Watch Your Brass: A Guide to Cartridge Cases

A reader asks that I do a post on brass. Glad to. If cartridge brass didn’t exist, it would have to be invented. As a case material, it combines strength, elasticity, and reasonably low price. The only other option I know of is steel, which is used only in military ammo, and only by depressing Eastern-bloc countries, and must be given a “wash” of copper to keep from rusting.

So, brass it is. Cartridge cases are turned out in enormous numbers by means of forming dies and punches. To shoot accurately, they must be made with a high degree of precision and uniformity. Some brass is quite rotten in this respect. An ammo company whom I shall not name once sent me a box of 300 .416 Remington shells because I was unable to buy them and groveled for help. Out of that number, I was able to find perhaps 30 that were usable. The rest went in the fired-brass bucket at the range.

The case’s neck must hold the bullet in alignment with the center of the bore. It must also be round. Some brass has necks that are off center, and some that are bashed out of round. Running them through a sizing die will cure the bashed ones, but the off-center necks will probably remain off-center. You won’t know this until you shoot a flier for no apparent reason. That shell goes in the spent-brass bucket.

Necks must also be of uniform thickness for their entire circumference, and of the correct thickness. Shooters who are crazed about precision will often turn the necks down to the proper diameter. I don’t. This is because I’m lazy and I’ve found that if I use good brass it doesn’t matter.

Neck length is one thing you must pay attention to, because necks that have stretched too long can cause pressure excursions, which is an erudite way of saying they can blow primers or worse. I trim them back so they’re .05 to .10 shorter than max. For example, when reloading .308s, whose maximum length is 2.015, I cut them back to 2.005 to 2.010.

Good cases will weigh within a grain or two of one another. Some shooters are fanatics and segregate their brass into lots by weight. I don’t. I’m too lazy, and I’m probably not a good enough shot any more to take the time involved. Good brass, I’ve found, doesn’t vary enough to make the practice worthwhile.

Never, ever mix brands of brass. Some makes use thicker brass than others, which boosts pressures. If you work up a load with Brand X brass and then want to switch to Brand Y, you have to cut back your powder charge to the starting level when you do.

Primer pockets must be of the correct depth and of uniform depth, because this can affect primer ignition, which in turn influences how the powder charge burns. The flash hole is also crucial because that’s what lets the primer flame at the powder. Some flash holes are punched very crudely, and if you look on the inside of a new case, you’ll see tiny brass petals around the edge of the flash hole. Really dedicated handloaders go inside with a reamer and chamfer the edge of the flash hole so there’s nothing around it to impede the flame. I don’t. I’ve tried it and the practice didn’t seem to make any difference.

The primer pocket is your best indicator of when a case’s useful life is at an end. Every time you shoot, the pocket expands a little bit. Eventually, when you seat a primer, you’ll feel it seat with no resistance at all. I keep a felt tip marker at hand, and when this happens I paint the base of the shell and that’s the last time it gets used.

Here is my highly subjective evaluation of the brands I’ve used over the years.