Colonel Harrison on bullet alloys

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  • Last Post 11 August 2015
mtngun posted this 09 August 2015

I recently re-read the NRA Cast Bullets book and picked up a couple of details in the fine print that I hadn't noticed before. On page 144, there is a footnote that says Continued experience indicates that linotype alloy, BHN 20-22, generally improves the reliability of target grouping in even these very light loads.That agrees with my experience that hard bullets are good and that obturation is not necessary as long as the bullet diameter is correct to start with.    :) 

On page 14, there is an article on Is Jumping The Rifle Likely?.   His analysis is rather crude, to do it correctly would probably require computer modeling, but that is not what I want to talk about today.   Harrison's model estimates the stress on the bullet due to the rifling is 18,200 psi, and he concludes: this value is within the compressive strength of even moderately alloyed lead.    That is a false statement.   In reality, even hard lead alloys like linotype have only about 10,000 psi strength.   

Page 16 seems to explain where the good Colonel got the false impression that lead is stronger than 18,000 psi.   He says: Brinell hardness numbers express compressive strength in kilograms per square millimeter (each number then corresponds to about 1420 psi).   Once again, this is false, or at least it is half false.    It is true that BHN is a certain measure of kilograms over square millimeters, but that should not be confused with strength.    Even though they have the same units, BHN and strength are different tests that give different results and mean different things.  They do correlate, but the correlation is strength = 500 X BHN, not 1422 X BHN as the Colonel suggests.   

So the Colonel may be the original source of the 1422X fable?    The fable is sometimes attributed to to Richard Lee or to Veral Smith, but Harrison's article was published around 1963, long before Lee or Smith published anything.   In any event I agree with Harrison that hard bullets are good.   :fire

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Brodie posted this 09 August 2015

Congratulations MtnGun;  You have proven once again that one of our members was not perfect in 1963.  It should be a mark for  all of us to watch ourselves and  be careful that we not make an error when postulating about what goes on between bullet and bore when the shot is fired.  Especially if we do not have the equipment time or where with all to do the proper physics experiments before we dare to post any ideas.  I suppose that next you will decide to tackle Steven Hawkings with your towering intellect.  You have done nobody any favors except to let us know that writing down any idea leaves us open to inspection and ridicule by at least some of the membership.  Brodie

B.E.Brickey

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mtngun posted this 09 August 2015

Old Coot, I am an admirer of Colonel Harrison, and I agree with 90% of his conclusions.   I think his work was amazing for his era.   Yes, he got a few things wrong, but still he got a lot right.   He was a pioneer.    I learned a lot from him.

Ditto Harold Vaughn, Veral Smith, Richard Lee, Dr. Mann, Harry Pope, Elmer Keith, Tom Gray, etc..  They were all pioneers who questioned conventional wisdom and advanced our hobby in the process.   I study them all and think about what they say.   Sometimes I agree with them, sometimes I question them.   It's called “critical thinking.”    I was under the impression that critical thinking was a good thing, but I guess it depends on your values?    

The point of my post was that I found the Colonel's comments on bullet alloys interesting, relevant, and thought provoking.     Isn't that what the CBA was supposed to be about?        The irony is that if Colonel Harrison were alive today, posting on the CBA forum and debunking conventional wisdom as he did back in the 60's, you would be offended by him, just as you are offended by me.    I suggest you think about that.   

As for making errors, I make errors and false assumptions all the time.   I change my mind all the time as I learn more.     That's what makes it interesting!    If I ever get cast bullets completely figured out, I would be bored with it and would have to find another hobby.  :P Why can't we discuss cast bullets without making it personal?

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Brodie posted this 09 August 2015

Maybe you should re-read your first post from the standpoint of someone who is not fully aware of your admiration for the man.  It comes across as a gleeful attack on someone who was working in the area and made an error.  That was my objection to your post and continues to be.  You left out all background and posted only on the errors you found.  I think that if we were to look at IZac Newtons early work before he polished it As far as being personal :P  Your started it.  I pointed it out in the same personal way you did. Brodie

B.E.Brickey

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JeffinNZ posted this 09 August 2015

The tone of this discussion 'gentlemen' is why other forums have fallen over. Play nicely please.

Cheers from New Zealand

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John Alexander posted this 09 August 2015 

      Different posts strike each of us in different ways depending on our backgrounds, personalities, and maybe how things went at work that day.  Mtngun's original post didn't strike me as a personal attack or as disrespectful of Col. Harrison and his work, but then I have a thick skin when folks disagree with my own writing ”€œ as long as it is based on evidence and not just on what some guru has written.  I understand that others may see things differently.  

