Advanced Marksmanship The Measure of a Man and His Rifle

[Lowlight]

The problem is,

People want a visual test, and one that doesn't take two weeks or 20 rounds to shoot, they want to be able to demonstrate capabilities without getting lawyers and scientists involved because statistically speaking your sample size is too small, ya we get it, what changed?

Our sample size has been too small for 100+ years so why keep bringing it up like people will change it, those who want to take the time to test, rifle through all the data, build profiles in excellence using 50 shot muzzle velocities and 20 shot groups, and dedicated software to read it all is on them. It doesn't make 99.9% of them any better shooters because they refuse to acknowledge their own shortcomings so in order to ignore those pesky facts, we throw numbers at the wall

Numbers, numbers, numbers, let's repeat as many numbers as much as possible, regurgitation is an art form with some.

I need more numbers, in fact, I have too few numbers today, so let me go out and make more that have very little bearing on my actual shooting.

Then once they finally reach a point of gathering all the data they feel comfortable with, they now have enough data to realistically and in their mind, scientifically answer the question, they need a new barrel and have to start over.

It's the endless cycle of load development, crunch number, test, wash, rinse, repeat and I never have to go out and shoot in front of anyone because we just aren't quite ready to commit. I might be overlooking something important.

All people want to do is shoot a group, visually demonstrate their performance and move on. They don't need a scientific analysis of their sample size. It's enough to say at that moment I did X Inches

 

[Dthomas3523]

The problem is,

People want a visual test, and one that doesn't take two weeks or 20 rounds to shoot, they want to be able to demonstrate capabilities without getting lawyers and scientists involved because statistically speaking your sample size is too small, ya we get it, what changed?

Our sample size has been too small for 100+ years so why keep bringing it up like people will change it, those who want to take the time to test, rifle through all the data, build profiles in excellence using 50 shot muzzle velocities and 20 shot groups, and dedicated software to read it all is on them. It doesn't make 99.9% of them any better shooters because they refuse to acknowledge their own shortcomings so in order to ignore those pesky facts, we throw numbers at the wall

Numbers, numbers, numbers, let's repeat as many numbers as much as possible, regurgitation is an art form with some.

I need more numbers, in fact, I have too few numbers today, so let me go out and make more that have very little bearing on my actual shooting.

Then once they finally reach a point of gathering all the data they feel comfortable with, they now have enough data to realistically and in their mind, scientifically answer the question, they need a new barrel and have to start over.

It's the endless cycle of load development, crunch number, test, wash, rinse, repeat and I never have to go out and shoot in front of anyone because we just aren't quite ready to commit. I might be overlooking something important.

All people want to do is shoot a group, visually demonstrate their performance and move on. They don't need a scientific analysis of their sample size. It's enough to say at that moment I did X Inches

This. ^^^^ Stop telling people all their stuff doesn’t matter. Maybe it doesn’t, but you’re not going to change them.

So, give them something simple. And the guys who know better or want to accumulate data will keep the targets we shoot over time and compile data.

All constantly telling people this is just

A: telling smarter/interested people what they already know or can figure out on their own

B: discouraging ones that don’t care or don’t have the ability to sort all that out

At best you’re telling people what they already know and at worst discouraging people.

 

[Rocketvapor]

For some it's NEVER enough. This new powder, this new bullet, is it better?
For some it's MOA with a Gasser. For me it's "I am not done" next time it's going to be better, then the next, add some nausium.

 

[Lowlight]

I honestly believe with some people, all that hunting for data is looking for a reason to say it's not them.

Wasn't me, I tested my load over 50 shots at 200 yards and it proved through my scientific method that my variation from shot to shot being 3.267473fps different from the previous 3 shots of 3.5626305fps states I can have a random fluctuation in group size of 1.23% every 100 yards, of which I am only shooting 1 right now, but it can and will matter if I attempt to shoot farther so I better not.

