Most consistent velocity 22 LR Ammo?

Maple57 said:
As far as velocity consistency went there were a few stand outs…
Eley Tenex 17 FPS ES over 10 shots,
Eley Club 23 FPS ES over 10 shots,
RWS Pistol Match 24 FPS ES over 10 shots
Browning BPR 61 FPS ES over 10 shots
CCI Velociter 120 FPS ES over 10 shots

With a 100 yard zero, a speed variation of 60 FPS equals 1.58 vertical inches at 200 yards and 4.62 vertical inches at 300 yards…. And a few of the ammo tested is less than half of this.
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As an observation, to get meaningful ES results it is necessary to have a larger sample size than 10 shots. A string of 30 will produce more reliable results.

A 60 fps ES will result in considerably more than 1.58" of vertical spread at 200 yards. That is a relatively high ES for long range .22LR shooting. It will be closer to 6 inches.
 
grauhanen said:
As an observation, to get meaningful ES results it is necessary to have a larger sample size than 10 shots. A string of 30 will produce more reliable results.

A 60 fps ES will result in considerably more than 1.58" of vertical spread at 200 yards. That is a relatively high ES for long range .22LR shooting. It will be closer to 6 inches.
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A string of 500 would be even more correct then wouldn't it. How can you pull on number out of the air as arbitrary as 30? It goes without saying that the larger the sample size, the more statistically relevant the value is, but I am not conducting a thesis on ballistics here, just framing generalities.

Actually no... 1.58 is correct...I ran the numbers in the ballistics software and that is the mechanical result of a 60 FPS velocity change.

The reality is there are other factors at work besides the velocity changes. If you want to include them as well, then it depends on weather conditions which change from day to day. On a good day, like just as a fog clears is the best possible conditions I have ever shot in and 1.58 would be fair during those conditions.

That is not to say the group would be 1.58 inches tall. More correctly the center of the group of fast ones could be as high as 1.58 inches above the center of the group of slow ones.
 
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For the Browning BPR ammo with High 1465 and Low 1405 MVs, I get about 2.2" of vertical at 200 yards in a ballistic calculator. Ammo less than 1100 fps MV will be more like 6-7 inches of vertical for that 60 fps ES. Figure roughly an inch per 10 fps velocity variation for SV ammo.

Sure, a large sample size will give more accurate ES numbers, but I typically see that in a box of 50 rounds, it is only a couple of outliers that bump up the ES. The bell-curve generated from the Standard Deviation value would be a better descriptor of where the majority of the rounds will fall vertically. It would of course be preferable to couple low SD with low ES so that those few outliers don't stray too far off the mark.
 
RabidM4U5 said:
For the Browning BPR ammo with High 1465 and Low 1405 MVs, I get about 2.2" of vertical at 200 yards in a ballistic calculator. Ammo less than 1100 fps MV will be more like 6-7 inches of vertical for that 60 fps ES. Figure roughly an inch per 10 fps velocity variation for SV ammo.

Sure, a large sample size will give more accurate ES numbers, but I typically see that in a box of 50 rounds, it is only a couple of outliers that bump up the ES. The bell-curve generated from the Standard Deviation value would be a better descriptor of where the majority of the rounds will fall vertically. It would of course be preferable to couple low SD with low ES so that those few outliers don't stray too far off the mark.
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Curious... "I get about 2.2" of vertical at 200 yards in a ballistic calculator".??? What BC and zero distance did you use? I used 100 Yard zero and 0.11 G1 BC

In my rifle I had a low of 1392 and a high of 1453 with BPRs... my buddy got over 1500 FPS with his Sako Quad.

At 200 to 300 yards the 3 of us shooting yesterday preferred the Browning BPR ammo in the switchy conditions of yesterday... probably for the reason you pointed out.

I agree SD is better, but ES is quick to determine without calculations... so certainly my laziness is to blame... For good ones... good was good... for the bad ones... it was not just one single round that made the data look skewed... the bad ones were clearly more random in general.

I think in a PRS match we'd need to make the call depending on the weather of the day before deciding to go with sub sonic or super sonic ammo. In mild conditions I would clearly favor low ES low velocity ammo, but if the wind gets dicey, I think the high velocity stuff will out perform.

There are other less tangible advantages of the high velocity ammo... It shoots about 5 MOA flatter at 100 yards, and once you zero the scope for that, you get an extra 5 MOA of scope travel for the long shots. Couple that with less need for travel at 300, since the 1435 FPS stuff is about 10 minutes flatter than the 1075 FPS ammo at 300 yards.

I didn't have the 41 MOA needed for 300 yards with 1.75 FPS and I had to dial up 30 MOA and hold high by another 10... that can get confusing in a match and that's how mistakes get made.

With the 1435 FPS ammo I could dial all the way to 300 yards with my scope, but at the travel limit there is no windage available.

The scope I'm running on a 20 MOA rail is the 6-24 Vortex Diamondback Tactical and that model only has 65 MOA travel... In retrospect the 4-16 would have been a better choice because it has 85 MOA travel... and that extra 10 MOA per side would just about make it to 300 yards even with 1075 FPS ammo. At the very least there would be windage travel available for 300 yards with 1435 FPS ammo.
 
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Mystic Precision said:
This is how I decide on my ammo.

I will test each type at 100yds/m and do maybe 3X5rds of each type fouling/swabbing the bore between types.

