Match Ammo Lot Consistency over the Chronograph?

[grauhanen]

Ultimately there's only one way that matters -- which is on target, regardless of what a chronograph suggests. The question here is how consistent should shooters expect a lot of .22LR match ammo to be over the chronograph?

To be sure, no two boxes from the same lot of upper level ammo are identical. But how similar is the ammo within a lot of .22LR match ammo?

The question here deals with match ammo such as Lapua CX, M+ and Eley Match, Tenex, and RWS R50 and Special Match. (Entry level match ammos such as SK and more affordable Eley and RWS varieties may have considerable variation within a lot.)

 

[deadman]

I haven't chronographed any particularly high end ammunition, but out of curiosity I did check some lower end stuff.

As you noted a while back, mv can indicate a likely poi but isn't necessarily gospel.

I'm starting to think rimfire accuracy is akin to automotive electrical, it's just black magic.

Not having tested premium match ammo, I'm spitting in the dark but I'd hope for a max spread of 20 fps in velocity. But that's probably dreaming.

I've been meaning to chronograph my Eley Match but haven't at this point.

 

[Leuchtkafer]

Well, "match" ammo is factory made at the end of the day and for this reason it'll never be as consistent as could be possible for the cartridge if it were given the maximum care and attention possible. This simply will not happen in a production environment. Centerfire handloaders can get a 10fps MV spread, which has much less impact given the higher velocities they shoot at. What I've seen for R-50, Midas +, Tenex, is 30-40 fps ES. This isn't a large sampling of lots, just 1 or two of each brand that I bothered to run over a chronograph.

Humans can make 22 barrels and rifle platforms that are capable of performance exceeding what the ammunition is able to deliver. The next step up in rimfire precision will have to come from ammunition improvement. This means being able to handload, since the factories will never make the best ammo possible other than by a happy coincidence for a lot or two. So, whoever can figure out how to handload .22 LR will be the one to advance rimfire precision. The primer consistency plays a large role given that the powder charge is small, primer is less of a factor in large centerfire loads (it just has to get the powder burning). And since the powder charge of .22 is small, any variance of the charge has a greater impact percentage wise than it does in a centerfire load. In my experience handloading centerfire, the powder charge by volume is not consistent by weight, I have to set low and trickle up the weight of every charge to be consistent, and even still sometimes have to dump out a few grains from an over-charge. How can automated machinery possibly load .22 with equivalent consistency? They cannot.

 

[boxhitch]

They cannot. but what they can do is test and label according to consistency, which is the diff between Team Match and Tenex for example
I tested a few rounds of several ammos, the one maybe considered match ammo might be the Team with a spread from 1049 to 1075 = 26, while the S&B Cdn was 1074 to 1095 = 21, and Sport was 1083 to 1112 = 29, yet the Team was most accurate
Have some Match to chrony this week, though it seemed to produce flyers, maybe, more testing needed

 

[grauhanen]

Well, "match" ammo is factory made at the end of the day and for this reason it'll never be as consistent as could be possible for the cartridge if it were given the maximum care and attention possible. This simply will not happen in a production environment. Centerfire handloaders can get a 10fps MV spread, which has much less impact given the higher velocities they shoot at. What I've seen for R-50, Midas +, Tenex, is 30-40 fps ES. This isn't a large sampling of lots, just 1 or two of each brand that I bothered to run over a chronograph.

Humans can make 22 barrels and rifle platforms that are capable of performance exceeding what the ammunition is able to deliver. The next step up in rimfire precision will have to come from ammunition improvement. This means being able to handload, since the factories will never make the best ammo possible other than by a happy coincidence for a lot or two. So, whoever can figure out how to handload .22 LR will be the one to advance rimfire precision. The primer consistency plays a large role given that the powder charge is small, primer is less of a factor in large centerfire loads (it just has to get the powder burning). And since the powder charge of .22 is small, any variance of the charge has a greater impact percentage wise than it does in a centerfire load. In my experience handloading centerfire, the powder charge by volume is not consistent by weight, I have to set low and trickle up the weight of every charge to be consistent, and even still sometimes have to dump out a few grains from an over-charge. How can automated machinery possibly load .22 with equivalent consistency? They cannot.