Ya, I would have hit that shot, but my error budget as stated in the Applied Ballistics WEZ for my load at that given distance is prone to a dispersion rate of 2.87% in a westerly prevailing wind that I completely ignored because I was thinking about everything else. So this data demonstrates to all, it wasn't me. The 57 shots taken over my Labrabar with an SD of 2, and ES of 57 is really the culprit, sure I printed a tiny group at 100, but that variation in SD means I could throw one if I am not careful.

Dont forget to drop a lot of names, like Bryan Litz, Applied Ballistics, Kenny the guy from South Park, along with a lot of extra decimal places.

 

[Lowlight]

I get it now,

Everyone read the Statistics Post on the PRB and that is why we are talking sample size this week, the world is a little bit smarter so they want to use that new-found knowledge to blow up some norms

 

[Lowlight]

Twenty rounds is pretty good, about 90%, and at fifty rounds you get to some 98%. If we intend to evaluate the whole system, I'd prefer to shoot several five shot groups over time, then overlay the results to get a true measure of performance.

@CoryT I think you have the key element here, overlaying groups over time vs doing the 20+ shots all at once which is sort of the point we have been making, shooter.

Wouldn't you say for a new shooter or a less than experienced shooter trying to put together 1 -20 shot group in a single sitting to be a difficult endeavour vs overlaying a series of smaller groups?

To me this sort of lends to the effort, the risk vs reward, if every time a shooter tried to put together a 20 shot group they screw it up, they are more likely to give up. Overlaying smaller samples, like 1 shot per target, makes it easier on the brain.

Most people can put together a pretty representative 5 shot group vs 20, which requires a ton of effort to string together in a single sitting. That I can get behind... sort of like the cold bore targets that one would use each trip. Accumulate data but not all at once.

 

[roostercogburn98]

Wouldn’t shooting multiple strings over time and overlapping also give a chance for the elements to come into play? If it is all about evaluating the whole system, then different light and weather conditions would change how a person shoots as well right?
I’m no pro shooter, but sitting in the deer blind watching it rain and reading this made me wonder.

 

[Lowlight]

So the progressive dot drill

 

[Deleted member 113831]

It all depends on what you are trying to do with the data. A single 3 shot group is only what it is, you can't tell much of anything from 3 shots, except to say it does not appear to be accurate or precise. Even a single 5 shot group does not have any real value to predicting what the next group will be. Measuring group size by the typical extreme spread also has little real world value. It's easy and simple, but any ES measurement consists of exactly two data points. Two data points is a very small sample that has almost no value. what you will find is that as the population of events from which you draw the two points from gets larger, so will the ES. Welcome to a standard distribution bell curve.

If you want to evaluate precision and accuracy, you really want to use mean radius or circular error probable. These are much harder to measure, though there are software programs that will do the hard work. In order to get a value that has real meaning, that is, we can use it to predict future performance with some reasonable degree of success, you'll need twenty to fifty rounds to measure. As you increase the data set, the confidence level goes up. Twenty rounds is pretty good, about 90%, and at fifty rounds you get to some 98%. If we intend to evaluate the whole system, I'd prefer to shoot several five shot groups over time, then overlay the results to get a true measure of performance.

Humans are a huge variable component in the system. One five shot group can't even tell us if the rifle is zeroed.

The twenty single shots is a very good test, especially if those shots are fired over a course of several days. When I went up to the Smithy every day, I would go out back and shoot two shots from my test rifle each day, one in the AM and one before leaving in the PM. After two weeks, you have twenty shots that give you a VERY good indication of the actual group size, group center and average distance to the POA. This is not what I'd call convenient for most shooters to do, but it does produce very useful data. We are now testing the ability of the shooter and system to repeatedly acquire a position and engage a target. If you want to do consecutive shots, so as to make a five shot group, it would be wise to break the position and start fresh on the next shot.

@CoryT I think you have the key element here, overlaying groups over time vs doing the 20+ shots all at once which is sort of the point we have been making, shooter.

Wouldn't you say for a new shooter or a less than experienced shooter trying to put together 1 -20 shot group in a single sitting to be a difficult endeavour vs overlaying a series of smaller groups?

