View Full Version : 30 shot BLK group
Here is a 30 shot group with the UMC ammo, at 100 yards. Notice that if it were a 3 shot group, it would be 1/4 MOA (that is why 3 shot groups are BS).
http://img836.imageshack.us/img836/2245/umc30shot100yds.jpg
Any details on the rifle you were using?
I was under the impression this caliber was mainly for CQB
And unstable at farther distances. Seems I was wrong and now
see my money leaving my wallet...
Can you post a quarter for scale?
Can you post a quarter for scale?
That double cluster on the right(two groups of two) would be covered by a quarter by referencing the .30 hole size as a guide.
If that's a standard AR barrel, with whatever optic from a rest with "ball" ammo, I would say, good to go.
ThreeFingerPete
12-18-11, 22:55
It would only be a 1/4 MOA group if you fired three consecutive shots into a 1/4 MOA group. Anything beyond that is speculation.
That is my point. All 3 shot groups are speculation and worthless for comparison purposes.
You can take the three farthest shots or 3 closest shots from this 30 shot group, and either could have been a 3 shot group. That is no more speculation than if you fired three shots consecutively because the true distribution pattern does not start to emerge until about 30 shots.
ThreeFingerPete
12-19-11, 08:29
In my experience, umc ammo is inconsistent. Add the fact that the gun was not in a ransom rest to eliminate shooter variables and your findings have little merit; other than "you shot that group with that gun on that day." That combo may have been a 4moa combo, but it's very possible that the gun shoots 2moa or better.
mkmckinley
12-19-11, 09:06
That combo may have been a 4moa combo, but it's very possible that the gun shoots 2moa or better.
For 30 rounds? WTF are you talking about?
SomeOtherGuy
12-19-11, 09:28
In my experience, umc ammo is inconsistent.
That probably is true for a lot of the cheap-as-possible UMC. I'm guessing you haven't been following the 300BLK discussion as Robert has made it clear that the 300BLK UMC ammo is being made to a fairly high quality standard in all respects.
Add the fact that the gun was not in a ransom rest to eliminate shooter variables and your findings have little merit; other than "you shot that group with that gun on that day." That combo may have been a 4moa combo, but it's very possible that the gun shoots 2moa or better.
I don't follow. Shooter variables would make the group worse, not better. It's not as if the shooter can know the variables for each cartridge to compensate for them and somehow make the group better than it would have been from a machine rest. To me this looks like an illustration of "this gun and ammo was at least this good on one day."
BTW, while it's been a long time since I took statistics, I vaguely remember being taught that depending on the distribution of the data, the data set didn't become statistically significant until, on average, 30 test points.
ThreeFingerPete
12-19-11, 14:38
My point was that the "three shot groups are bs" statement doesn't hold water. He said that if it were a 3 shot group that it could have been 1/4 moa, which makes no sense unless 3 consecutive shots were that close. ( I dont see numbering on the target)
My point was that the "three shot groups are bs" statement doesn't hold water. He said that if it were a 3 shot group that it could have been 1/4 moa, which makes no sense unless 3 consecutive shots were that close. ( I dont see numbering on the target)
Agreed, my standard for "accuracy of rifle" is five, five shot groups. Granted, doing my part is the hard part, and I don't actually know the accuracy of my rifles, though I do speculate.
Here is a 30 shot group with the UMC ammo, at 100 yards. Notice that if it were a 3 shot group, it would be 1/4 MOA (that is why 3 shot groups are BS).
Nice group. Sorry if I missed this, but what is the diameter of the red circle? Looks like ~3" based on the size of the holes.
My point was that the "three shot groups are bs" statement doesn't hold water. He said that if it were a 3 shot group that it could have been 1/4 moa, which makes no sense unless 3 consecutive shots were that close. ( I dont see numbering on the target)
Three shot "groups" don't tell us enough to try to predict where the next shot will land. The point of shooting groups is to have an idea where your shots will go, with the group size being the margin of error.
Because the dispersion is random, any three of those shots put together could be your three shot group. Or to put it another way he could shoot three shot groups until he randomly got three touching, or got three of the shots furthest apart.
These could be used to show how great or terrible the rifle shoots depending on which one he posted, but all of those three shot groups will fall within the thirty round group if you overlay them.
That is my point. All 3 shot groups are speculation and worthless for comparison purposes.
You can take the three farthest shots or 3 closest shots from this 30 shot group, and either could have been a 3 shot group. That is no more speculation than if you fired three shots consecutively because the true distribution pattern does not start to emerge until about 30 shots.
By the portion above highlighted: Do you mean to say that the rifle has stabilized by 30 shots, or that the rifle will show itself (warts and all) or that this dispersion pattern will begin to repeat itself?
I am taking your statement to mean the worst precision/accuracy result will have been exposed by the completion of 30 rounds for the rate of fire and ambient conditions. Hope I am close...
