I'll Post This Here - Hornady's Podcast #50. I thought it was one of their best, but some reloaders might not like what they see....

[Milo 2.5]

Data on group size but no statistical data and analysis on what contributed to those group sizes.

There is plenty of myth and lore in the BR world and reloading.

Not trying to start anything here, but 2.5" five shot groups at 1K, not really sure why statistical data or analysis is needed. If the shooters are out of Deep Creek range and claim positive compensation, that won't fly here so why bother?
On myth and lore, aren't we front and center of this right here?

 

[Tx_Aggie]

Not trying to start anything here, but 2.5" five shot groups at 1K, not really sure why statistical data or analysis is needed. If the shooters are out of Deep Creek range and claim positive compensation, that won't fly here so why bother?
On myth and lore, aren't we front and center of this right here?

Are they all 2.5” 5 shot groups at 1000?

Or is it just a 2.5” “Agg” at 1000?

Not that the latter isn’t still impressive, but it’s not even remotely the same thing.

Especially if each group is measured independently and with no concern as to whether or not they are all even centered around the same aim point.

 

[kthomas]

Not trying to start anything here, but 2.5" five shot groups at 1K, not really sure why statistical data or analysis is needed. If the shooters are out of Deep Creek range and claim positive compensation, that won't fly here so why bother?
On myth and lore, aren't we front and center of this right here?

But what created that 2.5" group at 1,000? How much did each piece of that puzzle contribute to that?

2.5" at 1,000 is amazing shooting and ammo quality. But what matters and what doesn't? Those results at 1,000 don't answer those questions.

None of us really know. Because it hasn't really been tested in any detailed way. We are left to our own observational analysis, which is prone to many faults.

 

[ma smith]

Are they all 2.5” 5 shot groups at 1000?

Or is it just a 2.5” “Agg” at 1000?

Not that the latter isn’t still impressive, but it’s not even remotely the same thing.

Especially if each group is measured independently and with no concern as to whether or not they are all even centered around the same aim point.

Nobody cares about ES once N=Large, since once your averages are good enough, in terms of statistical power, that the ES becomes outliers. With N=large datasets, ES is a resevoir of garbage data.

This is a very basic concept that should have been explained clearly.

Just my $0.02c

 

[Tx_Aggie]

Nobody cares about ES once N=Large, since once your averages are good enough, in terms of statistical power, that the ES becomes outliers. With N=large datasets, ES is a resevoir of garbage data.

This is a very basic concept that should have been explained clearly.

Just my $0.02c

I’m just trying to understand what benchrest scoring represents.

How large of a sample is a Benchrest group aggregate? 6 individual “matches” of 5 shots each?

Mostly I hear it referred to in terms of what is required to win a match, meaning it’s representative of the best performance on a given day. Which is a much smaller sample than the expected performance of a benchrest rifle over the life of a barrel.

It also seems like there’s not an attempt to reference any standardized point of aim across groups (they’re just measured for group ES and recorded), and no requirement that a shooter maintain the same point of aim throughout the course of shooting an individual group. But groups still seem to be averaged together as if they could be laid on top of one another.

Do I have that right?

 

[spife7980]

It also seems like there’s not an attempt to reference any standardized point of aim across groups (they’re just measured for group ES and recorded), and no requirement that a shooter maintain the same point of aim throughout the course of shooting an individual group. But groups still seem to be averaged together as if they could be laid on top of one another.

Do I have that right?

Right? Not really, there are several different disciplines of benchrest. It primarily comes down to Group vs Score. One is how small your groups are on average, the other is how close to the actual center you get total.

All require the best shooting rifle you can get. Making small circles (group size with the 6ppc) vs hitting small circles (score with a 30br) still requires being able to shoot really small to be remotely competitive.

 

[timintx]

Data on group size but no statistical data and analysis on what contributed to those group sizes.

There is plenty of myth and lore in the BR world and reloading.

Dude , you will argue with a tree , there is tons of data , you just refuse to believe it , everybody is analyzing every group intently , every shot statistically, wind conditions, mirage , gun handling , etc . Constantly noting changes , etc . And for everybody saying every shooter shoots 1-2 groups and calls it good in the real world that never happens . So why do you guys keep saying all of this stuff happening when it is not? I mean come on guys , every competition shooter puts in his due diligence. Your just saying no one understands it is is all wrong . Why ? Your points would be better taken if you stop insulting the very shooters your trying to help

Timintx

 

[kthomas]

Dude , you will argue with a tree , there is tons of data , you just refuse to believe it , everybody is analyzing every group intently , every shot statistically, wind conditions, mirage , gun handling , etc . Constantly noting changes , etc . And for everybody saying every shooter shoots 1-2 groups and calls it good in the real world that never happens . So why do you guys keep saying all of this stuff happening when it is not? I mean come in guys , every competition shooter puts in his due diligence. Your just saying no one understands it is is all wrong . Why ? Your points would be better taken if you stop insulting the very shooters your trying to help

Timintx

These competitors undoubtedly are great shooters and make great ammunition. No one is insulting them in their skillsets.

