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Custom Made Rifle Bullets - Hand Crafted in England
  Bonded Core Bullets        
Perhaps I should start out with what, exactly a bonded core bullet is, and why we take the trouble to do it. They are designed specificaly for hunting, the lead core of the bullet is chemically bonded to the copper alloy jacket so that it will hold together under the huge forces generated when the bullet strikes its target, and also help to provide "uniform expansion"!

This "uniform expansion", to me, is a misnomer! The bullet would have to strike in exactly the same place, at exactly the same angle and hit exactly the same things to be anything like "uniform"! Clearly, in a real world, this is unlikely to happen.

For me, the benefit of bonding the core to the jacket is that it really does help with holding the bullet together when it strikes. A bullet that holds together will retain more weight, have more kinetic energy and, as a consquence, do more damage, ensuring a quicker, cleaner kill. This is basic laws of physics.

I always carry out a basic "post mortem" when I shoot a deer, the angle the shot was taken from, entrance and exit wounds and the damged caused by the track of the bullet. This helps give me a better understanding of what I need to do at the other end of the ballistic curve, and also how the bullet has performed!

I've only been fortunate enough to recover two of my bonded core bullets, the rest went straight through! One was from a 200 lb whitetail deer, in Alberta and the second was from a 300 lb red deer in Scotland. The whitetail bullet had 82% weight retention and the red deer, 76%. These are not particulary spectacular numbers, but the damage they had caused was something else. Far more devastating that a normally contructed bullet.
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So, how is a bonded core bullet made?

The first step is to remove all traces of the lubricant used during the jacket making procedures, from inside and outside of the jacket. For this I use a specialist detergent which, in its turn, is difficult to remove, and takes copious amounts of water to remove.

Once the detergent has been removed the jackets have to be dried. The weight adjusted lead core's also have to be cleaned with the detergent and dried before the bonding process can be carried out.

Once the jackets and lead core's are clean and dry there is no more touching them with your skin! Even a very samll amount of the natural oils in your skin can ruin the bonding process.

The lead cores are coatd with a very specialist fluxing agent and placed in a jacket. These are then flash heated until the lead melts, and then allowed to cool. Once the lead has solidified, they can be dropped into a bicarbonate of soda bath to neutralise the acids contained in the flux. Washed to removed the bicarb, then cleaned again with the detergent, washed with water again, and again, and again to remove the detergent.

Once dried, the bullets can be progressed as per any other bullet, except...!
The bonding process can cause some problems. If there is an air bubble or void in the molten lead, when it cools, there is obviously no lead in that spot. The next stage of manufacture is to press the core into the jacket, and at the same time expand it to fill the die. The chemical bond between jacket and lead is so strong, quite often the jacket will get crushed into the void. If you have a look at the picture below, click on it for a larger version, you can see on the bullets this effect, in the lines around them.

In extreme cases, like the bullet on the right, as I tried to press the Lead in the jacket split all the way around! To give you a little understanding of how powerful the chemical bond is, internal die pressures vary from around 50 to 90000 PSi. The chemical bond is STRONG!
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