A Case for Weight-Sorting Your Cartridge Brass

An old friend of mine had a terrific custom .30-06 rifle built. He chose top-shelf components and had it built by a gunsmith who really knows his craft. The rifle wouldn’t shoot. It wanted to, but it regularly threw fliers that opened up tiny groups.

After several unsatisfying range sessions, he contacted me. We headed to the range together for a little accuracy therapy session to see if we could determine the issue.

While observing my friend at the bench, watching for signs of human-induced inconsistencies, I checked out a few rounds from his box of handloads. All the signs indicated he was doing everything right—until I looked at the cases’ headstamps. In the five or six cartridges I held, there were three different stamps: Winchester, Remington and Hornady.

When he’d finished shooting a group and set the rifle in the shade to cool, I asked, “Did you get a couple of batches of handloads mixed together recently? I found several different makes of brass in that box.”

“Nope,” he responded cheerfully. “I just load all my cases together.”

I sorted through his handloads, picked out three with identical Winchester headstamps and asked him to shoot a group with them. Two bullets landed almost touching. The third turned the snake eyes into a perfect, half-m.o.a. cloverleaf.

Sorting cartridge cases by manufacturer and lot is a small but significant step in achieving consistent handloads. I do my best to keep cases in batches with an equal number of firings. Once past four or five loadings, I set batches aside for practice. That way, I’m less likely to experience an unexpected crack at the neck or around the web near the case base—or worse, a case-head rupture.

Avoiding mixing cases with various numbers of reloaded/fired cycles on them also enables me to sort effectively by weight. When striving for ultimate accuracy, weight-sorting is worth the time. Cartridge cases are mass-produced. In any product that’s generated in the hundreds of thousands, there will be anomalies. Sorting by weight helps eliminate cases with inconsistencies.

The higher-quality your cases are, the less important weight-sorting is. For example, if you purchase new brass made by Lapua, Nosler or Norma, weight-sorting is basically a waste of time because their quality control eliminates significant anomalies. Where you’ll make a difference is with the standard stuff—Remington, Winchester, Hornady, Federal and so on.

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Weight-sort early in a case’s lifespan. Why? Because every time a cartridge case is fired, it stretches and thins. Brass flows forward from the shoulder area into the neck, and the entire neck flows forward as well. Even if you trim only every other reloading, you’ll remove a certain amount of material each time you trim, effectively making the case lighter.

Plus, deep inside, brass flows and thins around the case base. Handloads at the upper pressure spectrum are particularly prone to this.

If planning to weight-sort a batch of cases, I generally do so after the first firing. I load and shoot the entire batch once, then resize and trim to length. If I’m going to neck-turn the cases, I chamfer the inside of the case necks and then do so. Finally, I debur the outside edge of the case mouths, then set about sorting by weight.

I use an electronic scale, which I calibrate before starting. I use a big sheet of paper, such as drafting or artist's paper, and once I have a handle on the average weight of the cases I’m working with, I write a scale across the close edge. To get started, I quickly weigh 10 or so cases to get an average, and pencil that in. I then create a scale moving in small increments right and left of center.

If weighing big cartridge cases like the .300 PRC, I mark the scale in half-grain increments. If working with small cases such as the .223 Rem., I mark the scale in much smaller increments—generally 0.2 grain.

As you work your way through a big batch of cases, you’ll find that most of them clump together in the middle of your weight range. With big cartridge cases, a “batch spread” of one or even two grains is acceptable. With medium and small cases, say from the 6.5 Creedmoor down, I tend to sort batches in one-grain allotments.

I generally keep a small cardboard box behind center, and I regularly shift the weighed cases from the ranks building front and center on my paper into the box.

A smaller but still significant percentage generally falls just above or just below the average weight. Those can usually be allotted into their own category of 20- or 50-count batches, particularly if you’re doing large quantities of cases.

On each side of the spectrum, you’ll find above-average and below-average weights stringing out. Depending on how many cases you’re sorting, there may be two or three on each side, or there may be 20 or 30. And sometimes the variation is extreme. I’ve seen 6.5 Creedmoor cases as much as five to seven grains above or below average. That clearly indicates some internal anomaly—the sort that can cause an accuracy discrepancy.

What do you do with all the outliers? If you’re rich, you can simply throw them into the recycling bin. However, the most practical thing to do is set them aside for close-range practice from field-type shooting positions.

A couple of days after shooting with my friend, we took a fresh batch of handloads to the range. This time, they were assembled using weight-sorted cases of the same make. He put three Hornady 168-grain ELD Match bullets into a 3/8th-inch group at 200 yards.

“Jiminy Cricket!” he said in delight. “This rifle really shoots.”