Choosing BHN

S

Shadow9mm

New member
So I am using lead bullets for 9mm and am getting into 38spl and 357 mag. I have been doing some research on bullet alloys and am considering getting into casting my own. I was looking at Missouri Bullets and their "hardness optimized" logo. While doing some reading I found their formula for ideal BHN here https://www.missouribullet.com/technical.php

Ideal BHN=PSI/(1422X.090)

Based on their formula
9mm, 35,000 PSI, 27BHN
9mm+P, 35,800 PSI, 30BHN
38spl, 17,500 PSI, 14BNH
38spl +P, 20,000 PSI, 16BHN
357 mag, 35,000 PSI, 27BHN

I find this odd as in my research I have not seen BHN this high and Missouri's alloys re not that hard
9mm, 18BHN
38spl, 12BHN
357 mag, 18 BHN.

I feel like I am missing something......
 
Shadow9mm said:
So I am using lead bullets for 9mm and am getting into 38spl and 357 mag. I have been doing some research on bullet alloys and am considering getting into casting my own. I was looking at Missouri Bullets and their "hardness optimized" logo. While doing some reading I found their formula for ideal BHN here https://www.missouribullet.com/technical.php



Ideal BHN=PSI/(1422X.090)



Based on their formula

9mm, 35,000 PSI, 27BHN

9mm+P, 35,800 PSI, 30BHN

38spl, 17,500 PSI, 14BNH

38spl +P, 20,000 PSI, 16BHN

357 mag, 35,000 PSI, 27BHN



I find this odd as in my research I have not seen BHN this high and Missouri's alloys re not that hard

9mm, 18BHN

38spl, 12BHN

357 mag, 18 BHN.



I feel like I am missing something......
Click to expand...
Marketing hype. Use a Lyman cast bullet manual for reference.

Sent from my SM-G781U1 using Tapatalk
 
"I find this odd as in my research I have not seen BHN this high and Missouri's alloys re not that hard"

I cast my own bullets for rifle and handgun. My base alloy is 11 on the BHN scale. I've run bullets from that alloy in 9MM, .357 Mag. and .44 Mag. at full power. I also run John Linebaugh level loads in Colt .45 in a Ruger Blackhawk Bisley with no leading problems from any of the above mentioned cartridges.

My alloy is a mix of wheel weight metal, linotype 95/5% lead free solder and #9 bird shot in measured quantities. As cast and air cooled BHN 11. Water dropped 19 BHN. Heat treated in a toaster over for for+ hours, then water dropped will reach 30 BHN and sometimes as hard as 32 on the scale. Most times I don't even bother and just use them as 11. I do pay particular attention on how the bullets fit the particular firearm, especially revolvers.
Paul B.
 
Shadow9mm,

Where those numbers come from is explained in detail in Richard Lee's Modern Reloading. He uses about 1280 rather than 1422 to have 10% headroom for shot-to-shot variation in pressure, but basically was able to show plain base cast bullets (no gas check) do shoot more accurately when this pressure limit is observed.

The numerical basis is that BHN is based on a sphere indenting the alloy under the force of a known weight, if you divide the weight by the surface area of the resulting spherical indentation, you will have the number of pounds per square inch of pressure that deforms the alloy. So what Lee did was avoid ever exceeding the deformation value. Doing that, you'll find that in a smooth barrel with cast bullets 0.001"-0.002" over groove diameter, you can frequently use no bullet lube or powder coating and still not get much metal fouling in the bore. If you shoot over that number, you will often need good lube or powder coating to avoid fouling.

For pistol accuracy purposes, the deformation is usually uniform enough that it doesn't make a big difference. Indeed, even with rifles, avoiding all base deformation is more a target shooting consideration than a hunting accuracy consideration, and gas checks protect bases well enough to keep accuracy decent with rifle bullets and magnum handgun bullets.

There is also a situation in which a soft bullet is preferable. That is when you have a bore constriction in a barrel, as is common with revolver barrels where they screw into the frame. In this situation, you need the bullet to be soft enough so bore pressure bumps it back up to bore diameter after it passes through the constriction. Otherwise, the gas seal to the bore is lost and gas cutting starts which both spoils accuracy and fouls the bore badly. Such revolvers will shoot more accurately with the soft bullets than they will with hard bullets that are sized down by the constriction, and then hold that undersize shape and are subject to gas cutting and tend to favor one side of the bore, causing them to drift away from the bore line on their way to the target.
 
