From njohnson@nosc.mil Norman F. Johnson

Joseph,

I have had similar experiences. I recently got back into casting after a few years of inactivity. I batch of bullets I had cast years ago from wheel-weights registered a 10LHT. My recent castings were tested after cooling and again a few weeks later. The 5LHT bullets had increased to 7-8 and the 3LHT bullets had increased to 4-5. Does anyone have info on why this happens, or more importantly, how to predict the amount of hardening for a given alloy.

Common BHN measurements:

Pure lead, 5 BHN

Wheel weights, 8-13 BHN, composition varies

Lead/linotype, half and half, 15 BHN

Linotype, 22 BHN

40-1 Lead-tin, 8.5 BHN

30-1 Lead-tin, 9 BHN

20-1 Lead-tin, 10 BHN

16-1 Lead-tin, 11 BHN

10-1 Lead-tin, 11.5 BHN

Lyman No. 2, 15 BHN

Heat treated wheel-weights, 25-35 BHN, varies with heat treat and age

After 6 weeks, air cooled bullets will reach maximum hardness. This hardness can be further increased by heat treating.

The 1991 Jan-Feb issue of the Fouling Shot has an article by O.H. McKagen and Dennis Marshall entitled "On Lead-Tin Solders", page 89-8 through 89-14. It is the best explanation of bullet alloys, their hardening, softening, time dependent characteristics (no, that bullet that you cast last week is not the same bullet that you have on your shelf today) that I have ever read. It puts into perspective the nature of a number of alloys used for cast/swaged bullets, time hardening, time softening, boundary slippage etc., in words that the layman an understand.

The resulting knowledge can be used to give the caster/swager more control over his bullets than he might have ever dreamed was possible. It also helps one to recognize errors that often appear in the glossy gun magazines when the writers presume to relate their infinite wisdom to those (us) serfs who are unread, unwashed -- you know the rest.

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ANOTHER CBA PITCH

There are a good many articles in the pages of the official journal of The Cast Bullet Association that correct many of these old errors. Cast Bullet Association

Ralland Fortier

4103 Foxcraft Drive

Traverse City, Mich. 49684

$14.00/yr.

Back issues, Index, etc. from:

Frank Stanard, Director of Services

7418 Ridgewood Avenue

Chevy Chase, MD 20815

God Bless!

Norm