This is a good observation, one that sounds remarkably like those made in the past on the topic here on this forum by the now-banned Rabid (RabidM4U5).

Are you by chance the same Rabid, now posting under a new identity? Coincidentally, you became a CGN member not long after he was banned. Like you, he also had an older Anschutz that he couldn't get to shoot. Like you, he recommended a certain import service for barrels. Like you, he often posted in the wee hours. And like you, he was a CZ fan. The "you're out of your league" comment you made recently certainly sounded like something the frequently and unnecessarily combative Rabid would say. Of course all this may be coincidence.

In any case, the above comment is as good now as it was in the past.

 

[grauhanen]

Until this year, I had believed that a .22LR match ammo lot was reasonably consistent. In previous years when I tested different lots of Lapua ammo over the chronograph I believed one or two boxes would be enough to reveal the extreme spread (ES) and standard deviation (SD) to expect from other boxes from the same lot. After all, .22LR match ammo like Center X and Midas + should be reasonably consistent in a reliable sort of way.

When I compared different results for a lot of Lapua's top tier ammo, X-Act, I began to wonder if my belief in the consistency of ammo was misplaced.

In 2021, a box tested had an ES of 54 fps with an SD of 10. In 2022, one box had ES and SD figures of 54 and 11 and a second had a much better ES of 33 and SD of 8 fps. Why the difference? Something was weird here. When I tested a fourth box this year, the result was an ES of 70 fps and an SD of 13 fps.

So this year I thought I ought to test other match ammos to see if the X-Act results were an anomaly and how much intra-lot variation there was.

See the next post for some of the data.

 

[grauhanen]

Below are the results of the three lots of Lapua Center X ammo I tested this year. This ammo was manufactured in 2022. For anyone wondering about the rifles used, one is a Anschutz BR 1913, which has a 69cm (27.2") barrel. I also tested with an Anschutz BR 1907, which has a 66cm (26") barrel. And I also used what was originally a 50 year old 1411 with a 69cm barrel.

I think the ES and SD figures may be the most important in comparing the results. Extreme spread is easy to understand. It shows the slowest and fastest rounds in a sample. This can have implications for vertical dispersion. Standard deviation (SD) is not quite as straightforward. As the Guns and Ammo editors explained a few years ago,
Put in terms those of us that are math challenged can understand, SD is a measure of how spread out numbers, data or whatever we are sampling is from the average. The smaller the SD, the less variation there is of the data from the average. The bigger the SD, is the bigger the variation there is of the data points from the average.
See https://www.gunsandammo.com/editori...-extreme-spread-and-standard-deviation/247510

Put another way, the smaller the SD number, the closer the rounds in the sample are to each other in terms of MV.

It should be noted that warmer temperatures tend to produce MVs that are a little faster. It should also be noted that Lapua's factory rated lot MV averages are derived from the first two digits in the lot number. Put a "3" in front of those numbers and you have the Lapua factory rated average MV of the lot. For example, a lot begins with the two digits "25" would be 325 meters per second or 1066 fps. A lot number beginning with 27 would be 327 m/s or 1073 fps. A lot number starting with 28 would be 328 m/s or 1076 fps. (Remember these are factory averages in factory test barrels.)

Of course actual MV varies by the particular barrel, especially by its bore characteristics, not necessarily by its length.

 

[grauhanen]

Data for five different lots of 2022 Lapua Midas + is available if there's interest.

 

[Williwaw]

Thanks Glenn, still digesting the above but would definitely appreciate more. Thanks for posting the info.

 

[_Shorty]

Rimfire accuracy is an incredibly deep rabbit hole. Chronograph measurements are just one thing to consider. I wouldn't bother wasting much time worrying about ES. It doesn't let you predict anything. If you want to help make predictions about what any given ammo might be capable of, you should be looking at SD. It is a value that actually lets you make predictions. ES doesn't really let you do that, as it is practically a single sample of a worst-case scenario that may or may not ever happen again. The SD value lets you know what you can expect shot after shot after shot.

