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View Full Version : What is the hardness of the lead core inside a jacketed bullets



Bigoledude
11-23-2010, 06:37 AM
I often read here about jacketed bullets failing. If the jacket peels off prematurely upon impact with my targeted animal, what is this material inside the jacket and, what is the typical hardness of this core material?

Is it wrong to aassume I now have the same thing as a cast bullet?

curator
11-23-2010, 07:16 AM
Core material varies with the original manufacturer but is usually close to pure lead with 1-3% antimony. These days I rarely seperate jacketed bullets when smelting but when I did small batches I found it to be very similar to scrap .22 rimfire lead. Not quite as hard as wheel weight alloy and needing a bit of tin to cast well.

Bret4207
11-23-2010, 07:19 AM
Most of the core material is reported to be very soft lead alloy, often stated to be "pure lead". I don't know for sure but the bonded bullets probably use a lead /tin alloy since it solders a lot easier than straight lead.

Just remember the faster you push a bullet or boolit and the more you ask of it (heavier game/south to north shots/shooting through brush) the greater the chance for failure. My bullet failure has centered around doing too much damage even at lower speeds or doing nothing at all. A simple FN cast boolit does what I need and is very predictable.

243winxb
11-23-2010, 10:04 AM
Is it wrong to aassume I now have the same thing as a cast bullet?
If the core is separated from the Jacket, most cast alloys will be harder, if heat treated, cast bullets will also be harder. Cores are pure to 2% antimony. Jackets are 95 % copper & 5% zinc. The jacket can be thicker in some areas. The nose/ogive can have small cuts/slits in it to aid controled expanding. Some J bullets have the core added as molten metal , like solder. There is a patented bonding process when the copper jacket is bead blasted inside, so the lead can be "bonded" to the jacket better.

Rocky Raab
11-23-2010, 11:38 AM
A true and clean separation of jacket and core is pretty rare, I think. More common is a partial ejection of core, with the remainder clinging to the ruptured jacket. In a classic "mushroomed" bullet, you can see where lead core has scraped or sloughed off what remains. The reduced weight of the expended bullet tells you just how much core was lost. The loss is usually in the form of small fragments as small as dust.

A full separation would have the effect of a misshapen cast bullet, yes. The result would not be much different from a roundball of pure lead, I'd assume. As John Barsness has recently written, full expansion is not a gradual thing. Bullets probably have fully expanded within their own length after entry. It is what happens after that that matters: deep penetration due to small frontal area, shallow penetration due to large frontal area, or almost no penetration due to bullet fragmentation.

mpmarty
11-23-2010, 01:49 PM
A given weight bullet at at speed possesses X amount of energy (kinetic) and can spend that energy by destroying what it hit or it can spend it destroying itself (expanding). There aint no free lunch.

kawalekm
11-23-2010, 01:59 PM
Core seperation is not necessarily the end of the world though. One of the first loads I developed for my 7mm used Speer's 130 grain softpoint. I tested this in wet newsprint and I could get clean core separation (in paper) at 7mm mag velocities.

This same bullet gave me a DRT kill on a deer I shot with it. Don't have a bullet to show though because I got 100% penetration. So, did the core separate? Most likely no, because there was just one exit hole. The standard joke of the bullet companies is that they have stacks of complain mail about their bullet retrieved from the DEAD animal that didn't perform perfectly, but, the animal was still DEAD, right!

markinalpine
11-23-2010, 03:50 PM
If you'll click on the Lead & Brass Logo, a CastBoolets board sponsor, and select one of their recovered range lead products, they describe it as "The result is lead alloy which is about 2% antimony and a minor amount of tin, usually .1 to .2 percent. The tested BHN of the resulting alloy is typically around 6.5 to 7 BHN." I expect that is typical.
Mark :coffeecom

Harter66
11-23-2010, 04:23 PM
I've about 200# of core ingots that using the pencil method run from 7-12 and will water drop to 15+-bhn.

I don't believe a j-bullet unless completely out of its coat is anything like a cast boolit.

1 must keep in mind that WE fought many wars ,defended 1000s of lives,and harvested millions upon millions of head of game from cottontail to elephant with little more than a soft lead ball from a smooth bore.

Black_Talon
11-28-2010, 11:29 AM
I worked for Sierra Bullets from 1978 to 1990. We used three different types of lead; Pure, 1.5% antimony and 3% antimony.

*In general* most rifle bullets used 3% and 1.5% lead. The smaller caliber HP and SP hunting bullets tended to get the 1.5% lead. The Match Kings used 3% lead.

*In general* the HP and SP pistol bullets used pure lead. *In general* the FMJ and FPJ pistol bullets used 1.5% or 3%.