    I didn't know Harrison but from his writing I suspect that he would have welcomed corrections to his work based on evidence ”€œ as we all should.     I have stated before that if we are to learn how to shoot CBs better and improve our understanding of the basic principles involved, we need to challenge the conventional wisdom, not with opinions based on theory but with test results and evidence. This should be done politely and carefully and without denigrating others but we shouldn't shy away from pointing out that some of the long repeated advice about cast bullets just isn't true. I hope this forum provides and encourages just that type of exchange.   Misinformation no matter how many times it appears in print is a disservice, especially to shooters just getting interested in cast bullets.   It misleads, waste their time and energy, and may drive them away form a great hobby.   John  

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mtngun posted this 09 August 2015

I started it? When did I start a personal attack on you or any other current CBA member?

Yes, I left out “all background” because my post did not pretend to be a review of the entire book.

But since you brought it up ..... as I was re-reading the book I kept thinking to myself “man, Harrison was really GOOD! Especially considering what he had to work with -- no internet, no CBA, no nothing. He was a GIANT in his field."

I was particularly delighted to discover the Harrison footnote recommending hard bullets even for light loads. Harrison had it figured out 50 years ago!

I have several points of disagreement with Harrison, like his insistence that sizing hurts bullets, that molds should not drop oversize bullets, and that 30 caliber bullets are best sized 0.308". Even on those points, I can put myself in his shoes and understand where he was coming from -- he was using unmodified Lyman sizing dies, which are definitely capable of sizing bullets off center. I myself don't like to size more than 0.001” in a base-first lubrisizer. Push-thru dies are another story.

In general, my main complaint about Harrison is that he published his conclusions and recommendations but rarely published the shooting data that led to those conclusions. From my point of view, bearing in mind that I am an engineer and that engineers are trained to be skeptical of technical claims, the scarcity of data comes across poorly. Having said that, I suspect that Harrison made his data available to the editor and the editor chose not to publish it, because nerdy data does not sell books and magazines.

I could go on and on about CB superstars who I admire and yet at the same time I openly question them on certain points. That's just my nature, for better or worse.

BTW, since you mentioned Issac Newton, yes Newton was a character on a personal level, hard to get along with, and he had his share of crackpot ideas that were proven untrue. Those things are duly noted in the history books yet Newton is still very much a giant.

One of my favorite quotes is by Newton, “If I have seen further, it is by standing on the shoulders of giants.” That applies to cast bullets, too!

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Brodie posted this 09 August 2015

MtnGun,  Please accept my apologies.  I jumped the gun so to speak, and as John put it :  “Things didn't go so well at work."  .  Even though I am retired.  Perhaps we can all learn from this.

I am unfamiliar with Col. Harrison's work.  Never read his book.  I am quite impressed that you could find the errors.  I would not be able to.

Again, I am sorry for ripping into you.  It was not my place to do so. Brodie

B.E.Brickey

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mtngun posted this 09 August 2015

Thanks much for the apology, Old Coot.   I have a thick skin and try not to take CB-related debates personally.

Even though I gave Harrison a hard time on a few points, I cannot overstate how much I admire the Colonel's work.    If I had been in his shoes in that time and place, I could not have done as good a job as he did.   He was waaaay ahead of his time, a true pioneer in what was then a wilderness.    I found myself agreeing with his conclusions 90% of the time.     Today we have better lubes, we have the Ardito sizing system, we have push-thru sizing dies, we have heat treated bullets, and we have gobs of mold options that Harrison could only dream about.   But other than that, Harrison pretty much had it figured out 50 years ago and he was glad to share his knowledge instead of keeping it close to his vest as some people seem to do.

Also, when you read the Colonel's articles, which were originally published in the American Rifleman, and then you compare it to what today's NRA publishes, it makes you wonder what the heck happened to the NRA?     Even the letters to the editor were of better quality in those days.  :D :D :D

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Ed Harris posted this 09 August 2015

I was lucky to have been mentored by Col. Harrison and worked closely with him on the NRA staff, as did also Bob Sears. He was old school Army, West Point Class of 1924, and originally trained as an artillery officer. During WW2 many later NRA staff members served under him in the ETO, among the name who will be familiar to you were Malden D. Waite, former Technical Editor of American Rifleman, Ludwig Olson and William C. Davis, Jr. All former Army Ordnance Corps.

Col. Harrison went on to get his PhD in engineering mechanics from MIT and was one of the pioneers on the Army's Redstone missile program and worked with former German scientists on the ballistic missile programs before they were turned over to the Air Force.

After he retired from NRA Bob Sears and I visited him frequently at his Arlington, VA home, and enjoyed frequent range trips where he continued his cast bullet experiments.

The 1422xBHN approximation I believe did originate with Col. Harrison, but is often used out of proper context, because he clearly understood the differences between compressive strength and shear strength, and also the effects of Sb-Sn intermetallic compounds and grain structure upon the mechanical properties of lead alloys.

