22 Rimfire Ammunition

It all started with a Daisy Model 25 pump action air rifle, but the “neighborhood mafia” referred to them as “BB guns”. The Model 25 was accurate and propelled a round BB at about 350 feet per second, which was about 100 feet per second faster than other BB guns that were on the market at the time. It was pretty lethal for a BB gun and also shot to the sights. The Model 25 had a tedious-to-load tubular magazine that held approximately 50 BBs. However, my Model 25 buddies and I, developed a novel speed load technique by putting the BBs in our mouth, depressing the spring-loaded magazine lever and then spitting them into the magazine. Yep, I accidentally swallowed a few BBs; however, it was a small price to pay to be ready for the next target of opportunity. Although, I never put that BB gun on paper, I seldom missed a grasshopper. Back then, BBs were sold in red colored cylindrical tubes with the ends crimped like a shotgun shell. The empty BB cartons were never discarded. We would stuff them full of kitchen match heads, tape a stick to the side of the tube for stability and make rockets out of them. Other than starting a couple of lawn fires from BB pack rocket launches, no windows were shot out, no cars had BB dings in them, and the neighborhood pets were all safe.

Then came the 22 rimfire – a real gun. I was around 12 years old when I got a Remington Model 572 Field Master for Christmas. It was like the Daisy Model 25 in that it had a pump action and a tubular magazine. To be considered mature enough to own a rifle that shot real “bullets” was like a rite of passage for me. I loved that rifle and I shot it so much that the extractor finally failed. I also loved the 22 rimfire cartridge itself. Whether I was actually shooting the rifle or not, I always had a few 22 shells in my pocket. I even took loaded rounds in my pocket to school. There was never an incident and no one hyperventilated.

To this day, the 22 rimfire is – hands down – one of my favorite cartridges. By far, I own more rifles and handguns chambered in 22 rimfire than any other single chambering. Up until I began to compete in the 22 black powder silhouette game, my 22 rimfire shooting was more plinking than anything else. Testing ammunition for accuracy was never done; I was satisfied with run of the mill and budget priced ammo, as long as I could hit a can or rock at 25 or so yards. To be honest about it, I never even considered the fact that some brands of ammunition might be more accurate than others. Competition changed all that. Testing different brands of ammunition and honing my marksmanship skills with the 22 rimfire cartridge is something that I do all the time now.

Before I begin, I want to make it clear that this article is intended to be a general discussion on the ballistics and accuracy potential of 22 rimfire ammunition shot from my silhouette rifles. I do not intend to promote that one brand of ammunition is necessarily better or more or less accurate than other brands across different rifle platforms and barrel brands. Also, this endeavor is general in nature; brands were tested against brands. Comparing the accuracy of different lot numbers of the same ammunition was not conducted. Therefore, it is entirely possible that the specific lot number of a particular performance brand of ammunition may have produced better accuracy had I tested lots against lots of the same ammunition. Lot testing of rimfire ammunition is a very common and useful practice with serious 22 rimfire competitors. If 22 caliber rimfire ammunition becomes more available in the future, lot testing may be the topic of a follow-up article.

In my quest to achieve accuracy, I have tested different brands of rimfire ammunition ranging from cheap ammunition to high-end competition ammunition. In general, the cheap ammunition shot well enough to hit cans and small rocks at 50 yards but was inaccurate at distances beyond that. For the high-end competition ammo, most brands shot significantly better than the cheap ammunition; however, some still only provided around 1.5 to 2 MOA (minute of angle) groups. It was a disappointing reality to know that I could spend between 30 to 45 cents a round for high end ammunition and still only achieve 1.5 to 2 MOA.

After thinking about 22 competition and the targets we shoot at more, I decided that reverse engineering was in order. However, I needed to know what level of accuracy was needed to consistently hit targets and then try to find a load that could achieve that level of accuracy. So, I calculated how large a 1.0, 1.5, 2.0 and 2.5 MOA group would be on each animal at each distance. I also calculated the maximum MOA for each target. Those calculations can be found in the chart one below.

