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Old 03-15-2008, 09:53 AM
parisite parisite is offline
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Brinell Hardness/Velocity




Do any of you know if there is a chart on the net that tells min/max recommended velocities for lead bullets according to it's hardness on the Brinell scale?

I know you get leading going too far either way outside the perimeters of the lead projectile you are shooting and optimum accuracy is lost.
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Old 03-15-2008, 11:28 AM
shocktroop shocktroop is offline
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The Lee hardness kit has a cool table that has the hardness and the corresponding velocities. I think that if you go to thier site, over on the left of the homepage there are links in PDF for all of thier products, including the hardness test kit, see if you can download the intsructions/and data that come with it. I'm almost out the door, when I get back I'll see if I can get it and I'll post it up if I can find it.
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Old 03-15-2008, 12:46 PM
JohnC JohnC is offline
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I copied this off the Missouri Bullet Company website.

Optimum BHN = CUPS/(1422*.90)

The CUPS of your reloads is published in the reloading manuals. Take a typical .45 ACP load, using a 200-grain LSWC bullet 5.0 grains of Bullseye. This load develops 900 FPS and is in common use among IPSC and IDPA gunners. The reloading manual shows that the pressure generated by this load is 20,000 CUPS. So, the formula for optimal bullet hardness is

20,000 / 1279.8 = 15.62
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  #4  
Old 03-15-2008, 01:51 PM
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RetiredRod RetiredRod is offline
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The formula I got a few years ago from Mid-Kansas cast bullet company is: chamber pressure required for lead bullet obturation= brinell hardness number x 1422.
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Old 03-15-2008, 07:00 PM
lv2tinker lv2tinker is offline
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I think this is what you are looking for: http://www.frfrogspad.com/miscellm.htm

Cheers
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  #6  
Old 03-15-2008, 08:35 PM
parisite parisite is offline
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Now that I think about it, pressure, I guess has a lot more to do as to how hard of a bullet to use more than velocity. But how in the world would a layman shooter measure pressure? A chronograph would be a lot of help, but velocity and pressure don't always go hand in hand.
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Old 03-15-2008, 10:02 PM
lv2tinker lv2tinker is offline
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Quote:
Originally Posted by parisite View Post
Now that I think about it, pressure, I guess has a lot more to do as to how hard of a bullet to use more than velocity. But how in the world would a layman shooter measure pressure? A chronograph would be a lot of help, but velocity and pressure don't always go hand in hand.
All the Reloading Manuals list Powder Type, Grains, Velocity "and" pressure for Minimum and Maxium Loads. Example:
.45 ACP----------------------------------------------LEE Pressure Chart
230 GR LRN Clays--3.5 gr---716 fps ---13,700 CUP----BHN=10.1
------------Clays--4.0 gr---793 fps ---16,800 CUP----BHN=12.1

I use a BHN of 17.0 with 230 gr LEE tumble Lube bullets. 3.9 gr Clays with very-very light leading at the chamber. Gives 765 fps. Soft recoil.

Cheers

Last edited by lv2tinker; 03-15-2008 at 10:06 PM.
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  #8  
Old 03-18-2008, 09:35 PM
aneat aneat is offline
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There are a multitude of factors that come into play when youre trying to eliminate or prevent leading.
The fit of the bullet to the bore is the biggest factor.

For most 45acp bullets even pure lead can be shot with great results. For my bullets I cast I use 50/50 WW and pure lead mixed.
I had ballisticast cut me a H&G 68 mold for the bullets to come out the correct size and actually push them thru a .453 sizer. Being a softer alloy they come thru at .4525. I can shoot close to 1000 rounds between cleanings and have zero leading. One wet patch followed by a couple dry ones and the bore is clean.

The bore diameter, depth of the rifling, condition of the bore, type of powder, are several things that can cause leading problems.

For example lv2tinkers example of a 17bhn bullet and getting light leading at the chamber. That is an indication of an alloy that is to hard for the application. The bullet is not obturating to fit the bore and gatting a little flame cutting before the pressure rises.
Now he has to be careful if he starts throwing a softer mix in his pot. As you go softer in your alloy the bullets will come out smaller and smaller.
Get under the bore size to much and he can experience more flame cutting or get to a point wher the bullet will strip the rifling (not grip) and that will cause severe leading down the entire bore.

Getting the correect cast bullet for your gun can be a real challenge in some instances, luckily most "good" combinations have been sorted out in the past for us.
If youre getting leading look at the entire picture, sometimes the answer isnt so obvious.

Sorry if Im rambling on
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  #9  
Old 03-20-2008, 01:19 AM
parisite parisite is offline
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Great insight, aneat.
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