Shadow,

And well you should find it odd. Think about it, Elmer Keith designed the .44 Magnum around a bullet with a BHN of 11. It's ridiculous to think you need a bullet with a BHN of 14 for a .38 Special. The bullet in the middle and to the right are from .38 Special +P loads, and their BHN is 8. Explanation of why their suggested BHN's are so high: To justify the alloy they buy so as to have their bullets hold up well during shipping.

Don

attachment.php
 
That's really good to know. Thank you. There is so much mis-informtion and lore out there. trying to understand how things really work is hard to find.
 
An alloy of 50% Clip on wheel weights + 50 % soft lead ( stick on wheel weights )
will give you a bhn of 8 ... and is an excellent all around alloy for handgun loads .
Add a gas check design bullet and a good alloy to use in magnum handgun and rifle loads.
When I had a free unlimeted supply of wheel weights I cast straight COWW for decades but have discovered cast bullets work better when softer ... the 50/50 mix is an ideal all around mix and works great with HP moulds .
Gary
 
Agree with you, gwpercle, a 50/50 mix of COWW and pure is a good handgun alloy. And, adding a little solder to the mix makes it even better.

Don
 
Last edited:
So 2 updates. I got some .359 bullets from Matts Bullets. A good friend of mine swears by them. They are .359. They will not pass through any of the throats with finger pressure. Now I just need to get my hands on some .358 and see how they fit.

Second updated. I e-mailed Missouri bullet company and asked the same question I Asked here. Here is the response. And yeah, I feel like they blew me off.

The quickest answer to this question is that our bullets cast at 12 BHN
need to be kept under 850 fps.

BHN of 18, below 1400 fps.

Thank you,
Click to expand...
 
They receive 2 alloys from their supplier. Pretty sure the one is 96% Pb and 4% Sb for 12 BHN. Don't know what the 18 BHN alloy consists of. Then they devise that formula to make use of both of their alloys. Yeah, they blew you off.

Don
 
USSR said:
Shadow,

And well you should find it odd. Think about it, Elmer Keith designed the .44 Magnum around a bullet with a BHN of 11. It's ridiculous to think you need a bullet with a BHN of 14 for a .38 Special. The bullet in the middle and to the right are from .38 Special +P loads, and their BHN is 8. Explanation of why their suggested BHN's are so high: To justify the alloy they buy so as to have their bullets hold up well during shipping.

Don

attachment.php
Click to expand...
What do you fire those bullets into to get them to mushroom so evenly?
 
Hi 7.62 man,

My medium is water-soaked newsprint. I find that just water, as in lining up milk jugs of water, is too hard. So I bundle up newsprint and put it into one of those storage bins that they sell at Walmart and fill it full of water. Another nice thing about this is, it leaves behind evidence of the "wound" channel. But, the main thing with the even mushrooming is using the right alloy. The alloy used in all 3 of these bullets was 97 Pb/0.5 Sb/2.5 Sn. Got to keep the antimony content down and tin content up for nice mushrooms. With too high an antimony content, one or more of those petals on the middle bullet would have broken off. As I said, the middle and right bullet were .38 Special +P loads at 845fps and 940fps respectively.

Don
 
Shadow9mm,

If you measure 0.359" for the throats with a caliper rather than a thimble micrometer, the fact your .359" bullets don't fit is no surprise. Bore slugging really has to be done with fairly pure, soft lead and measured with the micrometer showing you tenths of a thousandth of an inch.

If the 0.358's are snug, too, and if the bore doesn't slug at least 0.001" smaller than the throats, you will have to sandbag for accuracy and, if it doesn't do well, and especially if it doesn't do well with jacketed bullets, look at sending the gun to Ruger for cylinder reaming. Ruger has been known, as in my example, to undersize chamber throats. And, as in that example, they didn't have to be told what to do. We just sent the gun with a complaint about its accuracy. Be aware, though, that if you have done anything to alter trigger weight, they will put it back to factory spec as a liability CYA step, and any special springs or other parts will be lost.
 
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