BS-Relationship between accuracy, BHN and pressure

  • Last Post 12 August 2018
joeb33050 posted this 11 August 2018


Relationship between accuracy, BHN and pressure


Cast bullets must be harder as velocity increases, else leading. Kinda.


Is has been written that there is a mathematical relationship between accuracy, BHN, and pressure. This has been disproved several times. (“CAST BULLETS FOR BEGINNER AND EXPERT”, Third Edition, Appendix, 3.3 BULLET HARDNESS, CHAMBER PRESSURE AND ACCURACY).


The myth lingers on. And even if it were true, we cannot, at home, measure either pressure or BHN with any accuracy. I hope to hear from Ed Harris on this; he and W. Davis authored the seminal article.


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Larry Gibson posted this 12 August 2018

This is indeed a myth.  I measure pressures and have, can disprove it anytime.


Concealment is not cover.........

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Geargnasher posted this 12 August 2018

Yep, it's not that simple. If velocity, bhn, and and pressure are held constant, changing bore size or ROT will likely require a change of one or more of the three to achieve the same accuracy.

Further, bhn 22 achieved from linotype will shoot differently than hardened #2 alloy which will shoot differently than hardened wheel weights or reclaimed shot.....all as the same "hardness" via the indentation Brinell test.

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