To me this sort of lends to the effort, the risk vs reward, if every time a shooter tried to put together a 20 shot group they screw it up, they are more likely to give up. Overlaying smaller samples, like 1 shot per target, makes it easier on the brain.

Most people can put together a pretty representative 5 shot group vs 20, which requires a ton of effort to string together in a single sitting. That I can get behind... sort of like the cold bore targets that one would use each trip. Accumulate data but not all at once.

So, now we have gone all the way around the mullberry bush and have come back to 20 shots (in whatever manner you deem most appropriate).

Next you'll be shooting at 200 yards.

 

[Lowlight]

So, now we have gone all the way around the mullberry bush and have come back to 20 shots (in whatever manner you deem most appropriate).

Next you'll be shooting at 200 yards.

not really just making it option

Nothing I am doing is focused on 200

recognizing the positives of doing something is very different from people actually doing it

The idea is to hit on something better that people will actually execute vs just talking about it

If you can give them a target that can be shot over time, each week, etc, I have no issue with that, the point is, it's unfair to think people will put together a 20 shot group vs a 5 shot one. That said you might convince people to do 5 at a time and just overlay it over the course of 5 range trips.

Nobody will do what you are suggesting, nor will they do a lot of what is suggested, the idea is to find something they will do that will open the door to something better.

 

[Deleted member 113831]

not really just making it option

Nothing I am doing is focused on 200

recognizing the positives of doing something is very different from people actually doing it

The idea is to hit on something better that people will actually execute vs just talking about it

If you can give them a target that can be shot over time, each week, etc, I have no issue with that, the point is, it's unfair to think people will put together a 20 shot vs a 5 shot one. That said you might convince people to do 5 at a time and just overlay it over the course of 5 range trips.

Nobody will do what you are suggesting, nor will they do a lot of what is suggested, the idea is to find something they will do that will open the door to something better.

Just a little friendly jab. I think you're right about people not wanting to do most of this. People post shit for bragging rights. This would likely impede thier positive feedback loop.

I shot two 20 round groups (more accurately 4 groups of 5rnds at same point of aim) this morning at 200 yards to try and diagnose a shitty barrel. Had I shot 5rnd groups at 100 yards, I likely would have walked away happier.

After 2 chambers in 300Win, and 1 chamber in 30-06 and about 400 bullets down range in similar tests trying to get it to shoot... I proved to myself that this barrel is a 2moa piece of shit and is going back to it's maker.

 

[Lowlight]

Ya, I am just trying to be realistic and ease people into doing something better, vs having to debate what a 5 shot group means.

I get there are best practices out there for this, and volume, data, the stats, all come into play. But the reality is, we are limited by what people will do. We turn away quickly if discouraged.

These same conversations come around every few years, the fact PRB came out with an article and it started up again makes sense. Guys start saying your sample size is meaningless and people suddenly want 20 rounds shot vs 5, and you go, okay what changed again. New Article, got it. But we have to operate inside the box, we can cut holes and hope people see a better way outside, but you can't force them.

You have to be practical when trying to lead people in a certain direction.

 

[TxWelder35]

I honestly believe with some people, all that hunting for data is looking for a reason to say it's not them.

Wasn't me, I tested my load over 50 shots at 200 yards and it proved through my scientific method that my variation from shot to shot being 3.267473fps different from the previous 3 shots of 3.5626305fps states I can have a random fluctuation in group size of 1.23% every 100 yards, of which I am only shooting 1 right now, but it can and will matter if I attempt to shoot farther so I better not.

Ya, I would have hit that shot, but my error budget as stated in the Applied Ballistics WEZ for my load at that given distance is prone to a dispersion rate of 2.87% in a westerly prevailing wind that I completely ignored because I was thinking about everything else. So this data demonstrates to all, it wasn't me. The 57 shots taken over my Labrabar with an SD of 2, and ES of 57 is really the culprit, sure I printed a tiny group at 100, but that variation in SD means I could throw one if I am not careful.

