Define a 1MOA rifle

[Tim.243]

so the human factor was the error as I could not repeat the other 2.
Fact...

I’m sorry, I disagree. 3 shots with two touching and one slightly further away is so invalid statistically that you cannot say that the only reason the 3rd wasn’t touching is down to human error. I wasn’t going to point this out until I saw you put ‘Fact’ behind something that isn’t a fact
[/QUOTE]
I don't care....

 

[Mungo]

Agreed we should remove as much as possible. Also agree with Mungo, most people's 2-3 shot strings for reloading velocity or accuracy is far too small. I tried to strike the balance between cost and data accuracy by doing 10 shot strings for velocity.

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The relationship between charge and velocity is reasonably predictable - in fact, consistent enough that things like Quickload can work very well.

It’s the relationship between velocity and accuracy that’s much, much less predictable!

 

[Mungo]

I’m sorry, I disagree. 3 shots with two touching and one slightly further away is so invalid statistically that you cannot say that the only reason the 3rd wasn’t touching is down to human error. I wasn’t going to point this out until I saw you put ‘Fact’ behind something that isn’t a fact

I don't care....
[/QUOTE]

Best change your signature line then.

 

[Mungo]

Most people, and I’d include myself in this, don’t really understand statistics.
I’m constantly amazed at my peers commenting on academic or scientific papers but when pressed it’s clear they don’t understand the statistical methods used to derive the papers conclusions.

You’d be amazed at how many people writing the papers don’t either…

 

[Tim.243]

I don't care....

Best change your signature line then.
[/QUOTE]

Three things, one I will leave it in place, you won't find an answer to what you want in practical terms and last but not least you will shortly find something else like re inventing the wheel

 

[RCS Deer Management]

To answer the original question I believe that a 1moa rifle is one that with its chosen load shoots ALL shots under 1moa. I would choose the range to be 100m or yards as this tends to be what is meant by most people and the group dispersion should be linear as long as velocity ES is low and the bullets are properly stablised. Sample size would have to be large enough to give an accurate representation yet low enough to be practical. I think that 30 rounds is considered to be a good representation of what a rifle is capable of. Hornady have several podcasts on this topic

 

[Heym SR20]

@Mungo have a look at how military / police agencies etc define accuracy standards and specifications.

They used good sized sample - 20 odd cartridges and expect a high percentage to fall with a certain defined target size.

Just about any rifle will shoot a MOA 3 shot group, provided you shoot plenty of groups.

However a true MOA rifle should be able to shoot 95% of bullets into a 1 MOA target with a min sample size of 10,20 or 100.

You are the stats specialist so you would be able to pick a sample size.

 

[Mungo]

Best change your signature line then.

Three things, one I will leave it in place, you won't find an answer to what you want in practical terms and last but not least you will shortly find something else like re inventing the wheel
[/QUOTE]

Best change your signature line then.

Three things, one I will leave it in place, you won't find an answer to what you want in practical terms and last but not least you will shortly find something else like re inventing the wheel
[/QUOTE]

I have found an answer - the people who actually engaged constructively with this rather than prancing about like an attention deprived 4 year old gave a completely practical and robust enough solution that will do what I need it to.

You never even tried to give a sensible answer.

But that’s fine, I understand you’re far too busy solving Real World Problems. Odd that while doing so you still have time to post irrelevant noise on here…

 

[Mungo]

@Mungo have a look at how military / police agencies etc define accuracy standards and specifications.

Turns out they use a lot of different standards…

 

[Tim.243]

Three things, one I will leave it in place, you won't find an answer to what you want in practical terms and last but not least you will shortly find something else like re inventing the wheel

Three things, one I will leave it in place, you won't find an answer to what you want in practical terms and last but not least you will shortly find something else like re inventing the wheel
[/QUOTE]

I have found an answer - the people who actually engaged constructively with this rather than prancing about like an attention deprived 4 year old gave a completely practical and robust enough solution that will do what I need it to.

You never even tried to give a sensible answer.

But that’s fine, I understand you’re far too busy solving Real World Problems. Odd that while doing so you still have time to post irrelevant noise on here…
[/QUOTE]

 

[Loler UK]

Simply apply 3Sigma to a large enough sample. Plenty of case law in favour of 3SR.

 

[Mungo]

Simply apply 3Sigma to a large enough sample. Plenty of case law in favour of 3SR.

So you reckon that 99.7% of shots would need to be inside an inch?

 

[Heym SR20]

Turns out they use a lot of different standards…

Suspect as much

 

[Loler UK]

So you reckon that 99.7% of shots would need to be inside an inch?

No that's not how the 3SR works. In my fictional dataset of 100 shots if one shot were 1.6moa and several 1.1/1.2 it fails the test but change that single shot to 1.5 with the same number of 1.1 & 1.2 moa and it passes the rule. the mean for my fictional dataset was 0.614moa.