Thank you
chavez_e_chavez
12-21-11, 17:56
looks good in my book and im blind.....
Todd is correct, as usual.
I am taking your statement to mean the worst precision/accuracy result will have been exposed by the completion of 30 rounds for the rate of fire and ambient conditions. Hope I am close...
It's not really the worst, just the truth. Once the number of rounds is enough to actually be a good sample size (that number is not 3) you know the next round you fire will fall within it.
It's not really the worst, just the truth. Once the number of rounds is enough to actually be a good sample size (that number is not 3) you know the next round you fire will fall within it.
I am in total agreement with this perspecitive regarding the above group.
So few of the general shooting public realize that any first shot, or any shot really, can be within the area of a 30 to 100+ shot group (30 just starts to fill out the distribution area).
Also I may be the first manufacturer to ever release a 30 shot ammo test group. No one else will, because they are terrified that people will lack the knowledge to interpret it.
Instead they fire a dozen 3-shot groups and show the single best one, which I find offensive. Know what else I find offensive? Accuracy guarantees (universally based on 3 shot groups).
The only accuracy guarantee I was impressed by how it was written up was the M24. It was something like average mean radius of 5, 10 shot groups at 200 yards.
Mr Silvers, I will be in Bill Wisemans booth at SHOT, please stop by and chat if time permits
skullworks
12-22-11, 03:31
For your reading pleasure: Statistics Is Not A Dirty Word (http://www.shootingtimes.com/2011/01/04/ammunition_st_statistics_200810/).
To expand on what is mentioned in the article; mathematics (statistics to be exact) tells us that a 3-shot group will only give us 87.5% confidence and a 5-shot group will give us 96.9%. A 7-shot group on the other hand will provide 99.2% confidence; so obviously a larger sample size is better. Of course, this is all on paper (as in drafting paper - not target paper ;)). However, as you know, shooting a full mag for grouping opens us up to additional factors that we may not even see at 7 shots (as heat enters the picture where it might not have played a part during the smaller sample groups) - and these are results that would be of even greater interest to those of us who tend to shoot quite a few rounds at a time (for a sniper group size can often be irrelevant as it is the accuracy of the CBS - ie the location of the 1-shot group - that is of the greatest interest).
Also, in the world of shooting and ballistics we can often fool ourselves by testing the wrong things (or rather by performing the wrong tests). An example would be to shoot a .338 Lapua for groups at 50 or 100 yards - where it often will be outperformed by less whiz-bangy cartridges - when we really should be testing at 600 meters or more.
Also, in the world of shooting and ballistics we can often fool ourselves by testing the wrong things (or rather by performing the wrong tests). An example would be to shoot a .338 Lapua for groups at 50 or 100 yards - where it often will be outperformed by less whiz-bangy cartridges - when we really should be testing at 600 meters or more.
Not only within different cartridges. Also with different barrel length for same cartridge. Friend was testing Sako TRG-22 (660mm barrel) and Tikka T3 Tactical (506mm barrel) out of special testing fixture with all gizmos around (Doppler radar, trajectory analyser and what not). With same sniper grade ammo (testing was for military) showed that T3 is more accurate than TRG-22 up to 300m, then TRG-22 start to shoot tighter than T3 over this distance.
BTW I know of "serious" gun writer who use to shoot 3 rounds group ("becouse more is good only for Internet, real sniper or hunter does not need more") until he finds one that supports his point. This guy has always sub-MOA groups from crappy rifles, with Chinese scope (with his own designed reticle!) and Russian steel cased .223 55gr Barnaul.
Eurodriver
12-22-11, 06:22
So few of the general shooting public realize that any first shot, or any shot really, can be within the area of a 30 to 100+ shot group (30 just starts to fill out the distribution area).
Also I may be the first manufacturer to ever release a 30 shot ammo test group. No one else will, because they are terrified that people will lack the knowledge to interpret it.
Instead they fire a dozen 3-shot groups and show the single best one, which I find offensive. Know what else I find offensive? Accuracy guarantees (universally based on 3 shot groups).
Unfortunately, you are entirely correct.
3 shot 1/4 MOA groups impressed the Old Timers and get them to spend money.
blasternank
12-22-11, 22:06
nice!
So few of the general shooting public realize that any first shot, or any shot really, can be within the area of a 30 to 100+ shot group (30 just starts to fill out the distribution area).
Also I may be the first manufacturer to ever release a 30 shot ammo test group. No one else will, because they are terrified that people will lack the knowledge to interpret it.
Instead they fire a dozen 3-shot groups and show the single best one, which I find offensive. Know what else I find offensive? Accuracy guarantees (universally based on 3 shot groups).
The only accuracy guarantee I was impressed by how it was written up was the M24. It was something like average mean radius of 5, 10 shot groups at 200 yards.