Dont forget to drop a lot of names, like Bryan Litz, Applied Ballistics, Kenny the guy from South Park, along with a lot of extra decimal places.

Shot with a guy like that this past weekend. Every excuse in the book why he couldn’t hit 1000 yard target oh my load this, oh my load that, oh I didn’t realize this 8 twist on a 300wm trying to shoot 245s was bad idea.

new barrel on my 260, picked a load I figured would do well. No development. 42gr of 4350, Berger 140 .030 off jam, and loaded them up. Hits at a mile, 7/7 at 1300 In a 7-8” group.

I guess some people just enjoy burning out a barrel chasing the perfect load then doing it all over again.

 

[CoryT]

I think a single twenty round string is not optimum for most shooters. I think if you do the twenty round target I’d take a break every five rounds. If you just keep every five round group you fire over several range session then combine them you’d get a pretty good idea how things are working. That lets you go to the range and do more that just shoot 100y groups. In class, each day you are on the 100y range, get in one group, or one line on the multi dot target.

 

[MadDuner]

My equipment is far better than I am, but I will also be limited to using factory ammo at the moment.
I’m looking forward to trying the dot groups at different distances to see where I end up.
Thanks to everyone for the info.

 

[GrumpyOleFart]

I can see this being a radical Reality Check for a lot of people.
Excellent!
Happy New Year!

 

[Moe Ron]

Do we judge golfers, bowlers, musicians whatever by their performance at one event?
Shouldn’t the judge of a good marksman and his/her equipment be consistency over an extended period of time? Months, years? Could be I’m missing the goal here.

 

[MadDuner]

Do we judge golfers, bowlers, musicians whatever by their performance at one event?
Shouldn’t the judge of a good marksman and his/her equipment be consistency over an extended period of time? Months, years? Could be I’m missing the goal here.

Lucky for us - the internet allows us to not post up the pics of our targets on the days we can’t shoot for beans.... We get to post only our best days efforts and pretend it always looks like that!

 

[Moe Ron]

I know absolutely nuttn’ bout match shooting
I’ve been in golf leagues where you kept track of scores and had a “handicap”. The lower your average score the lower you handicap.
All that explanation for non golfers

Aren’t the top pro shooters out there the standard?

 

[Near miss]

Wait a minute I do not think anybody has said that a single 20 round group would be needed. It makes no sense.
Just 20 shots. It is only about the amount of data points, I shoot 5 round groups and collate them to bigger ones. 5 to 10 rounds and it gets hard to locate all shots on paper.

@CoryT I once checked my rimfire scores to see the price of round against accuracy and ES and mean radius were quite well linked. However, this was using collated groups. Not some 5 shot groups but 15 to 40 shots.

 

[LSa]

I use mrad reticle with mrad clicks. And also play in metric environment (range, target size, wind and target speed…).

I usually zero using 100-meter range, but I zero my scope using point blank range elevation. So, my reticle middle point is somewhere between 160-190 meters, depending of the gun and ammo. And I also zero PBR if I got to zero somewhere else, like in 123 meters out of the field, or in a 300 m range. I prefer zero using PBR to get all help I can get to my field work, so instead of using 100 m middle cross I put bullets path ahead of everything.

MOA is a good accuracy standard, but because my environment is metric, my accuracy standard is not MOA. It’s a little bit bigger than MOA - I use 0,3 mrad. If my shooting is not that with prone, I need to improve my fundamentals, and if every shot stays inside 0,3 mrad, I’m using too easy positions and/or shooting too slow. My rifle, optic, ammo, support -combination can shoot better than me. I don’t play with extreme long ranges, so extreme accuracy is not needed. And if someone got a better rifle, or are better shooter, I’m very happy with him/her. I train sniping, so decent accuracy is enough for me, and in my case the weakest link is behind the rifle.

