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and deep gouges that can weaken the case wall, also any gouges in the case neck.
The next step is to resize the case. We first need to work on our resizing die. When you resize a case the die squeeze the neck down more than necessary, then the expander ball expands the neck to the correct diameter. The problem is that the expander ball can pull the case neck out of true. Take the die apart, look at the expander ball. You will see that it has a gentle sloping front edge, a flat edge, and a sharp slope on the top of the expander ball. It's this sharp edge on the top of the expander ball that can catch the case neck an pull it cockeyed. If your die has a removable expander ball, your in luck. Just turn the expander ball over. This will put the gentle slope pointing away from the decapping pin. This will allow the expander ball to enter the reduce sized case neck and gently open up the neck to the correct diameter.
If your die doesn't have a removable expander ball, you will have to put a gentle sloping edge on the top of expander ball yourself. Take the stem of the decapping rod and chuck it in a drill. With a fine stone and the drill on medium speed, slowly work the top edge of the expander ball over the stone. Carefully shape a gentle slope to the top edge just like the bottom edge. Work carefully, DO NOT reduce the diameter of the expander ball. You need the full diameter of the ball to open up the case neck to the proper diameter.
With the modified die in hand, you need to add a rubber O-ring around the die body. This O-ring will be sandwich between the die locking ring and the press. This allows the die to center itself in the press. Before we go any farther, make one modification to the press. If the press holds it's shell holder with a spring clip, you need to remove this clip. Insert your shell holder in the ram, and use a rubber band to hold it in place. The rubber band allows the shell holder to center itself as the case inters the die.
Were ready to adjust the resizing die. This is where most people get it wrong. They raise the press's ram to its full height and screw in the resizing die until it touches the shell holder. Over the years I've had only one rifle that the correct setting was with the resizing die touching the shell holder. The only way to accurately set your resizing die is to use a head space gauge. By using the RCBS precision mic. Or a Stoney Point head space gauge, you can achieve the correct cartridge to chamber fit that will give the best accuracy and extend the life of your brass. I'll talk about the precision mic. Because I'm familiar with it. If you measure 10 to 20 cases with the precision mic. You will get an average reading between 0 to -.001. This is as it should be. New cases from the factory have to fit all rifle in that caliber. Our goal is to fit the case to our chamber.
With new cases we want to set the resizing die to neck size the brass. (DO NOT set back the shoulders of the cases) Our goal is to make the necks round and to get uniform neck tension. With once fired brass that was NOT fired from YOUR rifle. You must full length resize the brass to factory dimensions. (0 on the precision mic., shell holder touching the die) Load your cases as described below, then fire them in your rifle.
With 20 cases that was fired in your rifle, we can use the precision mic. to determine the average measurement on the gauge. For example my brass measured 0 on the precision mic. , when fired in my rifle it will measure about +15 on the precision mic.. This means that when the case expanded to fill the chamber, the shoulder was pushed forward .015". (fifteen thousandths) This is a average measurement of your brass that was fired in your rifle. Write this average down in your reloading notes.
If your reloading for a bolt action rifle take the average measurement of the fired case and subtract .002 to .003 thousandths off the average. If it's a pump, lever action, or semi-automatic you will need to subtract .004 to .006 thousandths from the cases average measurement. For example my rifle a M-1A (semi-auto) fired cases measure +15 on a precision mic. so I subtract .005 thousandths (.015-.005= .010) My cases will read +10 on
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