Segregating Cases by Weight

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This is a specially-adapted excerpt from the forthcoming book, “Top Grade Ammo,” by author Glen Zediker, owner of Zediker Publishing. Click here to order from Midsouth.

by Glen Zediker

Weight is another common means of case segregation. I can’t imagine doing this job without an electronic scale, because I have done this job without an electronic scale.

A bag full of new brass is a wonderful thing. Sorting is optional, but worthwhile to get the very most from it.
A bag full of new brass is a wonderful thing. Sorting is optional, but worthwhile to get the very most from it.

Most set a percentage tolerance for weight, not so much seeking identical weights. Otherwise, you’ll have to sort a lot of cases. The physically larger something is, the more variation can exist. 1% is pretty harsh; 1.5% is more reasonable; 2% is commonly used. You’ll figure out the viability of your segregation criteria after you go through a few dozen cases. If you have 10 piles, then the criteria might be too harsh. If you use a percentage, certainly then larger caliber cases will have a greater overall weight tolerance/variance than smaller ones. Think of it as: 1% in a 90-grain .223 is 0.90 grains, and in a .308 Win., it’s 1.7 grains, or about double.

No doubt — cost is the first segregation criteria. The author says components from Europe are better than domestically produced items. But at what cost. The author has used a lot of Norma and Lapua brass, and it’s extra-high-quality, which means low-tolerance/variance. It’s also soft and heavy. I’d be willing to spend for it, but I prefer to sort other brands that are more suitable for use in a repeating action of any type. Hours and hours of doing this showed me that Norma, for example, gives about 5% more “really good” cases compared to the domestic brand I favor.
No doubt — cost is the first segregation criteria. The author says components from Europe are better than domestically produced items. But at what cost. The author has used a lot of Norma and Lapua brass, and it’s extra-high-quality, which means low-tolerance/variance. It’s also soft and heavy. I’d be willing to spend for it, but I prefer to sort other brands that are more suitable for use in a repeating action of any type. Hours and hours of doing this showed me that Norma, for example, gives about 5% more “really good” cases compared to the domestic brand I favor.

This segregation method or means is nearly universally adhered to by NRA Long Range competitors. The belief is that weight reflects on case capacity: heavier cases, lower capacity; lighter cases, higher capacity; and, mostly, same-weight cases, same capacity. Most are not looking for “light” or “heavy,” just “the same.” There’s a correlation between wall thickness consistency and weight consistency, I’m sure, but it’s not direct.

Don’t confuse the ultimate results from an exercise in segregation. We will get what we look for, but that’s all we know for sure. No doubt, the combination of segregation by weight and wall thickness should result in the best of the best, but, dang, that might also result in a very small pile.

Important: Fully prep all the cases prior to weight segregation! The reason is a matter of reliability in the result. Primer pocket uniforming, length trimming, chamfering, and inside flash hole deburring all require removal of brass. The amounts will vary in each instance. I’ve collected and weighed enough shavings from prepping before and can tell you that, if you’re segregating by fine increments, you’re kidding yourself if you don’t follow this advice. The amount of brass removed does not at all directly reflect on the quality of a case because the areas where the weight is originating don’t influence the “overall” quality. But it can influence the scale. Which is the criteria, right?

Weight segregation is easy, but tedious. Establishing criteria limits (defining the contents of each pile) comes mostly from experience in checking examples of the stock being used. Just weigh as you go and label as you learn. Get some plastic containers and label them, after deciding on the range you’re sorting by, and toss the case into the appropriate bin when you pick it from the scale pan. Keep in mind that the goal is to find “light” “heavy” and “okay.” Most shooters I know who weight-segregate are looking for three piles and, of course, the occasional culls.
Weight segregation is easy, but tedious. Establishing criteria limits (defining the contents of each pile) comes mostly from experience in checking examples of the stock being used. Just weigh as you go and label as you learn. Get some plastic containers and label them, after deciding on the range you’re sorting by, and toss the case into the appropriate bin when you pick it from the scale pan. Keep in mind that the goal is to find “light” “heavy” and “okay.” Most shooters I know who weight-segregate are looking for three piles and, of course, the occasional culls.

The procedure used by most winning 1000-yard shooters is to segregate by weight and then outside-turn the case necks to make the neck walls consistent. Again, it ultimately will be a better test if the neck turning is done prior to weight segregation. At this point, however, we have done a lot of work.

So, looking back on the last article, which was segregating by neck wall thickness variations, here’s what I think: If most of your shooting is under 300 yards, go with neck-wall thickness. If you’re covering more real estate, I’d suggest sorting by weight. No doubt, a combination is the ultimate.