I shoot usually 4 round groups. With 3, I don’t know if one hole is on the wrong side of the group, and if I compare to 5 round groups – with 4, I can have one group more, when I got a 20 round box of ammo. I shoot groups to training fundamentals or to test ammo.

I made this target with PowerPoint, size was A3 for printing. Landscape orientation gives more room for wind errors. Center cross is for zeroing and upper crosses are for confirmation. Optics reticle is vertical and horizontal, so usually I just draw big x to cardboard to get good visual point of aim, if I need tight group. So I used crosses also here.

If you want to play with spotter, you can find lot of options here. With crosses, you can also use crosses extremities, like “blue, lower left”. Gray and green are also dot and square -shaped. Or you can command to shoot between black and green. Or if the range is short and you are shooting prone, you can try to touch only crosses 1 cm wide shape. Plus because this is sniper stuff, peeking face is a relevant practice target.

If range is short enough, and visibility and optics allow, I observe and measure my hits with optics. This target got centimeter scale, so if I go to check it, or take picture of it, I can see scale without measuring.

 

[1moaoff]

I'll throw a dart at this...
I agree with alot of this...

5x5 prone to validate claims of possible accuracy at 100 same day different day doesnt matter

5x5 prone at 100 moving rifle and 100% breaking position each shot. Tests shooter basic fundamentals corresponding to the base 5x5 same day different day doesnt matter

Optional 5x5 positional adds a third layer data

I'm all for 200 and dots also. For many people 100 is what they have acces to and may receive better because is more familiar though.

A fun thought would be to require posting for certain claims or instant flagging of account and flaming... JUST kidding! Kind of.

 

[1moaoff]

Hmm could this be the segregator for classification for the new series that hasn't been developed yet. Has to be shot at each match and we see a trend over time?

 

[BikePilot]

Most of this is over my head, but interesting. I really enjoyed the various drills we did on steel in your class (I was in the last Colorado class of the year I think--it was super windy). I especially liked the work where we would very the distance and of course the KYLs.

One curious observation for me is that I seemed much better on steel at distance than on the paper zero. I was probably 1 moa at best for the zero, but pretty consistently hit the 4" steel at 800yrds. That's 100% shooter but maybe somehow relevant . I was shooting an AI AX in 6.5cm. I presume it's way more accurate than I am and am not really all that concerned about testing it to the limit of it's accuracy. I'm by far the bigger variable in this situation!

 

[_Raining]

There is no reason to worry about the statistics and probability terminology and formulas etc. It is too hard to get everyone on board with confidence intervals and valid sample sizes etc. Just look at it this way: "Would I be comfortable using the result of this test/drill to choose between shooter A and shooter B to be on my team?". If the answer is no, then the test/drill probably doesn't hold significant merit. This turns all the math and shit into something instinctual we can all relate to. I would bet the answer to this question with regards to a 3 or 5 shot group would be "no".

The test/drill kind of needs to be at 100 yards or you exclude tons of people who don't have access to longer distance ranges.

1 shot at 25 different targets of varying sizes seems like a good balance between enough data to not be mostly luck based and not going insane with sample size. If people can't do 25 shots per range trip then they can split it up over multiple trips and people who shoot 100+ rounds per trip can just show multiple attempts at the drill.

 

[Leftie]

I am updating the Dot Drill target now a bit, playing around with it

View attachment 7516247

Here is the progressive one I am working on, from a 20 or 21 dot drill to 25 dots so you have your 5 x 5

This is cool - are there any particular measurements for the dots? Playing with the concept from your following post a little further, The each column in the 5 x 5 could also be used to represent different positions, with each column being shot as a progressively smaller target from the designated position?

 

[padom]

My opinion, it depends what youre trying to gauge. You? Rifle? Ammo? All 3 combined?? Consistency?

Like Frank, I can generally get behind a rifle and know pretty quickly if its a shooter or not. But if I want assurance from a new rifle/ammo combo that its going to be consistently accurate I shoot a 5x5 @ 100yds. 3 shots, just isnt enough data. 5 shots I think tells you how the rifle is going to perform but isnt the best sample to properly judge an entire system (shooter, rifle and ammo) for consistency.. Just my $0.02...