Dennis Marshall was probably the first to explain these factors in plain language, backed up by his experience as a materials scientist for Johnson Controls battery division, where he worked on a daily basis in the lab with the mechanical and physical properties of lead alloys.

After the American Rifleman magazine was taken over by ad salesmen and marketing people with no engineering experience, the value of back issues as reference material rapidly declined. I find little of value published after the time I left in 1984.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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mtngun posted this 09 August 2015

Thanks for the info, Ed.   I wasn't aware that the Colonel had an engineering background, but that would explain his methodical approach.   Apparently he compiled a lot of data during his experiments -- he showed a picture of his filing system that he seemed quite proud of -- and it's a shame most of it was never published.   

Dennis Marshall's articles were awesome, too.   I needed to refer to one of them just yesterday for a project I was working on.   I don't think Dennis invented heat treating lead alloys, I seem to remember reading somewhere that Germany developed the technique for making battery plates during WWII.   But as far as I know Dennis was the first to bring it to the attention of American casters like me, and it made a huge impact.   Used wheelweights used to be considered junk, now it is highly sought after.   

At the risk of beating this horse to death, the rule of thumb -- in the absence of data to the contrary -- is that compressive strength is the same as tensile strength for ductile metals which would include most bullet alloys.    Yes, shear strength is different than tensile/compressive strength and shear strength is what the Colonel should have used for estimating the bullets ability to resist “stripping.”    In defense of the Colonel's sloppiness on strength, even today with the help of the internet it is tough to find verified strength data for lead alloys.   

What little laboratory data available is usually for solders, but it gives you a feel for what it might be like for bullet alloys.  Our hard bullets might be 2 or 3 times as strong as 10:1 solder, but that's still not very strong.      I found the following chart at http://www.metallurgy.nist.gov/solder/NIST_LeadfreeSolder_v4.pdf>this link.   http://www.efunda.com/materials/solders/tin_lead.cfm>another source for solder strength, if you don't mind converting it to PSI.

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TRKakaCatWhisperer posted this 09 August 2015

I listen to half the arguments - those that delimit 'here is how it worked for me...'

Moving on, do y'all have a table of tensile and shear strengths for common lead-free solders?

AND related to that, what are the dangers of shooting near-pure tin bullets? Do they include “soldering or tinning” the bore?

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mtngun posted this 10 August 2015

TRK, I dunno if you are being facetious, but there is info on lead free solders at the first link I posted in #11.   I haven't tried shooting tin bullets, but they might pose a danger to my wallet.  :D . "How it works for me” always carries more weight than armchair theory.   . Last I heard the majority of serious CBA competitors were using hard bullets regardless of the load PSI -- just as Colonel Harrison recommended 50 years ago.

To sum up my own experiences with bullet alloys, I have never, ever had best results with soft bullets in magnum revolver loads or even low pressure 1400 - 1800 fps rifle loads.    Sometimes I have had perfectly satisfactory results with medium hard bullets, like wheelweight/lino blends.    They didn't shoot better than pure lino, but they shot just as well (or at least I couldn't detect a difference),  cost less than pure lino, and the denser, more ductile bullets  had more knockdown effect on steel rams, compared to pure lino.    

I gradually became more comfortable with heat treated wheelweight and currently use it for everything other than black powder.    But for a long time I continued to shoot medium hard bullets in some guns because I had a pet load worked up for a particular alloy and if it ain't broke, don't fix it.    

I also ran into problems, back in the 80's, with heat treated 170 gr. 7mm bullets becoming banana shaped and/or their noses getting unintentionally bumped up while sizing in a lubrisizer prior to oven treating.   So for a while I gave up on heat treated WW in the 7mm and continued to use a medium hard alloy instead.  Its accuracy was great for my 1400 - 1600 fps loads and it was hard enough to resist “bumping up” or bending in the lubriszer. 

After I was introduced to push-thru sizing, I could size air-cooled WW without bumping up the nose or bending long skinny bullets, so I no longer had any reason to not use heat treated WW.

Because of its cost, I haven't done a lot of work with pure lino bullets.   While we can certainly make WW just as hard or harder than lino, I'm curious if lino may nonethless have some advantage on paper targets due to its lower density?    

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mtngun posted this 10 August 2015

I should add that early in my casting career, like many casters I found it challenging to get good fill with wheelweight in some molds.

As my casting skills have improved I've become more comfortable casting with wheelweight and rarely feel the need to add tin to improve fill.

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TRKakaCatWhisperer posted this 11 August 2015

mtngun wrote: TRK, I dunno if you are being facetious, but there is info on lead free solders at the first link I posted in #11.   I haven't tried shooting tin bullets, but they might pose a danger to my wallet.  :D . ...   I was being straight up.  (I missed the link in the fine print - old eyes or laziness.)  Thanks, it's got a wealth of info.

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