5rd groups aren't statistically significant! Wanna bet?!!

[Ledzep]

1. This isn't all about you. Keep in mind it's also about people parroting you in their own interpretations. Who lack the nuance to understand there's a special condition to necessitate this large data sample on an unknown gun that was unspoken.

"I control what I say, not what they hear", Eric Cortina.

But ...even now, in this thread, I honestly feel like I hear the goal posts being moved in what you're saying. Here's why.

There's never been any caveat given about DOPE. Data on prior engagements. That's never been in the conversation until now. And like the other guy, ....in what world are we gathering meaningful data on the first 30 rounds in a gun?

No. Actually. We've specifically said on the podcast that what we do is to shoot 100-150 rounds to make sure everything on the gun is solid (no wonky bedding, loose rings, let the barrel speed up or do its thing whatever), let the barrel brake in, then conduct whatever load development we're going to do. At the same time, doing 20-30 shot strings for load development, guess what? When I pick the best one I already have the data! I plug it in and go. The only other time that shooting a large sample is necessary is in truing a ballistic file at long range or if something changes or goes wrong.

Of course we have previous data and history with the gun. It's our gun! Lol. And we get a certain number of rounds down the barrel before we start taking the results real seriously. So our understanding of the rifle, the load, and it's capabilities is always a constant in these discussions. So when you say broadly, without caveat, "A 30rd sample is the minimum amount to truly understand your gun", everyone assumes that's along with and on top of what they're already doing with their rifles. (Yeah, you didn't say that in your last post, but you've said it before. And so has everyone that parrots you). Here's another reason why. Despite what I just typed, you are also saying this by 30rd by giving the basic statistical truth that 30rds will give a better statistical truth than 5. I know, I agree, in a vacuum. But just that one sentence alone gets exported to people believing they need to shoot 30rd groups every time they go to the range. The basic, undeniable truth that a large sample size gives greater confidence....skips right over the consideration of what a shooter can practically use from that data set for a lot of people when they hear it.

Again, I can control what I say, not what people read/hear... Dunno what to tell you. It's a podcast. I don't have the time and nobody (well, not many) wants to listen to 7 hours of preamble on statistics 101 before I give a dissertation on 5,000 rounds worth of recorded data. It's not a great platform for disseminating hard data. We've had that conversation inside and outside of the company before. We do our best to condense it down but at the end of the day it's a free-flow conversation with some limited aides.

Look at it this way. What if on your podcast you had said, "You really need at least 30rds to understand what your gun and load are capable of, but it doesn't need to be shot in one sitting or even on the same day".

I remember myself and Jayden talking about shooting multiple sets of small groups as long as you correlate POI/POA it's the same thing. Might not have been the original "your groups are too small" podcast but one of the following ones. He shoots 7x 3 shot group for his hunting rifles because the thin barrels and magnum cartridges perform differently due to heat on a 3x vs. even a 5x or especially a 10x. Totally valid. No issue.

Mixing it up on different days only serves to make the data set more messy. If the wind changes direction or magnitude it changes POI. If the temperature changes it can affect average MV (a good test to do anyway, but better when it's more controlled if you can imagine). It's doable but less than ideal.

Then it would be a pretty unnoteworthy statement and everyone would have shrugged their shoulders and walked away. And it wouldn't have justified the click bait title of the video, "Your groups are too small". And honestly, I don't think that's even what you meant. I very much think you straight up meant to tell people that they need to lay down and shoot a 30rd group every time they want to see what their MV, SD, and group size looks like because anything smaller is a lie.

The marketing team at Hornady is tired of hearing me bitch about "marketing" and "clickbait". But guess what, they're marketing nerds and the more clicks they get the better (or so they say.. Idk.). Such is life. Engineers make poor salesmen.

And to just play the same game, I agree! A larger sample size is going to provide better data. But I still maintain that "better data" isn't always usable and the cons of shooting 30rd groups everytime you go to the range is F'ing retarded.

I feel like I've said this before (in this thread....), but I shoot 30x rounds once *Unless I change a meaningful variable (muzzle device, load, optic, barrel, etc.)*. After that I shoot steel and animals. The data from the first 30x shot string after the barrel is broken in is the same throughout the useful life of the barrel. The only thing that should change is maybe MV creep with temperature or the barrel wearing out. I build a 4DoF profile and rock and roll.

The only time you need 30x shots is to get that initial data, or to compare different loads or to zero a new scope, or if I believe something is awry etc. I don't shoot 20x every range trip. My 4DoF file is set I lay down and smack steel and will only touch 100yd if I think something is wrong. Truthfully I prefer 300yd for "close range verification". Better resolution, less parallax issues, etc.


At the end of the day, do whatever makes you happy. We get a ton of hate thrown our way for what is essentially talking about common knowledge in other fields and the entire intent is to shoot less on paper at 100yd and more at steel. You can dick around with a 100yd zero check every range trip and burn up components in a near-useless 5-shot or ladder test or OCW test or Satterlee test, or you can put the shit together, break in the barrel, find an acceptable load in short order, get solid data on it and run with it. If you interpret that as "You must shoot 30 shots every time you lay down", I can't help you. The point is to knock out the BS early, set it up and rock and roll, always has been.

