130 lee's with straight COWW's and water cool I am tying them with 2 % tin to toughen them up a bit

[Richard Pickering]

Tim, as you mention, adding tin to an alloy is for the purpose of making it flow and fill a mould better. I have read from several sources that using more than 2% tin is wasting it. What hardens lead alloys is Antimony. Typesetting alloys---Linotype or Stereotype have increased Antimony content.
Water quenching helps hardness as does heat treating to a greater degree. The inclusion of a small percentage of Arsenic has been mentioned as increasing hardness of alloys containing higher Antimony. Arsenic is gained by using chilled shot as part of the mix. We should never attempt to use Arsenic in any other form. Richard

[ole95]

Tim take any thing I say with a grain of salt but you can bet the farm on what Charlie , Richard and a few other post here !
Right now I'm doing a little testing. Yesterday I reduced my lino form 1lb. per 10 to 1/2 per 10. cast about 30 bullets (165sil) air cooled half and water dropped half
waited one hr. and checked a few both ran about 14.9 I had read that the affects of water dropping take from 24 to 48 hr. to show. Today (24hr.) I rechecked air cooled still around 14.9 but the water dropped were @ 20.1 I will recheck tomorrow(48) and post my findings

food for thought taken from the Lee Hardness tester
"for every 1% tin Bh increases 0.29"
"for every 1% antimony BH increases 0.92"
"Brinnell hardness = pure lead 8.60 +(0.29xtin%) +(0.92xAnt. %)
to go with what Charlie said adding 2% tin has little affect on BH about .58 were as adding 2% antimony would increase 1.84
I would like to see the different affect of bullets @ say 15bh and 22bh @ my load speed of 1000fps @ the ram line
I can agree with the logic that harder shoots better and softer take down rams and I guess were all looking for that optimal BH # that combines both
jrs

[ole95]

rechecked today and as figured air cooled had not changed but the water drop had was up to 22.7
my new plan is to air cool test for accuracy and leading if there is a problem I will oven heat treat until I get the results I'm looking for
and if I'm correct on this I can cast > store then oven heat treat on a as need be basics size lube load and fire
I'm not sure but would think something in the 14-15bh would work @ my under 1300mv.

[high standard 40]

Richard,
One thing to consider with heat treating lead alloys. In effect what you are doing aligning the molecules which strengthens the alloy. This effect takes a few days to fully harden as you have found. But if you take a fully hardened heat treated bullet and then run it through a sizer die, you move some of the metal and you will loose some of the hardness. The ideal process is to cast the bullets, size as needed, then oven heat treat and quench. After quenching, I then run the bullet through a sizer die .001" larger to lube, just to be sure I don't "move any metal". An alternative process is to water drop from the mold and size as soon as possible, don't wait. There is a detailed discussion of all this on the LASC website. http://www.lasc.us/HeatTreat.htm