But all the data collected is through observation and spread through anecdotes. As good as the ammo being produced is, so far there isn't a way of quantifying what steps lead exactly to what outcomes.

That's because testing in such a manner is extremely time and resource intensive to do. Much more than any one individual can take on. So we as shooters have to rely on observational and anecdotal evidence, which isn't very reliable way of analyzing data.

 

[Milo 2.5]

Are they all 2.5” 5 shot groups at 1000?

Or is it just a 2.5” “Agg” at 1000?

Isn't the Agg the sum of the groups shot for the day, or match? Being around 1.3" is the record during a comp, I think all groups must be consistent. I don't know shit about BR, but don't think low Agg is a factor in winning the match, that is X's and 10's.
I think<big if, that you can win the Agg with all shots in the 5 ring, all day, with shitty accuracy.
I don't know, but I believe we as a whole are really overthinking all this crap.

 

[Milo 2.5]

But what created that 2.5" group at 1,000? How much did each piece of that puzzle contribute to that?

2.5" at 1,000 is amazing shooting and ammo quality. But what matters and what doesn't? Those results at 1,000 don't answer those questions.

None of us really know. Because it hasn't really been tested in any detailed way. We are left to our own observational analysis, which is prone to many faults.

I actually got booted off Accurate Shooter, not over load dev, lmao. But I learned a lot, through the forum, and pm's, with some guys that have won and win.
All said, tune your load at the distance you compete at, and at no time when walking it back closer to you will you be disappointed. You need patience and nice days to tune at 1K, and it is not for everyone, but on the occasions I have done it, they were not wrong.
I try not to criticize others methods, and am sure I have faltered at times, but casual hunters trying to save 80 bucks on 3 boxes of ammo have the most to learn. Us here, whether agreeing or not, are heading towards positive results.

 

[kthomas]

I actually got booted off Accurate Shooter, not over load dev, lmao. But I learned a lot, through the forum, and pm's, with some guys that have won and win.
All said, tune your load at the distance you compete at, and at no time when walking it back closer to you will you be disappointed. You need patience and nice days to tune at 1K, and it is not for everyone, but on the occasions I have done it, they were not wrong.
I try not to criticize others methods, and am sure I have faltered at times, but casual hunters trying to save 80 bucks on 3 boxes of ammo have the most to learn. Us here, whether agreeing or not, are heading towards positive results.

Obviously some knowledgeable and good shooters and reloaders on there. I've learned a lot on that forum, and I'm not trying to take anything away from the BR crowd or anyone else.

I'm just pointing out the realities that we as reloaders and shooters are trying to draw definitive conclusions from very incomplete data sets.

 

[37L1]

Shooter: Great group!

Statistician: It's only 5 shots .

Me: So it's not a great group?

LMFAO. . .

 

[timintx]

Shooter: Great group!

Statistician: It's only 5 shots .

Me: So it's not a great group?

LMFAO. . .

Exactly right .I had a 1000 yard target with 3 bullets touching in the middle and 16 inches to the right I had 2 bullets touching , my evaluation was that the gun was in tune but I need to read the wind next time. I sure was proud of that 16 inch group and I learned a lot in only 5 shots , needless to say the groups were much better after that lol. It is amazing what you can learn from one group at a match and not be statistically valid lol.

Timintx

 

[Barelstroker]

So I tested this stuff this weekend just to see if theres something to it. I dont think I learned anything just burned 60 rounds of components. Two 30 shot groups. I guess I should have shot 50 round groups then thy would open up. 100 yards 6 dasher hawk hill heavy comp.

What were you expecting to see?
Using a higher sample number elevates your probability level.
From the pics you posted, you can now rightly brag that you do indeed have a true 1/2 MOA rifle/shooter system.
So after expending all that expensive ammo, you can at least know that the testing you did, does, in reality, reflect what your rifle/shooter system is likely to continue to shoot.
In a nut shell, had you claimed that your rifle was a 1/2MOA gun then, proceeded to show 3 or 4, 3 shot groups, I wouldn't have put much in that.
In contrast, you show what I believe to be a significant number of samples to back your 1/2 MOA claim.
So, you may not see much difference between 5 shot groups & 2 x 30 shot groups but, I most certainly did.

 

[JAS-SH]

What were you expecting to see?
Using a higher sample number elevates your probability level.
From the pics you posted, you can now rightly brag that you do indeed have a true 1/2 MOA rifle/shooter system.
So after expending all that expensive ammo, you can at least know that the testing you did, does, in reality, reflect what your rifle/shooter system is likely to continue to shoot.
In a nut shell, had you claimed that your rifle was a 1/2MOA gun then, proceeded to show 3 or 4, 3 shot groups, I wouldn't have put much in that.
In contrast, you show what I believe to be a significant number of samples to back your 1/2 MOA claim.
So, you may not see much difference between 5 shot groups & 2 x 30 shot groups but, I most certainly did.

Agreed!

I just finished a similar test sequence last week. It was a side result of my obsession on truing my 6mm ARC bolt gun so that I could feed the 4DOF calculator really good info. I knew that truing my rifle was going to involve a lot of shots and measurements. So, I decided to combine the truing with testing the precision capability of the rifle system over a lot of shots, which of course includes my ability to shoot!