 

[Ledzep]

Not technically correct that the average of the SDs will always be lower than a combined SD.

I ran a simulation study where the sample SD from 6 groups of sample size 5 were calculate, then averaged and the grand SD of all 30. There’s about 21.7% likelihood that the average of the 6 SDs would be greater than the grand SD with a 99% CI [21.3%, 22.0%].

I ran it with sample sizes as 50 and the likelihood jumped to 25.6% with a 99% CI [25.2%, 25.9%]. The main take away is that the SD distribution is highly variable compared to other distributions like the sample mean.

But, I think your general point is fair since what you claimed happens on average 74.47-78.3% of the time.

I'll look into that. I could be wrong but I do not ever remember seeing that happen with real data, nor my simulated distributions.

I did 'the maths in skool' boss, I understand sample size populations, and will never argue against the statistical importance of a larger population.

My point *outside the part you quoted* was to the relevance of the sample size of an aggregate vs large sample - as it pertains to the vast, vast majority of shooters.

Let's use your SD point... Is a ~4 FPS SD increase (30 shot result of OPs samples vs his lowest 5 shot sample) relevant to elevation adjustment at say 800 yards? We know the answer, it is about a half inch, or a little less than one-fifth of .1 mil.

Either way man, we're going around in circles partially agreeing, and partially not. There's enough animosity already here that I don't need to add to it.

No animosity on my end. It's just math and physics. It's better for me, it's better for everyone to know more. Whether or not it's worth the effort is up to the individual. If you're going to smoke a whitetail at 54yd in the same stand your family has used since 1974, this is all a waste of time.

If you're hunting mulies out west and you want to know if you have a true SD of 8fps or 12fps, well that means a possible ES of ~50fps or ~75fps and that drives the cone of fire both vertically (velocity variation) and horizontally (wind deflection variation due to MV variation). And if you're so inclined you can run simulations and find out exactly what effect that has on a kill-zone target and how that, and many other things affect your potential shots. Mental masturbation, sure. Unnecssary? Maybe??? Depends on who you are and what you're doing.

All it is, is a better understanding of what you're doing.

 

[Beefmanne]

 

[Aftermath]

There are guys here that will take 2 bites out of a shit sandwich.

 

[Holliday]

I've been around long enough to see trends come and go. Just a few years back, you were labeled as mentally handicapped if you didn't shoot a 10-shot ladder and 'look for flat spots'. Prior to that it was OCW.

Exactly.

It is amazing how the level righteousness from the latest “have you heard the good news” crowd, never diminishes.

 

[JR1200W3]

Mixing it up on different days only serves to make the data set more messy. If the wind changes direction or magnitude it changes POI. If the temperature changes it can affect average MV (a good test to do anyway, but better when it's more controlled if you can imagine). It's doable but less than ideal.

Personally, I like shooting my zero in different conditions and positions. And collecting incidental data here and there just to reaffirm confidence. Obviously, I don't put a lot of stock in shooting a shit ton of ammo at 100yd test targets to build SD, Mean, and ES libraries. But I will shoot 100yd paper from challenging positions on the clock to check, not my guns zero, but my ability to shoot a consistent POI and practice seeing my impacts on target.

IMO being able to maintain the same zero across all ranges, positions, and environments is the big dick move. I think a lot of people assume they do but they don't. They confuse shooter-zero issues with ballistic computer, profile, CDM, F'n David Tubbs DTAC BC's, mirage influence, the lighting changed, data issues. The anchor of your ballistic solution is your zero and most people only test their zero in a contrived prone, flat range, slow fire type of environment. When I can shoot my zero in varied and challenging environments on the clock, and my gun maintains a similar enough MV and the load keeps single digit SDs, the only remaining challenges are the mental game and wind. Personally, I don't sweat my data at distance. I have enough confidence and faith in Berger bullets, AB, and CDMs that I don't need to spend a lot of time checking true at distance. And you build that intuition after you shoot a match and you had no elevational misses.

When I'm actually zeroing my gun, I zero my 300yd data at 300. Your bullet will be within 0.1" inch for 10-20 yds prior to 100 and 10-20yds after 100. So when you're zero'ing at 100, you have a much smaller chance of perfectly nailing it than you do at 300. And we don't shoot 100yd targets in competitions. Perhaps this is the only thing we can both get on board with.

As far as shooting more on steel than paper, sure. I think most of us do but I also think there's a lot of unresolved misunderstandings that get made on steel. The issue with steel is people only want to shoot it once. And man, they take that high center shot as the gospel. That one round represents the exact center of their shot group. Sure. Somehow forgetting they're employing a certain cone of fire and that one hit was just in the extreme edge of their group size at that distance. And you can see it in play when they miss off the left, correct right and miss off right. Shake their head swear the wind just fucked them.

If you interpret that as "You must shoot 30 shots every time you lay down", I can't help you.

No, I don't interpret that as you must shoot 30rds groups everytime you lay down but I do interpret "Your groups are too small" as you need to shoot larger(30rd) groups. Who said that?

 

[DasherDialedIn]

wait...so how small are your groups in that 30 shot string? Show us your 1/4moa 5 shot group...that's all we care about