What kind of shooting are you doing? Trying to set new benchrest records? Plinking pop cans? Headshotting grouse? Different expectations from one extreme to the other. And vastly different roads to arrive at the intended results.

One of the biggest things to consider when chasing rimfire accuracy is lot testing. You can have ten different lots of the same brand/line of ammo and shoot a box of each in the same gun and see wildly differing results. Do the same thing with a different gun and you might see different lots performing better in it than you saw with the first gun. A big thing with lot testing is simply matching up random differences in one lot with the chamber in that gun, which you do simply by trying different lots until you find one that shoots better than the next. And then buy as much of that lot as you can afford. I've got a silhouette gun that can shoot very well at all four distances for that game, which is at 40 m, 60 m, 77 m, and 100 m. But it doesn't shoot the same at all four distances. Nor will any gun. I've seen it shoot pretty small groups at 77 m, where I usually do lot testing, with some lots of ammo and then move on to the next lot and it starts dropping 5 or more shots out of a box of 50 down by more than 15 cm from the main group. Try that "bad" lot in another silhouette gun and it shoots decent groups with no dropped shots. Why? Some random difference in it that just doesn't get along with the first gun, but has no consequence in the second gun. And so, the second gun shoots it just fine, when the first gun makes it look like the worst ammo ever. You gotta try it in your gun before you know how it will shoot.

Chronograph numbers matter, but only to a degree. If you have some lot testing results and are having trouble deciding whether lot 123 is better than lot 456 based on what you're seeing on the paper, but one of the lots showed a slightly better SD, in that case you let the SD decide for you. You can have a better SD with worse groups, though. So you can't just decide based on SD alone. If it doesn't fit the chamber well it probably won't group very well, but could still show a decent SD.

Chronographs have their uses, but they're not the ultimate word. They just have a say in the conversation. Sometimes they might have something very important to say, and sometimes they might not. I just finished testing five different lots of Eley Tenex for my benchrest gun, and I'm waiting on the case of the winner to show up. Once it does I will be relying very heavily on the chronograph to help set up the tuner. In that endeavour it can be invaluable to help determine what is going on between the barrel and the tuner if you know what you're doing. But that's an entirely different scenario than getting the silhouette gun(s) into happy places, and consists of an entirely different happy place all of its own. The type of shooting you're doing, the kind of equipment you're using, will lay out the arena you're playing in. And whichever game that happens to be should indicate how big a part of the picture a chronograph might play. I had a small amount of a lot number of Eley Team that would shoot with SDs like 3.4 fps out of my bench gun, and I was shooting scores like 2350/2500 in our BR50 matches with it. All five of the lots of Eley Tenex that I just tested gave SD figures around double that, but I didn't see any bad outliers with any of those lots like I would occasionally with the Team. This is kind of to be expected, given that Team is about half the cost. The SDs I'm seeing with the Tenex being in the 6-8 fps range might make it seem like it's only going to shoot noticeably worse than the Team was if that's all you look at, but that's only part of the puzzle. There are other aspects of the ammunition that are more consistent, which help lead to more consistent results on paper, despite an SD figure that looks worse.

I've had a LabRadar for a few years now and have been keeping track of a fair amount of the data it spits out. It can be used in quite a few interesting ways. But ultimately it is only of so much use, and you need to figure out what those uses are, and whether or not those uses matter much to the kind(s) of shooting you're doing.

 

[grauhanen]

Shorty, that's a good post.

Readers should note that the chronograph data is not about how the ammo actually performs. It's an analytical tool for attempting to explain why the results are what they are, even -- or especially -- when they do not match chronograph predictions.

Rimfire accuracy is an incredibly deep rabbit hole. Chronograph measurements are just one thing to consider. I wouldn't bother wasting much time worrying about ES. It doesn't let you predict anything. If you want to help make predictions about what any given ammo might be capable of, you should be looking at SD. It is a value that actually lets you make predictions. ES doesn't really let you do that, as it is practically a single sample of a worst-case scenario that may or may not ever happen again. The SD value lets you know what you can expect shot after shot after shot.