I started by slapping on my new Christmas present Magneto Speed on the rifle and shooting two 10-shot groups and averaged those for velocity readings. This said, being new to the MS I immediately noticed that based on my prior shooting experience with this rifle, the groups opened up and they had a lower point of impact. This rifle does not like the MS hanging on the end of the barrel.

Here’s the first 10 shot group. Shot #1 was the cold bore shot. The extreme spread was .741 MOA @ at a measured 106 yards for 10 shots. Always check your 100-yard range actual distance! Red lines are .1 mils apart.

If it wasn’t for the two outliers, shot #1 and #5 the group would have been smaller, but I count everything!

I then took the MS off the barrel and shot two additional 10-shot groups for zero and went home. For calculating the zero I measured the shots with calipers to measure azimuth and elevation for each shot then averaged those and recorded the numbers.

The next time at the range I spent a good amount of time shooting and adjusting the scope (Vortex Razor 4.5-27), etc. Tough scope to adjust…

After getting a confident zero, I loaded six rounds in the mag, this was part of another planned test, and then shot two 3-shot groups instead of a single six shot group. This was by design. I wanted to see the difference between 5-6 shot groups vs. just 3 shots. You’ll see that below.

I came up with a slightly low zero average (.014 inches low) and kept that. I think in the future I might add .1 mil up (.36 inches or so). I rather be a little high than low because I always aim a little bit low to more clearly see the center of very small target aim points – how it works for me at longer ranges.

So here are the two 3-shot groups – those were fired in the shown sequence without getting off the rifle with, just a slight move to the right to a fresh target:

Nice groups, with the last one at .228 MOA being smaller than caliber (remember this was shot at 106 yards so it’s not inches at 100).

And then, I went into Photoshop and combined both those targets into one and took that measurement. SO, the final tally on dispersion for the combined 6-shot group was .456 MOA at 106 yards. Here’s that montage:

AND THAT, is as good as it gets for me behind a Badrock/Defiance Machine rifle build, with 6mm ARC Hornady 108 ELD Match FACTORY ammo.

 

[JAS-SH]

After a benchrest match there is plenty of statistics. The whole match is all about statistics and is the only discipline that requires true .250 or lower aggs match after match is 100 yd benchrest just to be in the top 10 most of the time. A 6 target agg of .170 -.190 area is quite common to win most all of the time at least in my opinion, and then the grand agg which is the sum of two gun agg in each class [heavy 10 shot groups and light five shot groups.]and at 100 and 200 yards. It is a true art and does happen quite frequently. 1000yd benchrest has a requirement of .2-.3 agg to win. , I have seen 2 target aggs as low as 2.1 inches at 1000yds and 2.3-2.9 inch 3 target aggs , now it takes a 2-3 inch agg to win at 1000yd nationals , no other discipline requires that kind of consistent precision to win.

Timintx

The point is about what is statistically probable. And in your post you start talking statistics but then contradict yourself by saying "I have seen 2 target aggs as low as 2.1 inches at 1000yds" Is that a statistic? And, then, "...now it takes a 2-3 inch agg to win at 1000yd nationals..." Another statistic?

Come on now... How often does that happen? I am sure that it's not very often and I'll bet good money on that. That said, and as precise as those rifles are, that is always a probability. The research that I have done shows me that the average for winners is ~ 4.0"+, Which means that some are higher (or smaller) than that. Still great rifle precision, but that's the winners, which by definition is the lowest agg, and not the aggregate of all the competitors for that particular event. That number is much higher, and by the way, said higher number surely includes a number of past winners.

 

[memilanuk]

It's the BR equivalent of "my gun will shoot half moa 'all day long', as long as I do my part". Anything that shrinks that agg (average) is okay to talk about. Anything that expands the agg... shall not be mentioned. Or if, under duress, you actually managed to force them to do so, it's always with 'qualifiers', like it was the wind, or lighting, or a condition moving through, or the gun/load was out of tune... never, ever, something so mundane and plebian as the other part of the statistical average getting it's due.

 

[Haney]

Same bullshitters in any discipline . Take this thread for instance . Deny it all you want, same shit different smell .

 

[timintx]

The point is about what is statistically probable. And in your post you start talking statistics but then contradict yourself by saying "I have seen 2 target aggs as low as 2.1 inches at 1000yds" Is that a statistic? And, then, "...now it takes a 2-3 inch agg to win at 1000yd nationals..." Another statistic?

Come on now... How often does that happen? I am sure that it's not very often and I'll bet good money on that. That said, and as precise as those rifles are, that is always a probability. The research that I have done shows me that the average for winners is ~ 4.0"+, Which means that some are higher (or smaller) than that. Still great rifle precision, but that's the winners, which by definition is the lowest agg, and not the aggregate of all the competitors for that particular event. That number is much higher, and by the way, said higher number surely includes a number of past winners.

