I've often wondered about what kind of accuracy results are possible in as near perfect conditions -- no wind and moderate temperatures -- as rimfire shooters dare hope for. The best way to accumulate results is by shooting in an ammo testing facility test tunnel. There's no wind and it's room temperature.
The major ammo makers have such facilities, including Eley's in Okotoks, Alberta. There shooters' rifles can be tested from a vise or fixture in a testing tunnel to evaluate ammunition and rifle performance. Lapua has two in the U.S., one in Arizona and one in Ohio. There, electronic sensors record data at 50 and 100 meters so that the exact location of where a round would strike a target at these distances is recorded. As a result it's easy to record accurate results and group sizes at the two distances.
The testing is done with the barreled action in a special fixture or the rifle itself in a special vise. The testing facility staff can test a number of different lots of ammo with the barreled action/rifle fixed solidly, giving consistent results. Below are examples from one of the Lapua facilities, very likely the one in Ohio.
To see what kind of results rifles are getting, the following data was collected for ten different rifles. All the ammo was from different lots of Lapua Center X. The rifles are identified at the top. The sizes are for ten ten-round-groups, measured outside-to-outside in millimeters. DRMS is a statistic that refers to distance root mean square which can be defined as "the radius of a circle that will be expected to contain the center points of ~65% of all future shots fired based on those already fired."
Please note that Lot 1 may not have been the same between each rifles because the rifles were tested on different days and the order of lots used may be different from day to day and rifle to rifle.
What will become apparent, is how much variation there is between lots. In most simplest terms it means is that not all lots of a particular ammo, in this case Center X, shoot the same. It would have been interesting to see how the same lots fared between the different rifles, but that data is not available.
I can't seem to get the complete table image to load here in a size where all the information is easily visible. What I've done is to post the complete chart first. I divided it in the middle and posted each half below the full chart, first the left side and then the right.
This table is from h t t p s://www.snipershide.com/precision-rifle/22lr-lot-testing-at-lapuas-indoor-100m-test-facility-what-should-you-expect-in-gains/
There will be variation in group sizes within any lot being tested. As a result no one would select a lot on the basis of the results of a single ten shot group. But clearly these results begin to give an indication of how much variation there is between lots of the same ammo with the same rifle. Whenever testing any ammo it's always best to test as much of the ammo as possible in order to see how much variety in performance there is in a lot. One good group doesn't guarantee a lot of good groups, and one bad group doesn't mean that it's truly representative of how the lot shoots.
Regarding the performance of the ten different rifles, the mean (average) ten-shot-group sizes are an indication of a particular rifle's performance. The three rifles with the best mean at 50 meters were the same rifles with the same mean at 100. The poorest means at 50 meters were from those rifles with factory barrels.
Surprisingly, the differences at 100 meters seemed less pronounced than at 50. Only the custom Stiller and Turbo had 100 meter groups less than 29mm OD. All the others were from just over 31mm to just under 34.
The major ammo makers have such facilities, including Eley's in Okotoks, Alberta. There shooters' rifles can be tested from a vise or fixture in a testing tunnel to evaluate ammunition and rifle performance. Lapua has two in the U.S., one in Arizona and one in Ohio. There, electronic sensors record data at 50 and 100 meters so that the exact location of where a round would strike a target at these distances is recorded. As a result it's easy to record accurate results and group sizes at the two distances.
The testing is done with the barreled action in a special fixture or the rifle itself in a special vise. The testing facility staff can test a number of different lots of ammo with the barreled action/rifle fixed solidly, giving consistent results. Below are examples from one of the Lapua facilities, very likely the one in Ohio.
To see what kind of results rifles are getting, the following data was collected for ten different rifles. All the ammo was from different lots of Lapua Center X. The rifles are identified at the top. The sizes are for ten ten-round-groups, measured outside-to-outside in millimeters. DRMS is a statistic that refers to distance root mean square which can be defined as "the radius of a circle that will be expected to contain the center points of ~65% of all future shots fired based on those already fired."
Please note that Lot 1 may not have been the same between each rifles because the rifles were tested on different days and the order of lots used may be different from day to day and rifle to rifle.
What will become apparent, is how much variation there is between lots. In most simplest terms it means is that not all lots of a particular ammo, in this case Center X, shoot the same. It would have been interesting to see how the same lots fared between the different rifles, but that data is not available.
I can't seem to get the complete table image to load here in a size where all the information is easily visible. What I've done is to post the complete chart first. I divided it in the middle and posted each half below the full chart, first the left side and then the right.
This table is from h t t p s://www.snipershide.com/precision-rifle/22lr-lot-testing-at-lapuas-indoor-100m-test-facility-what-should-you-expect-in-gains/
There will be variation in group sizes within any lot being tested. As a result no one would select a lot on the basis of the results of a single ten shot group. But clearly these results begin to give an indication of how much variation there is between lots of the same ammo with the same rifle. Whenever testing any ammo it's always best to test as much of the ammo as possible in order to see how much variety in performance there is in a lot. One good group doesn't guarantee a lot of good groups, and one bad group doesn't mean that it's truly representative of how the lot shoots.
Regarding the performance of the ten different rifles, the mean (average) ten-shot-group sizes are an indication of a particular rifle's performance. The three rifles with the best mean at 50 meters were the same rifles with the same mean at 100. The poorest means at 50 meters were from those rifles with factory barrels.
Surprisingly, the differences at 100 meters seemed less pronounced than at 50. Only the custom Stiller and Turbo had 100 meter groups less than 29mm OD. All the others were from just over 31mm to just under 34.
