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Naphtali
05-28-2011, 01:19 PM
I have been casting with certified 30:1 for the special conical bullet for my .72-caliber muzzleloaders with superb results on which I'm not going to elaborate in this query. I thought my table for Brinnell range for lead:tin alloys was accurate. I find that our LBT and Log Cabin testers are giving significantly different (lower) Brinnell readings on bullets AND ingots than my table identifies.

I ask for the following information "just in case" I am able to afford an African hunt (for which I am saving) that would include Cape Buffalo. My bullet fits all of my 72s so well that bumping up bullet's base upon firing is not an issue. Therefore harder alloys that drop within parameters I ask about will shoot as consistently as 30:1. And I am not thinking of migrating to such a wastefully expensive bullet alloy for general shooting, for 30:1 does exactly what it's intended to do - except, perhaps, penetrate large support bones on Cape Buffalo. I guess I'm attempting to identify whether there is a lead:tin alloy that will not render a Cape Buffalo "dead but ambulatory" when hitting scapula or femur or pelvic girdle or other bone groups required for four-legged quick movement.

Assuming such an alloy exists, I would verify using the logical pattern: If A equals B, and B equals C, then A equals C.

That is, if a 458 Winchester Magnum 500-grain solid penetrates my plank-and dry newsprint bullet box a [fill in the blank] amount with no keyholing or direction change during passage through the test media, and this specific load is known (as it is) to be adequate and acceptable for breaking major bone groups of Cape Buffalo, then a .72-caliber bullet that penetrates the same distance in same bullet box and media without keyholing or changing direction will be functionally equivalent. . . . Whew! Long way around the concept or what?

1. Were I to use 20:1 what will Brinnell range be?

2. Would this alloy drop from my mold with a variance - from .731 inch I drop with 30:1 - of more than ± .0007 inch?

3. Were I to use 10:1 what will Brinnell range be?

4. Would this alloy drop from my mold with a variance - from .731 inch I drop with 30:1 - of more than ± .0007 inch?

ColColt
05-28-2011, 02:18 PM
1. Were I to use 20:1 what will Brinnell range be?

2. Would this alloy drop from my mold with a variance - from .731 inch I drop with 30:1 - of more than ± .0007 inch?

3. Were I to use 10:1 what will Brinnell range be?

4. Would this alloy drop from my mold with a variance - from .731 inch I drop with 30:1 - of more than ± .0007 inch?

I can answer #1 and #3 for you. 20:1 has a BHN 10 value and 10:1 has a BHN of about 11.5. In general, a softer boolit will be heavier but smaller in diameter than a harder one.
http://www.lasc.us/CastBulletNotes.htm

Naphtali
05-28-2011, 02:34 PM
I can answer #1 and #3 for you. 20:1 has a BHN 10 value and 10:1 has a BHN of about 11.5. In general, a softer boolit will be heavier but smaller in diameter than a harder one.
http://www.lasc.us/CastBulletNotes.htmYou identified the table I had been using. Our testers indicate much lower Brinnell range for 30:1 - about 6-6.5. And, unfortunately, the Brinnell readings we obtained matched the Brinnell range derived from a table I think was included with Cabin Tree's, maybe LBT's tester. My shooting partner is out of town, so I am unable to confirm which tester included the table. I think I remember that one of the testers read "55-57" which translated to the Brinnell range.

You are correct that softer lead alloys - that is, higher percentage of lead - nearly always are heavier. I suspect the differences among the lead:tin alloys I ask about will be less than 10 grains, probably much less.

cajun shooter
05-28-2011, 11:09 PM
The Cabine Tree Chart gives 30-1 a BHN of 9 and 20-1 is a 10BHN. I shoot 100% BP so my alloy is 20-1 with great results. The Cabine Tree chart gives new WW's a BHN 12.5 which I have never seen in Louisiana. The WW's here are in the 9 BHN area. Lyman #2 which is the old standard is given a BHN of 15 by Cabin tree.
If you look at the stickes it is there or go to Gussy who makes the Cabin Tree tester and is a forum member.

fredj338
05-30-2011, 12:40 PM
As far as bullet testing, forget the dry paper/wood medium, has little to do with how a bullet will actually perform on flesh & bone. While you can extrapolate some thoughts between bullet A & B, it doesn't mean you'll get C in the field. CLosest thing I have found for bullet testing & actual field use is wet pack paper. You can put a large cow bone 2-3" inside & shoot it dead center. That will give you some idea of how your bullet will actually perform on flesh & bone. Lead bullets too hard will fracture on hitting bone, too soft, you don't get the penetration you want as the bullets expand pretty quickly on the heavy muscle & hide, especially if the hide is wet. I would think w/ a lead bullet, hard & ductile would work better than hard & brittle. It just depends on the vel.
A buff has thick hide & heavy bone. Here is a bonded bullet that came out of one of mine, hit one rib going in. Impact vel about 2150fps. Bullet on left is wetpack, right is cape buff. Penetration in wetapck was about 19". The one from the buff went in slightly quartering away & was balled up under the hide near the shoulder, maybe nicking the blade of the off shoulder.
http://img.photobucket.com/albums/v703/fredj338/DSCN0552.jpg