With the best ammo, I will measure base to ogive and sort per thou... I will then retest at 100 and 200yds to find the best length range for that ammo. Usually the bulk of the ammo will fall within a 3 to 4 thou range and that shoots best... I use the outliers for foulers and practise.

Figure out your dope to whatever your max distance is and test on target way out there. If it tracks and repeats... go compete.

Have fun...

Jerry
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How are you measuring from the base to the ogive?
 
Maple57 said:
A string of 500 would be even more correct then wouldn't it. How can you pull on number out of the air as arbitrary as 30? It goes without saying that the larger the sample size, the more statistically relevant the value is, but I am not conducting a thesis on ballistics here, just framing generalities.
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I wasn't trying to be argumentative. It is worthwhile to separate arbitrary contentiousness from hopefully helpful suggestion. My point was that a sample size of 10 is too low to be statistically reliable or useful. A sample size three times as large is more useful. And indeed a sample size of 500 even more so. It is important to do what is practical in an effort to produce results that are still useful. Shooting 500 rounds over a chronograph to determine ES (and SD) would give very good results but it is much more practical to shoot 30 rounds as it is not onerous nor excessively costly. In short, 30 shots is doable, 500 is not.
 
Here's the thing about supersonic .22 rimfire ammo, it looses velocity at a faster rate than subsonic ammo, and the lighter the bullet, the shorter the range when it actually enters the transonic velocity. The best accuracy is realized when the bullet doesn't break the sound barrier. I'd take a hard look at Lapua Biathalon.
 
Maple57 said:
Curious... "I get about 2.2" of vertical at 200 yards in a ballistic calculator".??? What BC and zero distance did you use? I used 100 Yard zero and 0.11 G1 BC
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30 yard zero. Something that can skew your results is using that 100 yard zero. The ballistic calculator will change the launch angle of the projectile to still hit your zero when you change the velocity. In the real world, you don't know when velocity will be variable, so your launch angle remains static/fixed. Using a 30 yard zero still isn't perfect, but the change in launch angle for the shorter distance is much less and the table results are much more representative of the drop you will actually observe at long range.
 
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I was thinking about what is more important... Standard Deviation or Extreme Spread...

I'm thinking extreme spread is much more important than standard deviation.

Here's why...

Supose you are comparing two different rounds and both have similar Standard Deviation, but one of them has a wider Extreme Spread.

For the round with a wider extreme spread to have a low SD it would have mostly rounds of similar velocity with the occasional shot that is well outside that norm.

When shooting in competition you are calling off feedback from shots fired.

So you are doing well and trying to center your group as you shoot, then out of nowhere your round hits low....

What do you do?

You can either dismiss the shot as a velocity change and keep aiming where you were, or you can adjust for the shot and adjust your point of aim to compensate.

If the low round was due to a velocity shift you dont know it and therefore adjust your point of impact to compensate and your next shot, if it is back to the base velocity range your next shot will be high.

At this point the one slow shot cost you 2 bad shots in the group... not just one.

If you select a round with a low extreme spread, the scenario described above is less likely to occur.

You are less likely to get shots with an out of the norm velocity and you will be adjusting your point of aim and centering the group based on a variation that is closer to the statistical average.
 
grauhanen said:
If someone measured rims and culled those that aren't supposed to shoot in a rifle because they have the "wrong" rim size, that would leave a potentially significant percentage of the ammo unfit for serious accuracy. I don't know how large a proportion that might be. But without another rifle that could use those "unfit" rounds it would reduce the number of useful rounds in a box of ammo that may cost a fair bit already. So instead of 50 rounds, sorting might tell you that you have only 40 or 35 good rounds in that box. On the other hand if someone were trying to make bulk ammo shoot like match then it would not matter very much.
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I shot high power rifle with a gentleman by the name of Art Grundy for many years and he was also an avid small bore shooter. Art Past away about five years ago so unfortunately I can no longer interrogate him for tips... anyway... I saw his name on more than one trophy down at Camp Perry. One of which was for small bore.

Anyway I know for a fact that he felt strongly about sorting 22 rounds by rim thickness. He also did some kind of dimensional sorting as well.

I also know that he would go to Camp Perry and buy a couple boxes of the same ammo from multiple lots and then go off and test them for groups.

Once he figured out which lot shot the best, he would go back to the vendor and buy what was left of the lot.

Not many guys shoot out 22 rimfire barrels, but I'm sure Art re barreled his Annie several times over the years.
 
You are on the right track. In the example of two different ammos with similar SD and one having a greater ES, it would make sense to use the ammo with the lower ES. This should theoretically help ensure fewer flyers due to MV differences.

SD can be a very useful figure in assessing ammo. The lower the SD is in a sample, the greater the number of rounds that will have an MV closer to the average MV of the ammo in that sample. In other words, if the average MV was 1080 fps, more rounds of that sample of ammo will have an MV close to 1080 fps with a few on the extreme. On the other hand, a sample of ammo with a higher SD and with the same ES means that more of the ammo is closer to either end of the ES. The average MV can be the same, but there is greater variation in MV. Same ES, but differently performing ammo.

To throw a kink into all of this is that the ammo with the lowest ES and lowest SD ought to theoretically perform the best in the rifle in question (the same ammo may behave differently in another bore). The key is theoretically because the chronograph results don't necessarily predict which ammo will in practice shoot the best. In other words, the best chronograph results don't always produce the best results on the target downrange.
 
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