No the point is not to see what is probable ,it is to show there is a agg of more than 1or 2 groups and with multiple guns in one match .Give me a break here , you guys preach large and unrealistic statistics and I am willing to bet none of you follow your own 200 shot samples to determine your own loads.I am not saying my gun shoots .250 all day long , but that is the goal and not always the result , so get over it . You sure didn’t mention 100 yard aggs , lol. Every match is different but again the point is not what is probable but what was done to keep the agg as low as possible. You are looking to just start a argument again over unrealistically large shot samples. No shooter is going to shoot a large shot sample and not expect things to change and not adjust . We are constantly changing stuff throughout the matches and the year to retain as low of a agg as possible . No one in this thread has ever said i shoot .250 all day long if you think small samples do not work then great , go ahead and wear out that barrel to get your load and when it changes and you shoot like crap go ahead and blame it on outliers or normal dispersion. I am not swallowing the coolaid , I am going to diagnose each group and adjust accordingly .

Timintx

 

[morganlamprecht]

That’s pretty much been my stance all along…regardless of how many rounds people want to test with

If things need to be constantly changed throughout matches/barrel life to maintain the best groups/tune…which obviously the paper punching BR disciplines rely on…it doesn’t apply to myself shooting hundreds of rounds at steel over a weekend in various locations and various distances

 

[morganlamprecht]

No the point is not to see what is probable ,it is to show there is a agg of more than 1or 2 groups and with multiple guns in one match .Give me a break here , you guys preach large and unrealistic statistics and I am willing to bet none of you follow your own 200 shot samples to determine your own loads.I am not saying my gun shoots .250 all day long , but that is the goal and not always the result , so get over it . You sure didn’t mention 100 yard aggs , lol. Every match is different but again the point is not what is probable but what was done to keep the agg as low as possible. You are looking to just start a argument again over unrealistically large shot samples. No shooter is going to shoot a large shot sample and not expect things to change and not adjust . We are constantly changing stuff throughout the matches and the year to retain as low of a agg as possible . No one in this thread has ever said i shoot .250 all day long if you think small samples do not work then great , go ahead and wear out that barrel to get your load and when it changes and you shoot like crap go ahead and blame it on outliers or normal dispersion. I am not swallowing the coolaid , I am going to diagnose each group and adjust accordingly .

Timintx

Tim, with your experience on the BR side of things…

Could you provide any estimates as to how you think the groups/aggs would change with each piece of equipment removed/swapped? Or too many variables?

Say full whack BR setup, aggs .2s

Remove the flags…aggs go to? .3, .4?

Swap rest for typical bipod? Another +.1?

Swap formed rear bag for a squeeze bag?

Any general ideas as to what the BR aggs would look like shooting the typical guns most people have with rear bag/bipod/no flags?

 

[timintx]

Tim, with your experience on the BR side of things…

Could you provide any estimates as to how you think the groups/aggs would change with each piece of equipment removed/swapped? Or too many variables?

Say full whack BR setup, aggs .2s

Remove the flags…aggs go to? .3, .4?

Swap rest for typical bipod? Another +.1?

Swap formed rear bag for a squeeze bag?

Any general ideas as to what the BR aggs would look like shooting the typical guns most people have with rear bag/bipod/no flags?

What you posted looks pretty accurate to me . I would only be guessing .

Timintx

 

[CK1.0]

@morganlamprecht and @timintx I think you guys are barking up the right tree when you’re talking about taking into consideration all the “other stuff” that contributes to our aggregate/group sizes that’s NOT reloading-related.

I tend to be more of an Occam’s razor type of guy and I try to look for simpler explanations as to why I suck at shooting some days… things like: bad trigger pulls, breathing wrong, not stable, etc…

IMO it’s far more rare than most guys want to admit when something they did in their reloading room actually has/had something to do with their shitty aggregate/groups.

I think there’s a point where we can’t blame the load. If I know I’ve got a gun/load that will print 1/2moa out to 1000+ “if I do my part” and then randomly it doesn’t one day, I try to look in the mirror, not at my rounds lol.

Even though I’m more of a PRS-style shooter using a Harris and Gamechanger, I try to shoot most of my club’s 600/1000yrd BR matches (good hang, always learn something), and I’ve even won more than few relays here and there (whole matches are another story lol). On the drive home I’ve thought about maybe splurging on one of those fancy DimaRS rear bags and/or maybe a beefier bipod for improving my BR scores… but changing/tuning my load? Nope, because it’s not that.

 

[timintx]

@morganlamprecht and @timintx I think you guys are barking up the right tree when you’re talking about taking into consideration all the “other stuff” that contributes to our aggregate/group sizes that’s NOT reloading-related.

I tend to be more of an Occam’s razor type of guy and I try to look for simpler explanations as to why I suck at shooting some days… things like: bad trigger pulls, breathing wrong, not stable, etc…

IMO it’s far more rare than most guys want to admit when something they did in their reloading room actually has/had something to do with their shitty aggregate/groups.

I think there’s a point where we can’t blame the load. If I know I’ve got a gun/load that will print 1/2moa out to 1000+ “if I do my part” and then randomly it doesn’t one day, I try to look in the mirror, not at my rounds lol.

