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Old March 6, 2011, 08:36 AM   #1
steve1147
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Brinnell hardness discrepancies?

Hello All,
With my recent accumulation of unknown lead and alloys I finally bought a Lee hardness tester.
Now, unless I'm doing something wrong, and I've repeated this several times, when I test the one pound ingots of smelted wheel weights, I get a reading of .050 (bhn: 20.9), but when I test the bullets recently cast from these same ingots (230 gn 45acp), I get a .055 (bhn: 17.2). Am I missing something here, does the smaller bullet just allow more expansion of the indent or did someone sneak some pure lead into my pot before the last casting???
Thanks! Steve W.

PS to above: While either of these looks fine and work fine for my .38 and .45acp's, I'm getting ready to start casting for my 40 s&w and it looks like I'll need to harden this up for it's high pressures. I've got 5# each of antimony(pre-alloyed with lead) and tin coming from Rotometals. Any experience of getting ww's up to proper hardness for .40 cal?
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Last edited by steve1147; March 6, 2011 at 08:50 AM.
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Old March 6, 2011, 10:36 AM   #2
reloader28
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Older lead will read harder than newer smelted lead.
Could be that your casting and smelting temp and cooling speeds were different.
I dont bother checking my ingots for hardness. mainly cause they are straight WW ingots and I know it. I run my melting pot at basically the same temp all the time and the boolits run a pretty consistant hardness.

If you want harder boolits, just water drop or heat treat them. They will come out as hard as you need them even for max loads. No need to add other expensive metals. This is what I do anyway.
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Old March 6, 2011, 04:45 PM   #3
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Yep fresh poured bullets will check softer than the ingots !

Give em a couple days to check em then again in a couple weeks & see what happens !

Your alloy seems to contain enuff alloys for the 40 (the scale is`nt as accurate with pistol bullets) & I usually use an alloy of 10bhn for all but the highest pressure revolver & rfle loads .

If the bullets fits the chamber & bore the softer alloys will usually withstand alot before leading ,but once that limit is reached it`ll all go south fast !!!!

The name of the game is to keep the pressure behind the bullet!!!
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Old March 7, 2011, 07:50 AM   #4
steve1147
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Guess I'll try casting some 40's with the ww only and try water quenching to see what I get. I can use the antimony and tin to alloy about 100# of pure lead I've got if I don't need it for the ww's. I've heard a thousand different opinions on percentages. The last batch I did was 90/5/5, but I've read that much tin and antimony may not be necessary? Hate to waste the expensive stuff!
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Old March 7, 2011, 08:19 AM   #5
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Tin

Steve

as far as hardening & castability more than 2-3% tin is a waste of alloy , it`ll only do so much then the level of benefit goes down fast !

I try to use an alloy around 10-11 bhn for 357mag HPs I take it to 5% tin to tuffen up the bullet without making it brittle so the HP does`nt break off upon opening , well with the tin at 5% I have no problem at 1200-1250 fps

If I need a tuff nonexpanding bullet I usually turn to WW & WD it to get a hard bullet, but still the thought is still there will the bullet shatter if I hit a bone ????
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Old March 7, 2011, 06:19 PM   #6
steve1147
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See, this is what confuses me, the manuals show .357 mag pressures at 30-40K psi, and 40 cal in the same arena. The little book that came with the hardness tester shows a 10.1 bhn should have a max pressure of 12895, fine for most 38 and 45 loads, but nowhere close to the pressures of 40 cal.
What am I overlooking?
Thanks, Steve W.
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Old March 7, 2011, 07:45 PM   #7
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You're overlooking nothing. Either reduce your pressure or use a different bullet (like adding a gas check).
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Old March 7, 2011, 08:06 PM   #8
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Don’t know what the little book says, but my .375 Winchester Model 94 runs about 45-50000 psi and all I shoot is straight wheel weight, 1800+ fps, no problems. Quenching makes them a bit harder, although it may not be necessary. Sorry, but I have no idea what the BHN is.
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Old March 7, 2011, 08:13 PM   #9
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The Lee scale

DO NOT LOOK AT THE SCALE !!!

The scale is just a guide line !! but if the bullet fits & the base is supported well where`s the lead gonna go if it does deform the bases ???? tighter against the barrel that`s where !!

Now if you have the slightest imperfection on the base or the bullet skids & opens the door for gas cutting all bets are off !!