I'd suggest that, were this hypothetical not clearly defined "1 moa" guarantee at point of sale to be tested in court the rifle could be shot from a test rig / lead sled to illuminate the shooter as the rifle was guaranteed, not the shooter.

The more interesting argument would be over the ammo, would it be reasonable for a manufacturer to test using custom ammo? or should 5 batches of factory 20 be shot?

I Have significant experience in applying the rule to MBS's not rifles but I think the rule would be considered appropriate by most judges.

 

[billgatese30]

No that's not how the 3SR works. In my fictional dataset of 100 shots if one shot were 1.6moa and several 1.1/1.2 it fails the test but change that single shot to 1.5 with the same number of 1.1 & 1.2 moa and it passes the rule. the mean for my fictional dataset was 0.614moa.

I'd suggest that, were this hypothetical not clearly defined "1 moa" guarantee at point of sale to be tested in court the rifle could be shot from a test rig / lead sled to illuminate the shooter as the rifle was guaranteed, not the shooter.

The more interesting argument would be over the ammo, would it be reasonable for a manufacturer to test using custom ammo? or should 5 batches of factory 20 be shot?

I Have significant experience in applying the rule to MBS's not rifles but I think the rule would be considered appropriate by most judges.

Is that because 1.6 falls outside a particular confidence interval whereas 1.5 falls within that interval?

 

[Loler UK]

Is that because 1.6 falls outside a particular confidence interval whereas 1.5 falls within that interval?

Correct, As unfair as the 3 standards may seem applied to rifle group data to some people it'd be the standard I applied unless the 1MOA term had it's own clearly defined standard.

Ironically if I twist the fictional data string slightly we can see a mean group size decreasing to 0.536 moa fail the 3sig 1MOA test with a single shot at 1.45MOA. So what someone may define as a better grouping rifle is actually a worse grouping rifle, if you get me? The tighter group with a low SD makes the flyer all that much more significant

The whole point of the 3SR is it clearly measures the significance of 'flyers' relative to the sample.

The proof house / CIP also use a similar rule when they test our ammo for pressure, so although your mean P max may be well within the standard it can fail the statistical confidence standard. I bet they've had to deal with some very angry people over the years lol.

I'd imagine that to the non-professional 50 shots all falling within an ES of 1" probably seems fairer but if tested in court I'd not sure a judge would see it that way.

 

[Dalua]

My thoughts on this fascinating thread so far:
1. If a rifle is described as MOA at 100yds, then its shots with the appropriate ammunition should fall within 1MOA at 100yds.
2. Where does the 'Figure of Merit' fit in here, if at all? I've read of it in old text-books, but couldn't really get my head round it.
3. The F-Class target was mentioned. This target was AFAIK invented because the Effers were gettting too many V-Bull possibles on the TR target. As I understand it, the TR target is designed as an instrument to distinguish between skill and chance in that discipline, and its size is from time to time adjusted accordingly. The F-Class target, on the other hand, seems to be as it is because someone thought an MOA-based target was a good idea - rather than to help tell the difference between the better shooter and the luckier one.

 

[billgatese30]

Correct, As unfair as the 3 standards may seem applied to rifle group data to some people it'd be the standard I applied unless the 1MOA term had it's own clearly defined standard.

Ironically if I twist the fictional data string slightly we can see a mean group size decreasing to 0.536 moa fail the 3sig 1MOA test with a single shot at 1.45MOA. So what someone may define as a better grouping rifle is actually a worse grouping rifle, if you get me? The tighter group with a low SD makes the flyer all that much more significant

Similar to the principle I suggested whereby anything outside of 3SD was considered special cause amd removed from the dataset. The better the SD the smaller that deviation would have to be to be considered special cause.

 

[Mungo]

No that's not how the 3SR works. In my fictional dataset of 100 shots if one shot were 1.6moa and several 1.1/1.2 it fails the test but change that single shot to 1.5 with the same number of 1.1 & 1.2 moa and it passes the rule. the mean for my fictional dataset was 0.614moa.

I'd suggest that, were this hypothetical not clearly defined "1 moa" guarantee at point of sale to be tested in court the rifle could be shot from a test rig / lead sled to illuminate the shooter as the rifle was guaranteed, not the shooter.

The more interesting argument would be over the ammo, would it be reasonable for a manufacturer to test using custom ammo? or should 5 batches of factory 20 be shot?

I Have significant experience in applying the rule to MBS's not rifles but I think the rule would be considered appropriate by most judges.

Thanks! I shall go think.

What is an MBS?

 

[kenbro]

Thanks! I shall go think.

What is an MBS?

Modular System of Ballistic Protection.