Even though I’m more of a PRS-style shooter using a Harris and Gamechanger, I try to shoot most of my club’s 600/1000yrd BR matches (good hang, always learn something), and I’ve even won more than few relays here and there (whole matches are another story lol). On the drive home I’ve thought about maybe splurging on one of those fancy DimaRS rear bags and/or maybe a beefier bipod for improving my BR scores… but changing/tuning my load? Nope, because it’s not that.

I understand your thinking on that but bear in mind when we have all of the good Benchrest equipment and starting seeing shots drop out the bottom or going out the top say a foot or so , and is not wind related then that indicates a tune issue such as a seating depth problem due to throat erosion .So when the seating depth is lengthened a bit and the squirter stops after that , then I know it worked . The enemy in Benchrest is vertical fliers .

Timintx

 

[JAS-SH]

No the point is not to see what is probable ,it is to show there is a agg of more than 1or 2 groups and with multiple guns in one match .Give me a break here , you guys preach large and unrealistic statistics and I am willing to bet none of you follow your own 200 shot samples to determine your own loads.I am not saying my gun shoots .250 all day long , but that is the goal and not always the result , so get over it . You sure didn’t mention 100 yard aggs , lol. Every match is different but again the point is not what is probable but what was done to keep the agg as low as possible. You are looking to just start a argument again over unrealistically large shot samples. No shooter is going to shoot a large shot sample and not expect things to change and not adjust . We are constantly changing stuff throughout the matches and the year to retain as low of a agg as possible . No one in this thread has ever said i shoot .250 all day long if you think small samples do not work then great , go ahead and wear out that barrel to get your load and when it changes and you shoot like crap go ahead and blame it on outliers or normal dispersion. I am not swallowing the coolaid , I am going to diagnose each group and adjust accordingly .

Timintx

Geez Tim! If I hit a nerve, then I sincerely apologize. That was not my intent.

Some words of advice maybe? In my lifelong profession, when communicating be it using speech or in writing, precision is paramount, the same as with shooting.

Using that analogy, it struck me that the nature of your response to my post, being an unbroken single paragraph 243-word salad, was akin to shooting from the hip. And as we both know, shooting from the hip is not very precise.

That then precludes me from responding to your post specifics because my response would be just a bunch of rhetorical questions that would in all probability (pun intended) inflame the situation even more.

JAS

 

[timintx]

Geez Tim! If I hit a nerve, then I sincerely apologize. That was not my intent.

Some words of advice maybe? In my lifelong profession, when communicating be it using speech or in writing, precision is paramount, the same as with shooting.

Using that analogy, it struck me that the nature of your response to my post, being an unbroken single paragraph 243-word salad, was akin to shooting from the hip. And as we both know, shooting from the hip is not very precise.

That then precludes me from responding to your post specifics because my response would be just a bunch of rhetorical questions that would in all probability (pun intended) inflame the situation even more.

JAS

No worries , and I apologize as well if I seemed to answer with a rude context in my statements . Just irritated at the name calling and misquotes that is prevalent on these forums.

Timintx

 

[MarkyMark007]

john masek is on right track to cut off the bullshit and retarded 0.003'' increments. but he still uses word 'node' and looks for it. but he will learn... i believe in him.

 

[CK1.0]

He only shot 20 rounds.

Not nearly enough to tell the story...

Someone tell F-class John to shoot a whole match with all of his ammo 100 thou off... I bet he'll finish in about the same place he usually would. Shit, he might even do better than usual, since his gun won't change as the throat erodes over the course of the day like it normally would.

 

[Jackomason]

I'll just leave this here....

 

[Barelstroker]

I'll just leave this here....
View attachment 8162382

Yeah, yeah, very pretty.
During my last lot of testing for my 308 Win, I shot the 1st 3 shots into virtually one hole just barely larger than bullet diameter but, I'm not going to waste my time & head off to the BR nationals because, the situation didn't stay that way did it, & that's the entire point.
At very least, 3 shot groups are a mute point. Although they may not say it to your face, a BR or F-class competitor will probably think "Well that's great, where's the rest of the shots"? Three shot groups are meaningless to everyone except manufacturers who supply a 3 shot group target as proof of their rifles 1/2 MOA "GUARANTEE" which I suspect, is where all this 3 shot group nonsense started.

 

[37L1]

Yeah, yeah, very pretty.
During my last lot of testing for my 308 Win, I shot the 1st 3 shots into virtually one hole just barely larger than bullet diameter but, I'm not going to waste my time & head off to the BR nationals because, the situation didn't stay that way did it, & that's the entire point.
At very least, 3 shot groups are a mute point. Although they may not say it to your face, a BR or F-class competitor will probably think "Well that's great, where's the rest of the shots"? Three shot groups are meaningless to everyone except manufacturers who supply a 3 shot group target as proof of their rifles 1/2 MOA "GUARANTEE" which I suspect, is where all this 3 shot group nonsense started.

*moot

 

[Jackomason]

Yeah, yeah, very pretty.
During my last lot of testing for my 308 Win, I shot the 1st 3 shots into virtually one hole just barely larger than bullet diameter but, I'm not going to waste my time & head off to the BR nationals because, the situation didn't stay that way did it, & that's the entire point.
At very least, 3 shot groups are a mute point. Although they may not say it to your face, a BR or F-class competitor will probably think "Well that's great, where's the rest of the shots"? Three shot groups are meaningless to everyone except manufacturers who supply a 3 shot group target as proof of their rifles 1/2 MOA "GUARANTEE" which I suspect, is where all this 3 shot group nonsense started.