But I also could care less what people think about how my rifles shoot or how I shoot them. All I know is when I dial a target at distance and hit what Im aiming at, thats all that matters in the end when it comes to accuracy....

 

[Lowlight]

Dots are 1" down to 1/4"

One round per dot, how you do that is up to you

 

[phlegethon]

I am updating the Dot Drill target now a bit, playing around with it

View attachment 7516247

Here is the progressive one I am working on, from a 20 or 21 dot drill to 25 dots so you have your 5 x 5

I like that, you have a PDF?

 

[Lowlight]

Here is the PDF

 

[pmclaine]

I am updating the Dot Drill target now a bit, playing around with it

View attachment 7516247

Here is the progressive one I am working on, from a 20 or 21 dot drill to 25 dots so you have your 5 x 5

In this case my "cheap" would prefer 4x5 so I wouldnt have to open a second box of ammo......

Ill do that on my own individual account and leave 5x5 to the "Non Poors".

 

[pmclaine]

Here is the PDF

Great something to do Sunday.

 

[taliv]

Frank, I like the progressively smaller dots. a bit of feedback I have noticed from doing lots of dot drills: the smaller the dot, the smaller my group. aim small miss small and all that. your large dots on top row have a small dot inside, which would be useful for aiming, but some of the larger dots in the middle rows don't. If you're using that as a teaching tool and expect to see groups open up in the middle rows and then explain why, great. but if the goal is to help people make holes they can be proud of, then adding some 1/4" dots consistently across all rows would help. alternately, a size that aligns with some reticles that have a 'center gap'.

That said, I'd prefer a roughly 1" X instead of dots as it is something my eye can align easily with normal crosshairs. but dots work too.

also, the target should incorporate features that enable your group measuring app. like the boxes in the corners of a QR code that help your phone camera figure out how big and orientation, etc. put the ruler in the image so your app automatically knows how big all the dots are, and automatically identifies POA for each dot for purpose of calculating distance between the POA and POI of each dot, and aggregating them automaticaly into a group size.

also, also consider the target should also include blanks for recording environmentals, so that everyone records them the same. temp or DA, lighting conditions and direction of sun, whether shot from rest, bench, prone or with bags, etc. bullet, cartridge, velocity.

 

[pmclaine]

My concern is with my reticles at 100 yards I may not see the 1/4 inch dots.

Well thats on me and my shitty reticle choices.

In the vertical I can bisect the dots above and for horizontal I may make a reference bar or just bisect the dots to the right transitioning to dots to the left as necessary.

 

[Lowlight]

Zero .1 left of center and hold right edge

 

[Lowlight]

Dot drills are not for grouping just a single round, so focusing on a single point is pretty limiting.

Sure there is a reason some have centers and others don't quartering a target vs just dropping the floating dot on it

You are shooting 1 round, the target is really secondary, but I give you a variety so you can see. You don't always get to pick your target so having some that differ from others helps give you a variety

Fuck the atmospheric data, if that is important add it

People want to control every aspect of this, try mixing it up

I'm not changing it, you can make your own

 

[grinnergetter]

Welp, couldn't wait so I printed Frank's target legal size and had a go. My range is 100, prone, didn't hurry just sent them when comfortable. My breathing capacity/neck starting to ache really showed on the smaller dots. I need to try raising the rifle to get myself in a bit more upright position.

Skipped line 3 cause the above was too easy.
Made .2 correction on shot #4 / 4th line
Clearly fell apart on the smallest dots.

DT SAC 223 conversion/ factory Hornady

 

[grinnergetter]

I'd add that the top row was difficult to see the orange in the center. Perhaps white might be a better choice? Maybe that's the reason for it.

TT/ older eyes and cloudy so might not be anything significant for most shooters.

Looking at it now , I fell apart on the 4th row and thought I could compensate by making the adjustment.....poop, should not have done that.