While ES is indeed only a snapshot of the extremes of the sample, when analyzing chronograph results both ES and SD should be considered together. ES offers a theoretical vertical dispersion for a sample of ammo such as a box, which is increasingly relevant as distance to target grows. In practice, of course, the results can be something else. At the same time, the similar SD figures don't mean similar results downrange.

Even with shooter and wind removed as factors, results on target are always the product of all ammo characteristics. Muzzle velocity is only a part of the picture.

One of the biggest things to consider when chasing rimfire accuracy is lot testing. You can have ten different lots of the same brand/line of ammo and shoot a box of each in the same gun and see wildly differing results. Do the same thing with a different gun and you might see different lots performing better in it than you saw with the first gun. A big thing with lot testing is simply matching up random differences in one lot with the chamber in that gun, which you do simply by trying different lots until you find one that shoots better than the next.

This is a key issue in rimfire performance. What specific characteristics of a bore/chamber do you believe causes a particular rifle to perform better or worse with different lots of ammo? Or is it the ammo itself -- that some lots are simply better than others?

Chronographs have their uses, but they're not the ultimate word. ...

There are other aspects of the ammunition that are more consistent, which help lead to more consistent results on paper, despite an SD figure that looks worse.

Indeed, chronographs themselves don't shoot and results downrange would be the same if they weren't used.

It's exactly those other aspects of ammunition that interest me and presumably other shooters as well. What are those other aspects that must be more consistent to help deliver more consistent results downrange -- regardless of what numbers chronographs produce?

 

[grauhanen]

Check out the box-to-box consistency of this lot of RWS Special Match, a Premium Line variety of RWS .22LR match ammo which includes R50 and R100.

RWS also has a the lower tier Professional Line, such as RWS Rifle Match and RWS Rifle Match S, and even lower Sport Line ammos, such as RWS Target Rifle and RWS Club.

RWS Special Match might be comparable to Lapua Center X, in terms of position in the ammo hierarchy of each manufacturer, not to mention pricing. A comparable offering from Eley might be Eley Team ammo.



With ES ranges from the low 20s to the mid 40s, and SD figures from as low as 5 up to 10, there's seems to be some inconsistency within the same lot from one box to the next.

The figures from the three lots of Lapua Center X shown above are similar. They have ES ranges from the low 20s to the mid 40s as well. The SD figures range from a low of 5 to 10 fps.

_________________________________

Are these ranges in ES and SD numbers typical of these grades of .22LR match ammo? Perhaps the four lots of these mid-level match ammos are among the most inconsistent lots produced by Lapua and RWS. Perhaps they are typical. To be sure, I don't know if they are.

Perhaps the "better" grades of match ammo such as Lapua Midas + are more consistent from one box to another within the same lot. Shooters buying this ammo might hope that Midas is much more consistent. After all it costs more. Midas goes for about $250 per brick, while CX is about $200, which itself is not inexpensive.

Is the Midas + we get in Canada more consistent?

 

[OkayShooter]

Honestly I think rimfire ammo no matter what, is soo mass produced that you will always get inconsistency. Never will have 100%.

Unless you are using a radar chrony, your at the mercy of the clouds, so will always be a slightly change in the lighting, that can reflect the velocity.

 

[boxhitch]

......
When I compared different results for a lot of Lapua's top tier ammo, X-Act, I began to wonder if my belief in the consistency of ammo was misplaced.

In 2021, a box tested had an ES of 54 fps with an SD of 10. In 2022, one box had ES and SD figures of 54 and 11 and a second had a much better ES of 33 and SD of 8 fps. Why the difference? Something was weird here. When I tested a fourth box this year, the result was an ES of 70 fps and an SD of 13 fps.

Compared to your charts for Center X , one could assume the X-Act is not so exact as expected

 

[Mystic Precision]

Honestly I think rimfire ammo no matter what, is soo mass produced that you will always get inconsistency. Never will have 100%.

Unless you are using a radar chrony, your at the mercy of the clouds, so will always be a slightly change in the lighting, that can reflect the velocity.

