Fireformed Cases

        These four cases were fired in my rifles.   I etched a label on each case showing which rifle it was fired in, and I keep them separate from my other brass.   These fireformed cases are exactly the same dimension as the particular chamber from each rifle.   (20,000 to 50,000 psi chamber pressure ensured that.)

        These fireformed cases are now helpful tools when I need to see how my handloads fit in my chamber.   I use them to help measure the "exact" chamber clearance that my handloads will have in each of my rifles.

        The closer you make your handloads to your chamber size, the less your brass will stretch and the longer your cases will last.   You'll also get better accuracy.

        I start by measuring one of these fireformed cases with my Digital Headspace Gauge, then I zero the gauge.   Then I measure my handloads, and the gauge displays the exact chamber clearance for that particular rifle.   I have (3) different rifles chambered for .308 Winchester, and each one has a chamber that's slightly different from the others.

        I can make my handloads fit all of those rifles by making them fit the smallest .308 Win. chamber, or I can make my handloads to tighter tolerances (for best accuracy), and build them specifically for each rifle.

        Setting your resizing die height to "bump your shellholder" will almost always make your handloads have too much chamber clearance.   This is usually more serious on belted magnum and rimmed calibers, and it can result in case head separation.

        Quite often shooters find that their handloads won't chamber without using force.   This measuring technique clearly shows you why your handloads don't fit properly.   The problem can be headspace length or excessive case width.