Based on this information, a 2.5 MOA group would keep all bullets on target except for rams. Assuming no shooter errors or bad wind calls were made, all rounds would theoretically be on target with a 2.0 MOA group. Comparing a 1 MOA group to a 2 MOA group, a shooter would have an extra ½-inch advantage on chickens, a 1-inch advantage on pigs, 1.7-inch advantage on turkeys, and a 2.2-inch advantage on rams by shooting a 1 MOA group. But, if a group is perfectly centered on the animal, the actual advantage is ¼-inch on top and ¼-inch on bottom for chickens, ½-inch on top and ½-inch on bottom for pigs, 7⁄8-inch on top and 7⁄8-inch on bottom for turkeys and 1.1-inch on top and 1.1-inch on bottom for rams. Just looking at the math, the differences between 1 MOA groups and 2 MOA groups seem small and insignificant, but if you look at a visual representation of what a 1 and 2 MOA group looks like on the animal itself, it gives you a different perspective.

So, how accurate must my rifle and ammunition be to potentially hit every target? The answer would be 2 MOA – that is, if my spotter can make 100 percent perfect wind calls and I never make a bad break. The obvious benefit of being able to select ammo that will shoot the smallest possible groups allows room on the target for poor wind calls or bad shots. Another way to think of this is, in essence, the smaller the group, the larger the target. For me, my goal is 1 MOA – at least for now.

After recent shooting sessions where different brands of rimfire ammunition were shot for group at 100 yards, it was obvious that some brands were clearly more accurate than others. I am sure that this does not come as a big surprise to anyone reading this article. Chronograph data (see the chart below) including maximum and minimum velocity, average velocity, extreme spread, and standard deviation provided some clues as to why such variability in accuracy was noted. However, the stats alone were not entirely definitive.

Although some ammunition had decent statistics, accuracy was disproportionately poor as compared to the statistics of some of the most accurate ammunition. Extremely low standard deviations are one statistical value that directly correlated with excellent accuracy potential. The most accurate ammunition (RWS-100 and Eley Benchrest Semi-Auto Precision) had extremely low standard deviations of 5.1 or below (see photo below).

Standard deviations that fell between 6.2 and 8.3 were the next best as far as accuracy was concerned with one exception, Center-X (see photo below). Center-X did not perform well in my rifle even though it had a very low standard deviation of 6.2. Another outlier was Midas+, with a standard deviation of 8.3; it shot extremely well and 100-yard groups were near equal to those achieved with RWS-100. Midas+ has been a consistent performer across the several rifle platforms that I own. All five Lapua brands had very respectable standard deviations that ranged from 6.2 to 8.3. Recently, I picked up a few boxes of Lapua X-Act. I have only shot this ammunition for group once, out of only one rifle, however, considering light but gusty wind conditions on the day of shooting, it also shot extremely well. The average velocities for X-Act, Midas+, Center-X, and Lapua Long Range were all nearly identical, ranging from a

low of 1,028.4 to 1,032.8 feet per second. Surprisingly, Lapua Super Long Range was only about 13 feet per second faster than Lapua Long Range.

Another bit of chronograph data that was interesting was the average velocity data. The two most accurate brands of ammunition I tested were RWS-100 and Eley Benchrest Semi-Auto Precision. Both had velocities above 1,050 feet per second. The Wolf Match Extra ammunition also chronographed with an average velocity of 1,098.8 feet per second, but it was marginally accurate at best. The reason for the inaccuracy of the Wolf ammunition is probably due to the wide variability in weight ranges per box of ammunition. This is discussed in the next section of this article. Midas+ was also very accurate in my rimfire rifles; however, the velocity was much lower than RWS-100 and Eley Benchrest Semi-Auto Precision ammunition.

I have read that premium rimfire ammunition has a narrow distribution of total cartridge weight ranges and this supposedly contributes to accuracy. So, I decided to “chase that rabbit” by weighing every cartridge in a 50-round box of many different brands of rimfire ammunition. This information can be found in the chart below. 