I guess I'm just trying to figure out if Hornady is manipulating me with 20 shot groups or if they are manipulating me with 3 shot groups... sounds like a me problem... capitalism is hard.

Don't let the irony go over your head.

 

[Tokay444]

I'll just leave this here....
View attachment 8162382

That’s not a 50 shot group!

 

[Doom]

The podcast was with engineers/ballistic experts not marketing. A more appropriate question would be "How many 3 shot groups" did it take to do this?

 

[Gogga]

An interesting subject. As a newer fullbore rifle shooter my first thought when testing my loads was how much is me and how much is the load? I decided to settle on something that seemed ok and improve my technique before chasing fractions of an inch. My Tikka was supposed to be good for 1 MOA so that's what I decided on as acceptable. I'm still learning and improving, this prone rifle stuff is quite similar but different from pistol shooting, where the biggest variable (you) is more obvious!
My approach was buy good components and assemble them carefully and consistently. I will fine tune later once I feel the gear is limiting my skills, I don't think I'm there yet but I'm finding I get fewer "fliers" which I put down to recoil management (.308) and consistency in position. A much bigger issue is, I hear, primer shipments to the UK for the next 3 years are likely to be minimal to none.

 

[MarkyMark007]

well, you must understand statistics too, you know...

even 3-shot group is statistic! just not confident about next 3-shot group. or average 3-shot group.

but when Erik Cortina shot 10 3-shot groups and average at 0.3 MOA, and non of those groups are super large, that's very confident outcome about that those his groups are AVERAGE 3-SHOT GROUPS !

and if we want to see how precise is his rifle for 50 shots, we can multiply this 3-shot group by factor.

the wrong practice about small sample size is that within 10 3-shot groups we see one tiny at 0.033'' jump, and we think that this is repeatable. this is WRONG.
but if we see all 10 3-shot groups are quite the same, we can be confident that our 3-shot group is AVERAGE.

 

[MarkyMark007]

Are they all 2.5” 5 shot groups at 1000?

Or is it just a 2.5” “Agg” at 1000?

Not that the latter isn’t still impressive, but it’s not even remotely the same thing.

Especially if each group is measured independently and with no concern as to whether or not they are all even centered around the same aim point.

’m just trying to understand what benchrest scoring represents.

How large of a sample is a Benchrest group aggregate? 6 individual “matches” of 5 shots each?

Mostly I hear it referred to in terms of what is required to win a match, meaning it’s representative of the best performance on a given day. Which is a much smaller sample than the expected performance of a benchrest rifle over the life of a barrel.

It also seems like there’s not an attempt to reference any standardized point of aim across groups (they’re just measured for group ES and recorded), and no requirement that a shooter maintain the same point of aim throughout the course of shooting an individual group. But groups still seem to be averaged together as if they could be laid on top of one another.

Do I have that right?

it is quite simple. they have group for one game, and 'agg' for whole match, and 'agg' for whole season.

and of course an 'agg' for whole season is composed from very very tiny groups and some that are quite large. but sample size of 5-shot groups is quite big so and AVERAGE of all those groups are CONFIDENT representation, what is precision of this gun. for 5-shot group.

but if we want to translate this precision to 'hornady' language, we must multiply this agragate of 5-shot group with some factor, so we can see how this gun is shooting 50-shot groups. and we can be very confinent about this, because sample size of 5-shot groups is big.

but on the other hand, only with 'agg' at one match we cant be so confident about rifle precison, because we can have some luck one day and our 5 5-shot groups will be the smallest in whole season.

and especialy with the smallest goup, which win particular game, we cant draw a conclusion about precision, because those groups are the smallest of 5-shot groups of ALL CONTENDERS, and are one time lucky event.

whole year 'agg' is what is statisticaly relevant and confident.

 

[Tx_Aggie]

it is quite simple. they have group for one game, and 'agg' for whole match, and 'agg' for whole season.

and of course an 'agg' for whole season is composed from very very tiny groups and some that are quite large. but sample size of 5-shot groups is quite big so and AVERAGE of all those groups are CONFIDENT representation, what is precision of this gun. for 5-shot group.

but if we want to translate this precision to 'hornady' language, we must multiply this agragate of 5-shot group with some factor, so we can see how this gun is shooting 50-shot groups. and we can be very confinent about this, because sample size of 5-shot groups is big.

but on the other hand, only with 'agg' at one match we cant be so confident about rifle precison, because we can have some luck one day and our 5 5-shot groups will be the smallest in whole season.

and especialy with the smallest goup, which win particular game, we cant draw a conclusion about precision, because those groups are the smallest of 5-shot groups of ALL CONTENDERS, and are one time lucky event.

whole year 'agg' is what is statisticaly relevant and confident.

Based on what you're saying, it seems to me that the concept of an "Agg" is designed cast a rifle (and shooter) in a positive light by focusing on an average instead of the largest group that the rifle has shot on record. Which is all well and good within the realm of benchrest competition.