 

[Lowlight]

You need to dial out your spin drift, cause all those right side impacts have to be spin

The top row is a black circle can you not "Quarter" the target ?

This actually points to a lot of problems just in what you are saying

 

[E-Tool]

I think these are arguments that can’t be resolved.

It’s like .45 vs 9mm or 1911 vs glock it goes on and on. The military has a simple
marksmanship qualification standard, but if you look at best sniper and similar competitions there is a strong physical component to weed out many good shooters.

Could there not be a very capable wheel chair bound shooter that’s incapable of conducting an obstacle course before their shots? What is the point?

I judge my capabilities based on hunting; with distance, movement speed, wind, and judgment calls. I aim for a clean kill or clean miss, I don’t like chasing wounded animals for any distance.

 

[dzander]

You need to dial out your spin drift, cause all those right side impacts have to be spin

Hey can you elaborate on what you mean "it has to be spin?

 

[Lowlight]

I was making a joke

 

[E-Tool]

I’m too dumb to get it lol

 

[Darkside-Six]

Where’s a can of Spin-D when you need it?

 

[Northman623]

I was making a joke

I actually snorted .

 

[grinnergetter]

Etool, dont worry too much about that. Lol. Your not alone. I admit when i read that.... WTH?

 

[dzander]

Etool, dont worry too much about that. Lol. Your not alone. I admit when i read that.... WTH?

Must be the normal competitors response when they miss huh.
I admit y’a got me

 

[LastShot300]

It all depends on what you are trying to do with the data. A single 3 shot group is only what it is, you can't tell much of anything from 3 shots, except to say it does not appear to be accurate or precise. Even a single 5 shot group does not have any real value to predicting what the next group will be. Measuring group size by the typical extreme spread also has little real world value. It's easy and simple, but any ES measurement consists of exactly two data points. Two data points is a very small sample that has almost no value. what you will find is that as the population of events from which you draw the two points from gets larger, so will the ES. Welcome to a standard distribution bell curve.

If you want to evaluate precision and accuracy, you really want to use mean radius or circular error probable. These are much harder to measure, though there are software programs that will do the hard work. In order to get a value that has real meaning, that is, we can use it to predict future performance with some reasonable degree of success, you'll need twenty to fifty rounds to measure. As you increase the data set, the confidence level goes up. Twenty rounds is pretty good, about 90%, and at fifty rounds you get to some 98%. If we intend to evaluate the whole system, I'd prefer to shoot several five shot groups over time, then overlay the results to get a true measure of performance.

Humans are a huge variable component in the system. One five shot group can't even tell us if the rifle is zeroed.

The twenty single shots is a very good test, especially if those shots are fired over a course of several days. When I went up to the Smithy every day, I would go out back and shoot two shots from my test rifle each day, one in the AM and one before leaving in the PM. After two weeks, you have twenty shots that give you a VERY good indication of the actual group size, group center and average distance to the POA. This is not what I'd call convenient for most shooters to do, but it does produce very useful data. We are now testing the ability of the shooter and system to repeatedly acquire a position and engage a target. If you want to do consecutive shots, so as to make a five shot group, it would be wise to break the position and start fresh on the next shot.

+1

 

[ma smith]

Just one more comment --re: data parttion and data sample.

5x1=5
5x5=25

In this context, talk of 1x5 or 5x1 shot group is a partition,
its not necessarily meant to indicate its "the sample"
the sample is the larger context of evaluation, eg...the 5x5=25

There are very good reasons for partitioning data,
eg Olympic biatholon you shoot 4x of 5x1
...each stage is a parition (or a "set")

But to determine the winner you,
don't shoot/eval just a single set
You do ... 5x4 sets (or whatever)

We can see that 5x5, 4x5 or 3x3 etc is a parititioned sample.

partitioning is normally done for manageability, performance or availability reasons, or for load balancing

These are worth thinking about IMHO

 

[Rocketvapor]

I want to hear more about this Spin Drift @ 100 yds.
Sounds like an excuse I could use