The total cartridge weight for Wolf Match Extra ranged from 50.2 to 52.5 grains, with no single weight category having greater than 12 percent of the cartridges in one box of ammunition fall in a particular weight range. The velocity extreme spread of the Wolf ammunition was 33.4 and was the highest extreme spread of all the ammunition chronographed. CCI Standard Velocity, SK Long Range Match and Federal Premium Gold Medal Target are also inaccurate in my rifles, but they did have a better weight range distribution than the Wolf ammunition. The Eley Benchrest Semi-Auto Precision also had a wide range distribution from 51.4 to 52.3 grains; however, 74 percent of the rounds in a box weighed between 51.7 to 51.8 grains. Over several shooting sessions and different rifles, I have shot some very good groups with the Eley Benchrest Semi-Auto Precision ammunition. At a price point of around 21 cents to 25 cents per round, this brand of Eley ammunition may be a reasonable alternative to some of the very expensive ammunition. Those shooters that may be interested in trying some of this ammo should be aware that there are two different brands of Eley Benchrest Semi-Auto ammunition; one is referred to as “Precision” and the other is labeled “Outlaw”. All testing for this article was with the Eley Benchrest Semi-Auto Precision ammunition.

It is obvious that the companies that manufacture the more expensive performance rimfire ammunition are paying attention to round-to-round weight variations. The Eley Match ammunition weighed between 51.3 and 51.5 grains, Lapua X-Act weighed between 51.8 and 51.9 grains, Lapua Midas+ weighed between 51.6 and 52.0 grains, Lapua Center-X and Lapua Long Range weighed between 51.8 and 52.0 grains, Lapua Super Long Range weighed between 51.6 and 51.9 grains, and RWS-100 weighed between 52.7 grains and 53.1 grains. Federal Ultra Match UM-1 has been out of production for quite some time. It was used by US Olympic shooting teams in the mid-1990s. From the little information that I can find about this ammunition, it was supposedly the most accurate 22 rimfire ammunition ever produced up until that time. UM-1 had a weight distribution of 51.5 to 51.7 grains with 96 percent of every round in a box of ammunition weighing within plus or minus 0.1 of a grain. The UM-1 ammunition, unlike currently produced rimfire ammunition, had a dimpled primer, which supposedly improved the uniformity of ignition of the priming compound.

The most consistently accurate ammunition for the three silhouette rifles I own is RWS-100, Eley Benchrest Semi-Auto Precision and Lapua Midas+. These three brands provided a high level of accuracy regardless of rifle platforms and barrel brands. RWS is made in Germany and imported. It is interesting to note that in my rifles, it produced the highest velocities and had the heaviest bullet weight of any ammunition that I have tested to date. Unfortunately, at this writing, RWS-100 is not in stock anywhere and distributors of this ammo do not have a clue as to when more will become available in the US. I was told by one distributor that RWS-100 was to be discontinued in the US market. Lapua Midas+ is made in the US, however, at this time, it also is difficult to find. At this writing, the Eley Benchrest Semi-Auto Precision ammunition is available from several sources.

I decided to call Lapua to gain insights as to their criteria or process used for making accurate rimfire ammunition. Even though they understandably have trade secrets they could not divulge, it was worth the call. If you haven’t visited the Lapua website, I suggest that you do so. There is much interesting information on their site, and Lapua’s commitment to rimfire competition is very evident and quite impressive. 

I talked to Ron Sponauer, the manager of the Lapua Capstone Precision Group in Mesa, Arizona. Ron has an extensive knowledge of the rimfire cartridge and how to properly test ammunition to achieve the best possible accuracy in your rifle. Ron is also an active rimfire competitor as well. 

The Capstone Precision Group is one of two Lapua facilities in the United States whose sole purpose is to test various brands and lots of Lapua rimfire ammunition. The other facility is the Lapua Rimfire Performance Center East and is located at the Cardinal Shooting Center in Marengo, Ohio. By appointment, a competitor can arrange to send his barreled action to one of the two rimfire test facilities for lot testing. This service is evidently quite popular; Ron told me that they currently have approximately 350 people waiting to send in their rifles for testing. This represents a wait of approximately seven months.

