Weight Sorting 5.56mm Ammo

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There’s old-school rimfire lore that you can make any cheap box of loose, bulk, 22LR into “match grade” by weighing each bullet cartridge and sorting it by weight into batches. In theory this makes sense because “match grade” ammo differs from “normal” ammo in extra quality control more than construction. I decided to see if this was true? In my tests at 100yrds, I found that my weight sorted 22LR ammo formed 50% tighter groups than unsorted 22LR randomly pulled from the same box.

Which got me wondering, does the same sorting process work with centerfire ammo? I tested it out with a bulk ammo can of Winchester 5.56x45mm 55gr FJM “white box” that I bought at Bass Pro in 2019 before the pandemic and ammo shortage. Winchester White Box has always shot kinda oko in my Aero Precision 20″ Mil-Spec upper; reliable but meh. I usually to get a 3″-3.5″ group at 100yrds, bench rested.

I sorted out 50 cartridges that all fell within 0.5gr of each other and 50 rounds randomly pulled and headed to the range. I set up a target with 8 paper sticker dots. I fired five rounds of weight sorted ammo into each of the four dots in the top row. Then I fired the unsorted ammo at the second row.

Upon inspection, I found that I got on average 2.39MOA in the the weight-sorted ammo. On average, the weight-sorted groups were 7% smaller than the unsorted ammo groups. Comparing mean group sizes, there was only about a 5% difference. If not for an especially bad flyer in one target of the weight-sorted group, that number would have been 2.07 MOA or approximately 20% smaller than the unsorted group. The two smallest weight-sorted groups were almost half the size of the two smallest unsorted groups. And

While this difference, as a percentage, is not nearly as dramatic with 5.56mm as with my .22LR tests, both tests due confirm a significant improvement can be made by simply weighing your bulk box ammo. This is especially helpful due to our current pandemic induced ammo shortages, when Match Grade ammo is nearly impossible to find.

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Tom "Moondog" DelMundo is an award-winning copywriter and art director with over a decade of Madison Avenue experience.

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