But I think it's important to emphasize that the use of an average will all but erase the largest groups shot by the rifle as these are likely to be as rare as the smallest groups, and so will be drowned out as noise. The only thing more biased toward an ideal outcome would be only reporting the best groups. Heck, using an average effectively disregards the largest half of individual groups/samples shot by the rifle.

Again I could be wrong here, but there seems to be no effort made to record or report the largest group of the sample, something that would be more evident when using a single large sample, or several large samples. In fact, quite the opposite, as one can just accumulate more small samples to drown out any unfavorable data points.

This tendency to rely on averages is actually using statistics to make a rifle appear to have a higher level of ultimate precision that it might if data were recorded differently.

You give the example of a smaller group being lucky (it's not luck, just probability) and distorting a small set of samples, but being absorbed in a larger set. The opposite is also very much true. But you wouldn't know it from the way "Aggs" are reported as gospel. And many among the BR & F-class crowd are knowledgeable enough to understand this. I suspect anyone who's competed for a season in BR understands that their rifle doesn't shoot a group equivalent to it's "Agg" every single time they shoot a relay.

But it certainly sounds more impressive to report an average (and to allow the uninitiated to assume that is representative of every group printed by the rifle) than to talk about the largest 25-30% of the groups the rifle has been recorded to shoot. Or the largest 10%.


Essentially, Benchrest shooters don't seem to care about the largest groups their rifle shoots on record, and prefer to disregard large groups as "unlucky" while focusing on the average group size the rifle shoots over many small samples. Which is fine, as long as it's understood that's what is being done.

 

[Gogga]

It's the usual case of trying to take something complex and nuanced and distilling it down to a single number. Whilst it is easier to digest it can be simplistic and can mislead. Much better would be to declare the average, min and max, but unless you can remove the shooter ability noise from it all it only tells you what that rifle in those hands could do on that day.

 

[MarkyMark007]

Based on what you're saying, it seems to me that the concept of an "Agg" is designed cast a rifle (and shooter) in a positive light by focusing on an average instead of the largest group that the rifle has shot on record. Which is all well and good within the realm of benchrest competition.

But I think it's important to emphasize that the use of an average will all but erase the largest groups shot by the rifle as these are likely to be as rare as the smallest groups, and so will be drowned out as noise. The only thing more biased toward an ideal outcome would be only reporting the best groups. Heck, using an average effectively disregards the largest half of individual groups/samples shot by the rifle.

Again I could be wrong here, but there seems to be no effort made to record or report the largest group of the sample, something that would be more evident when using a single large sample, or several large samples. In fact, quite the opposite, as one can just accumulate more small samples to drown out any unfavorable data points.

This tendency to rely on averages is actually using statistics to make a rifle appear to have a higher level of ultimate precision that it might if data were recorded differently.

You give the example of a smaller group being lucky (it's not luck, just probability) and distorting a small set of samples, but being absorbed in a larger set. The opposite is also very much true. But you wouldn't know it from the way "Aggs" are reported as gospel. And many among the BR & F-class crowd are knowledgeable enough to understand this. I suspect anyone who's competed for a season in BR understands that their rifle doesn't shoot a group equivalent to it's "Agg" every single time they shoot a relay.

But it certainly sounds more impressive to report an average (and to allow the uninitiated to assume that is representative of every group printed by the rifle) than to talk about the largest 25-30% of the groups the rifle has been recorded to shoot. Or the largest 10%.


Essentially, Benchrest shooters don't seem to care about the largest groups their rifle shoots on record, and prefer to disregard large groups as "unlucky" while focusing on the average group size the rifle shoots over many small samples. Which is fine, as long as it's understood that's what is being done.

agging is of course 'avergare'. and that is perfectly fine for 5-shot groups.
because all goups (3-/5-/10-shot... follow gauss/normal distribution pattern; from very very small (very rare event) to very very large (also very very rare event):

and average is just average of all those groups. and more there are those groups, more confident we can be that this is our REAL AVERAGE 5-shot group. and the smallest and the largest groups are lucky / one time event, which happened very rare.

and if those groups are from matches, it combines the largest and the smallest ones. which is correct.

but hornady is saying that after 50 shots, group does not expand any more. so if we want translate this AVERAGE 5-shot group to hornady 'language', we must multiply 5-shot group by factor. and i am sure that in this case we must look at average group, not the smallest and not the biggest.

and by statistic AVEGARE 3-shot groups will be smaller than AVERAGE 5-shot groups, and those smaller than AVERAGE 10-shot group... till we reach 50-shot group (by hornady), which wont expand anymore.

and funny thing; if average benchrest 5-shot group is 0.25 MOA, translate to hornady 50-shot group by multipliing factor, it gives ~0.57 MOA group (if I am correct).
so statement from hornady, that they didnt see 0.5 MOA gun from their perspective, is CORRECT !

