Testing Bullet mtl hardness

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  • Last Post 20 January 2016
JPnewhampshire posted this 08 January 2016

Back in the 50s I loaded 1000s of 38/357s for my buddies and myself. We scrounged lead from everywhere--celler holes, abandoned houses etc. after blending I would check the hardness by pressing a ball bearing between the blend and a pig of pure lead then measuring the width of the dents //  then SOME HOW get the relative hardness?/ I(at 78 age and65 yrs later) cant remember how I did it ???? Any help would be supper--JP  

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Westhoff posted this 09 January 2016

Almost had a bad case of old man's panic; couldn't find my copy of the formula you're looking for.

Take the diameter of the dent in lead, and divide it by the diameter of the dent in the sample. Square the answer (multiply it by itself). Multiply that answer by 5 (BHN of lead). That should give you the approximate BHN of your sample.

If you can find a copy of the NRA Cast Bullet Handbook, the formula is found in Col E. H. Harrison's article “Measuring The Hardness Of Cast Bullets", on page 22.

I've found it is much easier to do this with a fairly large ball bearing; at least 1 inch in diameter. I also found the easiest way to get good test samples is to pour them in an aluminum muffin pan. Don't try this with a TIN muffin pan, you'll never get the muffin out!

(Probably shouldn't use the pan to bake muffins in afterward, either.)

Wes

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Duane Mellenbruch posted this 09 January 2016

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JPnewhampshire posted this 09 January 2016

WOW: What fast responses// Thanks Westhoff-I hope to cast some pure L ingots and some hard stuff so I can blend it to around 20 BHN. --Gotta go find a ball bearing//--JP

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frnkeore posted this 09 January 2016

Make sure that your sample that you test against is PURE lead. It can throw the final result off if it not.

And keep it in a safe place so, you don't loose it. Then all your test results will be comparable. I've had my sample since 1987.

Frank

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JPnewhampshire posted this 09 January 2016

I asume that after a few usages on the (cup cake size ingot) you run out of space to make a new test???  Do you remelt it ??    Ps: Ijust ordered 3 1” bearings from Ebay--ship 3-4days///   JP

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Westhoff posted this 10 January 2016

I still have a small stash of reasonably pure lead - and yes, when I run out of 'dent” space I remelt and cast a few more lead muffins. I've never worried about developing an EXACT BHN. if it's close to lino, or close to some other hardness I'm looking for, I figure the rifle won't be quite so critical about bullet hardness that it refuses to perform like the last batch.

Wes

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JPnewhampshire posted this 14 January 2016

Question on testing procedure ? do you squeeze the lead-ball-sample in a vise or hit it with a hvy hammer ??

today I tried both -whacking with a lead mallet was fast but I got some bounce and a misshaped dent--the vise worked but you really gotta crank on the vise to get a .3+” dent Tomorrow I'm going to vise and hit the jaw a cpl times to get a bigger dent JP

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Westhoff posted this 15 January 2016

I never had a problem using a vise. One thing - the larger the ball bearing, the larger and easier to measure are the dents. Also, my vise is pretty good sized. And no, I never tried using a large hammer, and I don't think you'd get measurements nearly as accurate that way.

Wes

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Brodie posted this 15 January 2016

Instead of a hammer you would have better luck with a “guided” weight dropped from a specific height , and held straight to the target.  When old coins were struck by hand they had to train the strikers to hit the dies perfectly straight.  Otherwise, the coin was lopsided when struck.  Even a piece of pipe (say 4"dia.) could be used to guide the “Hammer” so that it hit the two pieces of lead squarely.  Brodie

B.E.Brickey

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frnkeore posted this 15 January 2016

What I use is a 2 ton arbor press. Not many reloaders have them but, if you do, they come in very handy for a lot of things. I do almost all of my case forming and bullet sizing on it. The 2 ton is the best all round size. Frank

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Mustafa Curtess posted this 20 January 2016

Back when I still believed that  1 or 2 bhn difference was important, I was frustrated by the effect that age / precipitation hardening had on my results. The notion of  alloying, testing, then adding lead or antimony as indicated, and re-testing, in one session, simply annoyed me - because actual CB's were invariably appreciably harder a couple of weeks later.  If there was ever a mathematical formula to predict final working-hardness, I somehow missed it.   I quickly came to prefer the SAECO Bullet (not “ingot")-hardness tester, because results (at any stage of precipitation hardness) is so much more consistent (& therefore credible). I was not impressed by the demonstration of the use of other types of testers - which seem to require multiple penetrations and the results averaged.  Quenching from the mold gives an instant test that is much closer to the final actual working hardness.  I get more useful information merely by squeezing two bullets from the same blocks together in a vise.  The comparison of the extent of deformation between the two samples generally tells me everything I really need to know - but, there again, both must be old enough to have stabilized. Stabilization can be accelerated somewhat merely by alternately freezing and thawing a batch of bullets a couple of times, but a few weeks later, test results will again differ a bit. It is sometimes equally important to know the final Bullet dimensions after aging, also.  With certain (exactly unknown) alloys, bullets several months old have to be re-sized to seat and chamber acceptably. The increased effort required to push them thru the sizer die also gives one something to ponder.

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