How about firing 10 shots, saving the target and shooting the same target 2-3 times a month for 3 months. I personally value consistency over the ability to shoot that one "1/4 inch group" out of 10 groups on a mild windless day in May. If that 30 round group RSilvers shot was from one of the AAC uppers that is not bad at all. If you could do that 10 times in a row on 10 different outings that is great! For me the other part of the equation is the optic/mount, toss your rifle in the truck and keep bringing it back to the range and shooting that same target, take it hunting, carry it and keep bringing it back to shoot the same target, I like to be confident in the equipments consitency. I am just a hunter, but I like stuff to work, those things that don't go down the road.
Is it a correct interpretation of that group that the sight needs to be adjusted about 1-1.5" to the right?
It's not really the worst, just the truth. Once the number of rounds is enough to actually be a good sample size (that number is not 3) you know the next round you fire will fall within it.If I understand correctly, the total 30 rounds represents 100% of where the shots can be expected to land, and the central 15-20 of them is where 75-80% of them will land and thus where the zero should be adjusted to fit. Thus it's futile to chase one's scope around the paper based on 3 or even 5 shot groups because inevitably the 4th or 6th shot will make you think you're wrong and try to adjust according to it.
Excellent work, Mr. Silvers, and I hope others will follow suit and do more of the same. This is much, much more useful than anything I've seen before from others and definitely gives me a lot of perspective on my goals with my rifles. I'm going to apply this to my practice and evaluations from now on.
Yes, but the way to be sure is to use software to locate the center of the group.
So few of the general shooting public realize that any first shot, or any shot really, can be within the area of a 30 to 100+ shot group (30 just starts to fill out the distribution area).
Also I may be the first manufacturer to ever release a 30 shot ammo test group. No one else will, because they are terrified that people will lack the knowledge to interpret it.
Instead they fire a dozen 3-shot groups and show the single best one, which I find offensive. Know what else I find offensive? Accuracy guarantees (universally based on 3 shot groups).
The only accuracy guarantee I was impressed by how it was written up was the M24. It was something like average mean radius of 5, 10 shot groups at 200 yards.
The basic problem in discussing shot groups is that it requires a somewhat peculiar mathematical language if a person is to adequately express the facts. The simplest way to describe the phenomena, as you are likely aware, would be to count the number of shots that land at bucketed distances from the "X". All other factors being kept equal, those numbers would describe a normal distribution. Since a rifle target has both height and width, a more complete view would be a 3D plot where the vertical dimension represents the number of shots in that location. Picture a haystack. The more pointed the haystack, the more accurate the rifle and its load; the flatter the haystack, the more random the spread of shot. While 3 or 5 shots thru the same hole certainly indicates a propensity for accuracy, it does not tell the entire tale. These two comparisons of 5.56 ammunition show 30-shot overlays that can be examined more completely than the usual target picture:http://www.box.com/shared/static/hgdpmkhkw0.jpg , http://www.box.com/shared/static/61n5als9sm.jpg
Picture a haystack. The more pointed the haystack, the more accurate the rifle and its load; the flatter the haystack, the more random the spread of shot. While 3 or 5 shots thru the same hole certainly indicates a propensity for accuracy, it does not tell the entire tale. These two comparisons of 5.56 ammunition show 30-shot overlays that can be examined more completely than the usual target picture:http://www.box.com/shared/static/hgdpmkhkw0.jpg , http://www.box.com/shared/static/61n5als9sm.jpg
Is statistically calculated mean radius (as on presented pictures) good way to present this difference? Of course to have it mean something, statistically significant probe must be used. Like 30 shots for example.
I do actually use mean radius, as OnTarget can calculate it nicely for me :agree:
Is statistically calculated mean radius (as on presented pictures) good way to present this difference? Of course to have it mean something, statistically significant probe must be used. Like 30 shots for example.
I do actually use mean radius, as OnTarget can calculate it nicely for me :agree:
Yes - that is what I do for internal testing - mean radius (good and easier to understand) or radial standard deviation (best but slightly more abstract).
My dream is where no one can make an accuracy claim without something like how the EPA does fuel economy. Govt tests it, and it would be average mean radius - 30 shot group at 100 yards, 10 guns tested.
Something I think about when referring to group size is, well, the group size.
With each shot, your point of aim on the target gets more and more distorted.
After three shots, you no longer have a crisp 1 inch dot to focus on. So you may be aiming dead center of a 1" dot for the first couple rounds, but then you'll be aiming dead center of half of that dot, or maybe just the ragged hole you have left.
I make up for this by adjusting the elevation on my optic so my rounds impact 2" low. This way, even after ten shots on paper, I still have a crisp spot on the target to aim at.
Just rambling.
Robert and Todd--Thanks for speaking the TRUTH! 30 rd group is a good start, as is averaging 5 x 10 rd groups. An adequate sample size is the only way to begin to see what the true dispersion pattern will be. Using 3 rd and even 5 rd groups is bogus, as are any "guarantees" of rifle accuracy using such "groups".
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