 

[MarkyMark007]

approximate multiplying factors (50-shot group / x-shot group), but I thing they should be corrected by real statistics:

Here to stir pot on seating depth

This data is from 100 rounds of what I would consider "average" factory match ammo. Not the best in the world, not the worst. I broke the 100 shots, of which I have MV, X and Y for each shot as recorded on an acoustic target and Oehler 85 optical chronograph system, into 33x 3 shot groups, 20x...

www.snipershide.com

 

[Tx_Aggie]

approximate multiplying factors (50-shot group / x-shot group), but I thing they should be corrected by real statistics:

Here to stir pot on seating depth

This data is from 100 rounds of what I would consider "average" factory match ammo. Not the best in the world, not the worst. I broke the 100 shots, of which I have MV, X and Y for each shot as recorded on an acoustic target and Oehler 85 optical chronograph system, into 33x 3 shot groups, 20x...

www.snipershide.com

That's a great link.

LedZep's posts in that thread are excellent (as is yours). It could be really eye opening for someone who hasn't thought much about statistics and how they might interact with common load development practices.

 

[timintx]

The aggregate in 1000 yd Benchrest is generally an agg of anywhere from 4-6 different groups in each class in which the rifle was cleaned between targets . This helps to keep level velocities on every target with limited shots being shot and is the reason we can hold low ES on each group and why seating depth is so important. Usually no more than 10 shots with sighters are fired on each group in light gun class . Heavy gun class are 10 shot groups which are harder to hold low ES due to more shots fired and heating of the barrel can cause spikes in velocity . At the same time they are also scored as to where they hit . So there are a few ways they are averaged. Agg for light group, ,agg for heavy group , agg for light score, agg for heavy score, and grand agg which is a combination of both rifles for both group and score.

Timintx

 

[secondofangle2]

You could remove a lot of the bias in measuring and aggregate in groups by changing the metric from group size center to center to the distance from the center of each impact to the point of aim.

If you had that metric, and I’d like to have some software that could measure it quickly, you could then take a simple average of every single shot’s distance from the point of them, and get a very statistically valid, practically useful average

 

[RegionRat]

The OnTarget software can do the target analysis and even composite more than one target to give mean radius as well as distance to aim point data…. However… the BR rules community is pretty set in their ways for both good and bad reasons. I don’t have a pony in that race, so I won’t take a side.
It isn’t the lack of target analysis software that is the issue, it is sticking to a set of rules.

 

[Barelstroker]

agging is of course 'avergare'. and that is perfectly fine for 5-shot groups.
because all goups (3-/5-/10-shot... follow gauss/normal distribution pattern; from very very small (very rare event) to very very large (also very very rare event):

and average is just average of all those groups. and more there are those groups, more confident we can be that this is our REAL AVERAGE 5-shot group. and the smallest and the largest groups are lucky / one time event, which happened very rare.

and if those groups are from matches, it combines the largest and the smallest ones. which is correct.

but hornady is saying that after 50 shots, group does not expand any more. so if we want translate this AVERAGE 5-shot group to hornady 'language', we must multiply 5-shot group by factor. and i am sure that in this case we must look at average group, not the smallest and not the biggest.

and by statistic AVEGARE 3-shot groups will be smaller than AVERAGE 5-shot groups, and those smaller than AVERAGE 10-shot group... till we reach 50-shot group (by hornady), which wont expand anymore.

and funny thing; if average benchrest 5-shot group is 0.25 MOA, translate to hornady 50-shot group by multipliing factor, it gives ~0.57 MOA group (if I am correct).
so statement from hornady, that they didnt see 0.5 MOA gun from their perspective, is CORRECT !

Grubbs has already formulated extrapolation tables based on SD's calculated from different sample numbers. This has all been done decades ago.

 

[dbooksta]

approximate multiplying factors (50-shot group / x-shot group), but I thing they should be corrected by real statistics:

Here to stir pot on seating depth

This data is from 100 rounds of what I would consider "average" factory match ammo. Not the best in the world, not the worst. I broke the 100 shots, of which I have MV, X and Y for each shot as recorded on an acoustic target and Oehler 85 optical chronograph system, into 33x 3 shot groups, 20x...

www.snipershide.com

Real math and statistics for this has all been worked out in detail on Ballistipedia, with significant improvements over what Grubbs was able to do 60 years ago.

 

[MarkyMark007]

Real math and statistics for this has all been worked out in detail on Ballistipedia, with significant improvements over what Grubbs was able to do 60 years ago.

I think that those group size per shots are wrong, because group size goes to infinity. from 80 to 100 shots it just keep growing by 0.01 increment.
but in reality it doesnt. it's other type of random system than what statistic says that it can go to infinity.
imho.

 

[secondofangle2]

“In the long run, we’re all dead.” - JMK

 

[dbooksta]

I think that those group size per shots are wrong, because group size goes to infinity. from 80 to 100 shots it just keep growing by 0.01 increment.
but in reality it doesnt. it's other type of random system than what statistic says that it can go to infinity.
imho.

Extreme Spread can only increase with group size. If you think that there is some absolute upper bound on shot dispersion then you could bound the sample distribution so that you never see an extreme spread beyond that, but even then the average spread for a given number of shots would only approach that value asymptotically as group size increases.

The bivariate normal distribution is an excellent fit to what we see on real-world targets, including on these composite groups running into the hundreds of shots.