Just remember what the end use goals for any top level rimfire match ammo is. As long as enough of them go through the same hole from their desired rigs at 1 distance, that is all that matters... and by the way, that stuff, we don't get to see

We worry about velocities because we are trying to use ammo in a way the manfs never intended. And often, these numbers don't reflect what is happening on paper at distance anyways.

Ask a SR benchrest shooter what their numbers are like.... might surprise you how much they vary... but they only have to converge at one distance

Jerry

 

[OkayShooter]

Just remember what the end use goals for any top level rimfire match ammo is. As long as enough of them go through the same hole from their desired rigs at 1 distance, that is all that matters... and by the way, that stuff, we don't get to see

We worry about velocities because we are trying to use ammo in a way the manfs never intended. And often, these numbers don't reflect what is happening on paper at distance anyways.

Ask a SR benchrest shooter what their numbers are like.... might surprise you how much they vary... but they only have to converge at one distance

Jerry

Not saying velocity doesn't matter. Its one of those things if you want 100% across the board, you'll pull you hair our trying. Best you can is, close as the same velocity, so like I said, will have some variance in the readings. As we are doing the testing outside, not inside, not in a rail gun, so there is some human factor in play, fluctuating lighting etc.

As for lots there also the factor of the lead, and the variance in the lead and where they got it. Can seperate a bit while being melted.

 

[_Shorty]

While ES is indeed only a snapshot of the extremes of the sample, when analyzing chronograph results both ES and SD should be considered together. ES offers a theoretical vertical dispersion for a sample of ammo such as a box, which is increasingly relevant as distance to target grows. In practice, of course, the results can be something else. At the same time, the similar SD figures don't mean similar results downrange.

39% of shots will land within 1 SD, and 86% of shots will land within 2 SD, and 99% of shots will land within 3 SD. You can gain none of that information from ES. It is not predictive like SD is. It is only two samples and they could be practically any random value within the whole. It seems most people don't understand what ES actually means, with regard to the statistics side of things and what statistics can tell you. You're saying what most people do about it, that it helps you predict the worst you can expect, but it doesn't. It is evidence of the worst you just witnessed up until that moment, but it doesn't tell you anything about future possibilities. It is not predictive. It is an after-the-fact witness.

What specific characteristics of a bore/chamber do you believe causes a particular rifle to perform better or worse with different lots of ammo? Or is it the ammo itself -- that some lots are simply better than others?

Well, it's a dance, isn't it? The chamber and the ammo need to get along nicely together. Part of it is how the ammo fits in the chamber, and part of it is naturally due to some of the other characteristics of the ammo. Match chambers exhibit more consistent behaviour. Match chambers are all tighter than the average chamber. They'll hold the round in a more contained space, allowing it to change less during firing, which should produce more consistent burns from shot to shot. Which chamber dimensions are more important? Are they all important? How tightly do you hold the front of the case? How tightly do you hold the rear of the case? How steep of an angle do you choose for the leade? How long or short do you make it overall? That is, how much of the bullet do you want to engrave into the rifling? All these things make a difference, both in function and in performance. Can't have an Eley Ultimate EPS chamber in a 10/22 if you want it to successfully cycle round after round through its semi-auto action. It'll be too tight and will constantly cause feeding and/or extraction issues. The Bentz chamber was a compromise to help it shoot better while still functioning fairly well most of the time, but it was too loose to shoot extremely well. And it is still considering a match chamber, and has tighter dimensions than the garden variety sporter chamber.

You've got to have consistent everything to get consistent results. Bullets need to all be the same size and shape. That's unlikely, given what they are and how they're handled during manufacturing and up until it hits your doorstep, but more expensive match ammo tends to have more consistent bullets. Changes in shape result in changes in flight. Powder charges need to release the same amount of energy at the same rate. Primers, too, as they contribute a lot to the velocity. And they need to ignite the powder the same way every time so it can burn the same way every time. And your firing pin needs to impart the same amount of force every time. The list goes on and on.

 

[_Shorty]

Here are some numbers from my recent testing of five lots of Eley Tenex. (Sorry about the JPGs, but for some reason the forum doesn't like my PNGs.)