Since I focus on concentricity both before and after bullet seating, I can’t say any weight-segregated cases have outperformed my concentricity-selected ammo at 600 yards. I also know, from experience, that the cases I favor are demonstrably low in weight variation. For me, segregating by wall thickness makes more sense. I use the same brand/lot for 200, 300, and 600 yards; the difference is the load. I am pretty much looking for a good, better, best to coincide with my needs for accuracy at 200, 300, and 600 yards.

This might sound contradictory, but it seems that when firing on targets at short range, where weather conditions aren’t overly influential and bullet limits are not nearly being approached, it’s superior concentricity that prints the best groups. Further on down the pike, though, concentricity is important, certainly and always, but it’s really the consistency of bullet velocities that gets “10s.” A good long-range shooter (who can keep a handle on condition-influenced corrections) will lose more points to elevation shots than to wind. High-low shots are, for a Master or High Master, pretty much the fault of the ammo. The reason velocity deviations are just not that important to short-range groups is solely a time-of-flight answer. The longer a bullet is in the air, and the slower it’s moving, the farther and farther it flies, the more initial velocity consistency factors in.

The preceding is specially-adapted from material in the forthcoming book “Top Grade Ammo” coming (very soon) from Zediker Publishing. Check BuyZedikerBooks.com and ZedikerPublishing.com for more.

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8 thoughts on “Segregating Cases by Weight”

  1. Shouldn’t cases be measured in volume instead of weight. Volume will give you a more consistent value to judge by.

    1. Case volume is typically used to help the reloader determine which powder to use. Ideal powder case volume is typically between 80-90% of case capacity. The shooter can calculate how many grams of powder the case will hold by knowing how much water it will hold and select a recommended powder to fill the case to apporx. 85% full.

  2. I sort my competition brass by weight, but I use a different procedure. My Lapua brass is reasonably consistent but far from perfect. It’s also expensive, so I don’t want a pile of “OK” and two batches of “light” and “heavy” which don’t get used. I can’t justify buying expensive brass which just sits there. I have plenty of Lake City brass for plinking. And it seems to me that my testing should be done using ammo identical to my competition ammo, not some sub-set made out of reject components.

    I need 60 rounds for F/TR plus some sighters, so I take a batch of about 75 cases and sort them into light, medium, and heavy piles using weight criteria of about one half of one percent. I also sort my bullets by weight in a similar way, but even smaller weight differences. A 20 shot string, plus sighters, will be made from cases which are all from the light pile, the next 20 from the medium pile, and so-on.

    When I’m done, all my 75 rounds aren’t absolutely identical, but each cartridge in a particular 20 round string is as close to identical to the other 19 as possible with brass weight deviations of less than 0.5 grains.

    Lately I’ve been doing significantly better in my F/TR matches. Is it because of weight sorting brass/bullets? That’s hard to prove or disprove, but my procedure is easy, doesn’t result in any reject brass, and strikes me as a reasonable approach to making precision ammunition.

  3. It is Always a good idea. Here is how I do it. Buy in min. 100 round lots. Do ALL of your prepping before weighing the case itself. Weigh every case and segregate them in 1 grain increments. I have found as of late that some of the better brass in made by Hornady and some of the worst (to my dismay) has been Remington. This may vary but that has been my experience especially in 7 rem mag. Doing this you should be able to come up with 5 twenty round boxes that WILL shoot better than most rifles will. If you have the equipment and the time–why not?

    1. To add on this, once the one grain goal is done separate them by tenths of a grain. Also weigh the bullets in tenth of a grain increments. I actually mark all my cases with a sharpie so there are no mistakes at the range or in the field. Happy shooting. Send it.

  4. I just can’t get enough sorting. Between neck thickness and weight and concentricity ,etc. I can’t seem to find much trigger time

  5. I’ve sorted LC 5.56 brass by .1 grams increments before, doing enough to 10 rounds each of light, medium and heavy medium. They weren’t the lightest or heaviest in the group because you couldn’t get 10 of each without going through a lot of brass but they were close to the maximums. Then I loaded them with my regular load for XBR 8208 and 77 NCCs and chronographed the results. All the loads had similar velocities and the light and heavy group had lower SDs then the middle group; I’ve completed this exercise twice with similar results so my conclusion is I should weight all my brass and only use the stuff on either end of the spectrum.

  6. We’re not talking about big changes, most shooters wouldn’t even notice the difference, most shooters don’t care about a quarter of an inch at 100 yards or half an inch at 200. Unless you have a quality rifle with properly torqued screws and good optics you would be wasting your time weighing cases. There are many factors that contribute to an accurate hand load, but weighing cases is an important step before you can select the best powder and the best bullet for your firearm. Choosing bullets and powder is even more time consuming than complete case preparation, but it’s also more fun.

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