Hardness-Optimized Bullets

Discussions of bullet casting, sizing, etc.

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daboone
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Hardness-Optimized Bullets

Postby daboone » Sat Dec 31, 2011 10:37 pm

Found this article over at Missouri Bullet Company site. If you'd like to better understand how bullet hardness effects on you barrel, leading and accuracy give it a look.

http://www.missouribullet.com/technical.php

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mascotal
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Postby mascotal » Sun Jan 01, 2012 12:20 am

I read that article once before and decided to test some store bought cast bullets I had that were made by DRG. I was using them for cowboy action 45 LC. I rigged up a bullet tester using my drill press, then using a solid lead bullet made sure I had my homemade rig calibrated. Sure enough, the DRG bullet tested out at 26 BHN.

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Jumping Frog
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Postby Jumping Frog » Sun Jan 01, 2012 3:04 am

Nice formula. Richard Lee's Modern Reloading book also correlates appropriate lead hardness with chamber pressure.

Although MB tells your the hardness, that doesn't help bullet casters using various forms of scrap lead. You can purchase a hardness tester, or you can take the "poor man's" approach, below.

You can get a good idea of relative hardness using artist's graphite pencils. There's a writeup on Castboolits forum.
The typical pack of artist's pencils has a set of 4,5,6 pencils of different hardnesses. You want the graphite pencils for this test. A set of pencils lasts a very long time and costs under $10.

Hardness ranges in a typical set are 6B (the softest) up to 6H (the hardest). A standard #2 pencil is HB hardness which corresponds roughly to 15 BHN which is approximately Lyman #2 Hardball.

The typical pencil hardness ranges:

Softest
6B Dead soft pure lead 5BHN
5B
4B Swaged lead/Isotope container lead, Speer soft lead bullets, Hornady buckshot
3B 1:20 alloy, 10BHN
2B Range Scrap (mixed)
B Clip Wheel Weights 1:10 alloy
HB (#2 pencil) Lyman #2 "hardball" alloy (92-6-2) 15 BHN
H Linotype
2H
3H Monotype 20BHN
4H
5H
6H Foundry Type 25BHN
Hardest

Water quenching lead alloys with antimony will typically bump them up in hardness depending on age of alloy 1-2 places on the Pencil Scale, about 5BHN maximum. Range scrap alloy usually tests out at "2B" unquenched and "B" quenched. Not much antimony in range scrap since it is mostly the soft cores of FMJ bullets & shotgun slugs mixed with whatever cast bullets are found. Clip wheel weight ingots test out at "B" air cooled but the water-quenched bullets test at "HB" after a few weeks.

Basically, take your sample of lead. Find a nice flat spot to test. Select the pencil you want to use. Sharpen the pencil at a nice 45 degree angle, leave the tip not needle sharp, but flattened on the end. Hold the lead at a 45 degree angle to the lead sample as if you are writing on it. Push the pencil backwards of normal writing direction, trying to use the tip to shave off a sample of the lead. If the pencil is harder than the lead it will cut off a curl of lead. If the pencil is softer it will skid across the surface of the lead, it might leave a line or mark on the lead but not cut it. Try this with different pencils until you find the one which just cuts the surface of the lead. The hardness of the lead is the next pencil softer.

For example, if a 2B pencil just barely cuts the lead, your lead hardness is about 3B, which is 10BHN approximately.

This procedure is used a lot more than you might think I have a friend who uses it for testing paint coat hardness pretty frequently and while it is not scientifically accurate in terms of absolute precision, it gives a good ballpark estimation which is good enough for cast bullets.

So, keep a stub of a #2 pencil in your pocket whenever you go to a junkyard or potential lead source. It's a simple, cheap and reliable way to get a rough guess as to what sort of lead alloy you find. If it scratches with a #2 pencil it is soft. If it won't scratch it is hard.

I like most pistol bullets to be in the 2B/B range which is about 12 BHN. When properly sized it has been the best for 45 ACP, light 44 Mag, 9mm, etc. When I shoot Magnums I use HB hardness (about 15BHN) again, sized to match the barrel bore.

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mascotal
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Postby mascotal » Sun Jan 01, 2012 3:48 pm

Good advice Frog.
I figure an educated guess is plenty good enough when it comes to cast bullets and the type of shooting most target shooters do. I have not actually shot any of my cast bullets yet, but the theory of softer lead makes perfect sense, especially for cowboy action. The whole idea is to save as much money as possible while still having fun shooting. I just don’t think the average re-loader needs to buy expensive testing equipment. Missouri Bullets has reinforced yet another reason for casting your own. Not only do you save a pile of money, you also get better bullets for your efforts that are more suitable for your gun and for range use. Softer lead will also extend the life of steel targets, like those used in Cowboy action. Black powder 45 LC and a 26 BHN bullet will badly damage cowboy targets.


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