No Offense intended at all.... but your quoted first sentence is not my goal...."If our goal is to characterize a range statistic using the least number of shots then we should pick our group size carefully"


I actually will stay with 10 shoots, I have found 10 shoots to be beneficial to my training.

While statistically speaking... 7 shoots might be optimum mathematically.... I have rarely seen a mathematical formula translate into real world, everyday performance.

As a matter of fact, I just had a repeated  shot 7 or shot 8 issue, ( IMHO, scope related ) that I may not have been able to detect the "defect" with just 7 shots groups.

I am glad I was shooting 10 shot groups, and I feel, with an AR15, it is a better reflection of the overall accuracy of the type of rifle action, ( semi auto ) and the variables and idiosyncrasies associated within it.


I mean would that mathematical formula apply to all rifle actions ? ... Single shot ? Bolt action ? S/A , Full Auto ?... or is that formula better suited to a bench rest 28lb rifle ? .... I hope that makes sense.

Those are variables to consider as well.....maybe not statistically.... but certainly in the world of the Semi-Auto.

I truly believe there are different appropriate "shots" fired group sizes for different uses of a rifle.... for deer-sized + hunting a 3 shot group is probably the most practical... when the rifle is used as intended, you would rarely fire it more then 3 times, and it almost always will be from a cold bore....on the other end is the 28lb Bench rifle... its purpose is completely different then a LtWt Hiking rifle....... those are variables that should be considered.

So..... 10 shots is a suitable indication of what your semi-automatic action AR15 is capable of when compared to other AR15's.

10 shots will have warmed up the action / rifle / barrel enough to show what it can do.


Just my 2 cents, and I truly respect your ( Happy2Shoot ) looking into the question so thoroughly.... but I still think 10 shots is better suited to the semi-auto rifles and all the banging around parts.

You made me think about something I had never considered.... and honestly, I probably would have just skipped over the Handloader magazine article, also enlightening.

I really am not trying to argue or disprove your point....I just think 10 shoots is worthwhile.


Happy2Shoot ( for that matter, anyone ), seriously , if I am the wrong track, please tell me, and if you could explain..... Because I would like to be better educated about shooting. ( Truly no sarcasm intended )

OP, cool info and confirms my observations about shooting far-from-useless 3 shot groups.

Umm, the OP says, in the last line of text, that 3 shot groups are a waste of bullets.

Yep, umm, he's got his opinion about the info and I got mine, mine based in shooting a metric shit-ton of outgoing rifles and my outright domination of the 1MOA/SPR  board.

I'm aware of your position, Mark, believe me. Just saying that the info in the OP doesn't really support it.

And I'm looking for an opportunity to reshoot the MOA challenge now that I have my MBT (thank you for that).

90% doesn't support what ?

^^^

Thanks, I did think those were all your words.

No worries, neat stuff and thanks again for posting.

Let's welcome as much info as we can get.

Keep in mind Molon has long ago hung his hat on 10-shot groups and is constantly hellbent to justify 10-shot groups.  
Molon found it back in his heart to grace us with his presence after I shot and ate his sacred 10-round cow with 3 well placed shots.



3-round groups tell me whether a rifle is shippable enough to land a spot on the 1MOA SPR ladder.

ETA - and the OP's 90% probability chart is what I already knew.

Nobody sees more daily shooting results of brand new rifles than me.

I use 10 shot strings for one thing, and that's chrono data. If I'm testing reloads, I use 5 shot groups. Zeroing an optic, three & adjust.

There is, IMHO, a difference between what's required for laboratory-grade statistical analysis and what is "plenty damn good enough". I used to use 10 shot groups when I was testing reloads; then I found I was going through a lot of components trying to arrive at a decent load, and at some point, shooter fatigue becomes an issue. I went to 5 shot groups and you know what? My reloads shoot just fine. Good enough to make the cut on the MOA challenge.

Molon does his thing with 10 shot groups and that's great.  He's doing the next best thing to lab-condition shooting and his results are unquestionable. Mark LaRue test shoots his rifles with 3 shot groups and the MOA All Day results show that his guns also do just fine with larger groups. I hate imagine how much ammo he'd go through if he tested every upper with 10 shots.  3 works for him and that's fine.

Honestly, I really wish folks in my beloved Ammo forum would worry less about how many shots are in someone else's groups. Shoot more, worry less.

My .02.

10-shot groups shot out of a single barrel someone happened to get off a barrel line somewhere tells us what that and only that barrel will do, not whether or not a groundhog is in mortal danger from a bullet flung from a barrel other than the one in the test.

^^^

I make my barrels with a certain precision process, a process that I know produces highly likely results. I don't have to shoot my barrels to see if they'll shoot, I only shoot them to head off doubts the new owner will naturally have.

Statistical bump

Hmmm, your descibing Molon's internet postings as "internet postings" was, well, unexpected.  

^^^

Your characterization of the situation ...

Public service announcement.

Maybe I'll start shooting 0-shot groups, you know, just like the big name high end barrel makers.