If you can push a jag & patch smoothly down your bore you`ll do fine !!

If in doubt check the bore every magazine full to monitor foulin !!

Start at the bottom & work ya way up & the slower powders are more forgiving on lead projectiles .
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Old March 7, 2011, 08:20 PM   #10
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The little book is based on Richard Lee's method on determining necessary hardness, which is to make sure pressure doesn't exceed the yield of the alloy. This results in a harder number than most conventional formula's ask for, but Lee has some evidence of advantages for it. Read Lee's Modern Reloading, 2nd Edition for details.

My Lee tester reads higher than my LBT tester and higher than what I know about the alloy suggests it should read. I have not, however done systematic enough testing to eliminate all sources of error in the test, so my jury vote on it is still out. If the spring did not press the ball hard enough, that also would do it. The indentation diameter ratios, though, would hold, so once you measured a standard sample, like a bullet cast of pure lead (BNH 4.2) you could figure out the others.

Code:
BHN	Indent diameter ratio to pure lead indentation diameter
4.2	1.0000
5	0.9225
6	0.8470
7	0.7873
8	0.7385
9	0.6979
10	0.6633
11	0.6335
12	0.6072
13	0.5840
14	0.5632
15	0.5445
16	0.5277
17	0.5122
18	0.4980
19	0.4850
20	0.4729
21	0.4617
22	0.4512
23	0.4413
24	0.4323
25	0.4236
26	0.4155
27	0.4079
28	0.4005
29	0.3937
30	0.3871
31	0.3809
32	0.3750
33	0.3694
34	0.3639
35	0.3588
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Old March 7, 2011, 08:32 PM   #11
steve1147
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Thank You Uncle Nick

I get so many differing opinions, but I've read A LOT of your stuff and you know your way around the block. Please re-read my original post at the top and give your advice.
Thanks! Steve W.
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Old March 9, 2011, 10:44 AM   #12
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Steve,

My advice was going to be to run a test on some pure lead to calibrate against, but thought I'd better try it first, since Lee's published scale for the tool stops at BHN*8. Well, the resulting indentation (Hornady pure lead ball filed in half) was too big for the scale on the microscope. The problem is that it was too big by too much. I ran the Brinnel formula for the 5/32" ball bearing used in the Lee tool and their 60 lbs force and got exactly the numbers on their chart. The problem is that should only have gone to 0.105 for pure lead and the dent I got was probably 0.010" bigger than that.

So, I'm going to have to figure that out. It may have something to do with it being swaged rather than cast, but I need to prove that. It's the opposite of the too-hard numbers I was getting before. I've got some pure lead brick surplussed out from the dismantling of a university nuclear lab. I've also got some instruments to let me calibrate the force applied by the plunger and I'll let you know how that comes out. When I get it solved, I'll be able to give you a more sound recommendation.

Nick
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Old May 23, 2011, 01:08 PM   #13
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I have tried only one hardness tester. I won't say which for fear of getting sued. I got wildly different readings from the same batch of bullets. But why complicate life, when alloy hardness is so easy. All you have to do is get the alloy mix right. Any particular mix will have a specific hardness, which will be the same for that mix, every time. I have those hardness figures somewhere, but they will be in any metals handbook.

There's nothing special about the 40S&W, it is just another calibre, quite similar to the 9mmP in chamber pressure and MV. 6% Antimonial alloy is the cast bullet industry standard for handgun bullets, and is good for 1300 FPS in any calibre. You don't need to know the Brinell hardness, you need 6% antimony in your alloy, that's all you need do, and forget the hardness testers. How much simpler can it be ?

I'm a commercial caster, and need to cast very consistent bullets day in, day out. I have a bunch of very satisfied customers who shoot my bullets from every imaginable type of firearm, without significant leading or other problems. Including Glocks. There's nothing special about Glocks, you can ignore all that BS about cast bullets being a problem with Glocks.

You can also safely do without aftermarket barrels. They are not available in South Africa, and several of my customers shoot cast bullets in the factory barrels of their Glocks, including the 40S&W.
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Old May 23, 2011, 09:11 PM   #14
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Try the alloy you have, good chance it will work just fine. There's nothing magical about hard bullets. Leading is a symptom of poor fit or high pressure. It may be difficult to avoid high pressures with a .40 but it's worth a try.
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