.22LR Ammo Dimensions
Posted: Sun Mar 05, 2023 9:27 pm
In a recent article in Guns & Ammo on the benefits of sorting .22LR ammunition Dave Emary came to a few conclusions. Dave is Hornady's Senior Ballistician. To make a long story short, he concluded that measuring rim thickness is the least worthwhile sorting method. Based on his experimenting the most significant factor is bullet runout (concentricity), and bullet head height being the next most important.
It should not be a surprise that runout is a contributing factor since sorting for runout is a common technique with high power precision shooters, but it’s not typically associated with rimfire ammo . He noted that he’d never heard of measuring .22 ammo head height which is the measurement from the base of the cartridge case to the top of the bullets driving band. It’s an interesting article. Since I have all the necessary gauges including a RCBS concentricity gauge I recently completed measuring 15 cartridges of several brands.
As expected, the more expensive ammo was better than the cheap stuff. But there were a couple of surprises. I expected the cheap Win Wildcat to be worse than the data suggested & was a little surprised to see how well the RWS R50 turned out. The SK Long Range was very consistent & it was no surprised that the Win. bulk plinking ammo was the worst of all the stuff I have.
Although Dave’s article I mentioned there’s little or no value in sorting by rim thickness, it’s easy to do. And based on other articles, weighing .22 ammo is not considered beneficial, but I was also curious. Determining head height was quick using Hornady's bullet comparator with .22 insert.
Measuring run-out (concentricity) was by far the most tedious measurement. Concentricity gauges are made for larger cartridges. I was able to use my RCBS Case Master Gauging Tool but it took some practice to develop the necessary technique due to the small size of the cartridge. Setting up the spread sheet, entering all the data required a good bit of time, but was necessary to utilize the statistical calculations. I was not about to do it using a hand calculator.
Overall this exercise was very time consuming. I did it out of curiosity & have no plans to continue sorting .22 ammo. And I do not plan to test fire the sorted ammo. BTW, for silhouette matches I shoot CCI Std. Target for the chickens & pigs, the Eley Match for the turkeys & rams.
Wayne
It should not be a surprise that runout is a contributing factor since sorting for runout is a common technique with high power precision shooters, but it’s not typically associated with rimfire ammo . He noted that he’d never heard of measuring .22 ammo head height which is the measurement from the base of the cartridge case to the top of the bullets driving band. It’s an interesting article. Since I have all the necessary gauges including a RCBS concentricity gauge I recently completed measuring 15 cartridges of several brands.
As expected, the more expensive ammo was better than the cheap stuff. But there were a couple of surprises. I expected the cheap Win Wildcat to be worse than the data suggested & was a little surprised to see how well the RWS R50 turned out. The SK Long Range was very consistent & it was no surprised that the Win. bulk plinking ammo was the worst of all the stuff I have.
Although Dave’s article I mentioned there’s little or no value in sorting by rim thickness, it’s easy to do. And based on other articles, weighing .22 ammo is not considered beneficial, but I was also curious. Determining head height was quick using Hornady's bullet comparator with .22 insert.
Measuring run-out (concentricity) was by far the most tedious measurement. Concentricity gauges are made for larger cartridges. I was able to use my RCBS Case Master Gauging Tool but it took some practice to develop the necessary technique due to the small size of the cartridge. Setting up the spread sheet, entering all the data required a good bit of time, but was necessary to utilize the statistical calculations. I was not about to do it using a hand calculator.
Overall this exercise was very time consuming. I did it out of curiosity & have no plans to continue sorting .22 ammo. And I do not plan to test fire the sorted ammo. BTW, for silhouette matches I shoot CCI Std. Target for the chickens & pigs, the Eley Match for the turkeys & rams.
Wayne