Eley Tenex 1022-02294 target - 100 shots - 50 yards



Eley Tenex 1022-02296 target - 100 shots - 50 yards


Eley Tenex 1022-03228 target - 100 shots - 50 yards


Eley Tenex 1022-04336 target - 100 shots - 50 yards


Eley Tenex 1022-06176 target - 100 shots - 50 yards


I think I can also look up data on that lot of Eley Team I had that shot very well, and a lot or two of Center-X that did not, and a lot of Midas+ that did not, and maybe a few older lots of Eley Match. Might also be able to figure out which series were from RWS Special Match, RWS Semi Auto, maybe some SK Rifle Match, and some others. Just a matter of time. Got a bit of data stored here on the computer, but would have to consult notebooks to figure out which is which in most cases. The Eley Team, Center-X, and Midas+ are probably the easiest to figure out as they're pretty recent.

 

[_Shorty]

Compared to your charts for Center X , one could assume the X-Act is not so exact as expected

Just another example of how you have to find what works with any particular gun. You can take 10 guns and shoot the same lot through all of them and looking at isolated results come up with 10 different answers as to whether or not the ammo was any good. Every chamber is different. Every barrel is different. Every set of equipment is different. I can make my gun shoot incredibly differently with just a twist of the side clamp tension knob on my one-piece rest's front top. Can make 2350-score ammo shoot 1700s very easily.

 

[grauhanen]

39% of shots will land within 1 SD, and 86% of shots will land within 2 SD, and 99% of shots will land within 3 SD. You can gain none of that information from ES. It is not predictive like SD is. It is only two samples and they could be practically any random value within the whole. It seems most people don't understand what ES actually means, with regard to the statistics side of things and what statistics can tell you. You're saying what most people do about it, that it helps you predict the worst you can expect, but it doesn't. It is evidence of the worst you just witnessed up until that moment, but it doesn't tell you anything about future possibilities. It is not predictive. It is an after-the-fact witness.

Let's not flog how important or unimportant ES figures are. No one suggested that ES was the most important. Of all the chronograph information shown, readers may consider it and SD as more important than average MV or the minimum - maximum velocities. Anyone is welcome to ignore ES data and restrict themselves to SD. Neither ES nor SD will guarantee what the results on target will look like.

Well, it's a dance, isn't it? The chamber and the ammo need to get along nicely together. Part of it is how the ammo fits in the chamber, and part of it is naturally due to some of the other characteristics of the ammo. Match chambers exhibit more consistent behaviour. Match chambers are all tighter than the average chamber. They'll hold the round in a more contained space, allowing it to change less during firing, which should produce more consistent burns from shot to shot. Which chamber dimensions are more important? Are they all important? How tightly do you hold the front of the case? How tightly do you hold the rear of the case? How steep of an angle do you choose for the leade? How long or short do you make it overall? That is, how much of the bullet do you want to engrave into the rifling? All these things make a difference, both in function and in performance.

You've got to have consistent everything to get consistent results. Bullets need to all be the same size and shape. That's unlikely, given what they are and how they're handled during manufacturing and up until it hits your doorstep, but more expensive match ammo tends to have more consistent bullets. Changes in shape result in changes in flight. Powder charges need to release the same amount of energy at the same rate. Primers, too, as they contribute a lot to the velocity. And they need to ignite the powder the same way every time so it can burn the same way every time. And your firing pin needs to impart the same amount of force every time. The list goes on and on.

It is indeed a dance. It's worth noting that over the years BR shooters have used different chambers (all "match" chambers, of course) and many different ones have achieved success. There is as yet no chamber dimension that is head and shoulders above all others.

Nevertheless, despite the success chambers with different dimensions, if we allowed that certain chamber dimensions are in fact key to performance, it is in the end pointless without round-to-round consistency in the ammo itself. With top tier ammo and good rifles many of the factors you've identified are usually not major issues. From your list is there any single factor or ammo characteristic that you think is the most critical component or factor responsible for having round with very similar and consistent trajectories?