The testing involves shooting and chronographing various lots of three of Lapua’s premium brands of competition level rimfire ammunition. This includes Lapua X-Act, Lapua Midas +, and Lapua Center-X. The customer’s barreled action is mounted in a machine rest and testing is conducted in a controlled environment (test tunnel). The testing procedure takes about two to four hours to complete. At the end of testing, the customer is presented with test targets and performance data for each brand and lot of ammunition. At that time, arrangements can be made to purchase the particular brand and lot of ammunition that performed the best in the rifle. Several YouTube videos can be found online explaining the process in more detail.

The advantages of this program are obvious. First, it is currently almost impossible to find competition grade rimfire ammunition, much less finding different lots of the same ammunition. Even if it were possible to locate various lots of ammunition for testing, there is no guarantee that this ammunition would still be available to purchase after a competitor had conducted their own testing to determine the best performing lot. Second, testing ammunition at the Lapua test center eliminates variables such as shooter fatigue and wind conditions.

In my interview with Ron, I learned some interesting facts about Lapua rimfire ammunition. All their competition level ammunition (X-Act, Midas+, and Center-X) is produced using the same case material, priming compound, bullet weight/design, and powder charge. And, it is all produced on the same loading equipment. In the manufacturing process of these three brands, they do not know which brand they are making until the manufacturing process is complete. Their aim is for 100 percent of the ammunition produced for five case lots to be Lapua X-Act. After producing a run of five cases, Lapua then conducts tests to divide the five cases into one of their three premium brands. The parameters Lapua uses to separate ammunition into one of three different brands is a trade secret. Ron did tell me, however, that weighing of cartridges to determine weight ranges was not a criteria that is used to determine what ammunition qualified to be X-Act, Midas+ or Center-X. The information I obtained from weighing loaded cartridges bears this out. Based on my conversation with Ron, I came away with the idea that of these three brands, Lapua considers X-Act to be potentially the most accurate followed by Midas + and then Center-X. He also stated that this did not necessarily hold true across all of the rifle platforms he tests. Ron said it was not unusual for some barreled actions to shoot Center-X or Midas+ more accurately than X-Act. As stated previously, Lapua X-Act, Midas+, and Center-X are all made from the exact same components on the same machinery.

I also learned that Lapua Long Range and Super Long Range have the same bullet as X-Act, Midas+, and Center-X, but using different powder charges. Long Range and Super Long Range Lapua ammunition is made for a targeted velocity of 325 meters per second (1,066.3 ft/sec) and 335 meters per second (1,099.1 ft/sec) respectively. The chronograph data I observed from my rifle was 1,032.8 and 1,045.7 ft/sec for Lapua Long Range and Lapua Super Long Range respectively, however. Also, the same bullet lube and priming compound for all Lapua rimfire ammunition is the same, regardless of brand. SK rimfire ammunition, a subsidiary brand of Lapua, is produced at a different facility from X-Act, Midas+, Center-X, Long Range, and Super Long Range. 

At the time of shooting and testing, the only two brands of Eley rimfire ammunition that I could get my hands on were Eley Match and Eley Benchrest Semi-Auto Precision. The Eley Benchrest Semi-Auto Precision ammunition was very accurate, however, the Eley Match ammunition produced groups in the 1.5 MOA or greater range. Wolf Match Extra is for all practical purposes Eley ammunition because it is produced by Eley. It had a wide range of cartridge weights per box and was not accurate in any of my silhouette rifles. 

After all the testing, all the weighing and all the chronographing, I have circled back to the same conclusions that I had before I started in on all of this. The only way to find accuracy in your rimfire rifle is to do a lot of shooting with many different brands and lots of ammunition. What shoots well in your buddy’s rifle may or may not work in your rifle. Selecting ammunition because it is expensive and therefore it must be better, or because it is considered to be competition grade ammunition, may not necessarily yield a high level of accuracy in your particular rifle. Also, 1.5 MOA ammunition is not difficult to find, but 1 MOA ammunition is!