Your Groups Are Too Small

[Sandstrom]

 

[stan_wa]

Post 401 has pictures from the book with an example, and the note of how it is being modeled. Here it is again-

View attachment 660558


Here is a link to read the overview-

https://appliedballisticsllc.com/wp-content/uploads/2021/06/ABDOC115_ProbabalisticWEZ-2021-Copyright.pdf

I am not a mathematician, statistician, etc., regardless of how it is figured, it is used as I have done so here, and the the average level/ability of people and the hit rates that results are consistent in live fire.

I always feel like it’s hard to discuss without sounding argumentative or trying to prove my side and that’s not my hope. you seem like a guy who is all about the data which I super respect .
“95% of the estimates being within +/- 1.0 meters (+/- 2σ)”
2σ Is the symbol for 2 standard deviation.

So for the Wez input the instructions state to input standard deviation aka σ.
So if you’re saying, you can call the within x make sure to put into x\2 for standard deviation.

“ In other words, if the uncertainty in range is cited as +/- 1 meter, it means the standard deviation of range error is 0.5”

 

[Formidilosus]

I always feel like it’s hard to discuss without sounding argumentative or trying to prove my side and that’s not my hope. you seem like a guy who is all about the data which I super respect .

It’s all good man. I am not an engineer, I am a user and I know how it is supposed to be used.

“95% of the estimates being within +/- 1.0 meters (+/- 2σ)”
2σ Is the symbol for 2 standard deviation.

So for the Wez input the instructions state to input standard deviation aka σ.
So if you’re saying, you can call the within x make sure to put into x\2 for standard deviation.

“ In other words, if the uncertainty in range is cited as +/- 1 meter, it means the standard deviation of range error is 0.5”

What are you trying to say here? Are you just correcting a misunderstanding I have of the math/modeling? Or are you trying to say that an average shooter who can call wind within 4mph per the WEZ, should instead be putting in 2 mph in the WEZ?

 

[stan_wa]

I am “trying to say that an average shooter who can call wind within 4mph per the WEZ, should instead be putting in 2 mph in the WEZ?”
Exactly
Because the input is standard deviation not extreme spread, and litz assumes 2 standard deviation = extreme spread

 

[Formidilosus]

I am “trying to say that an average shooter who can call wind within 4mph per the WEZ, should instead be putting in 2 mph in the WEZ?”
Exactly
Because the input is standard deviation not extreme spread, and litz assumes 2 standard deviation = extreme spread

Negative. It is modeled/designed the way I am showing it.

 

[Macht]

@stan_wa is correct. WEZ wants the SD as input and Bryan shortcuts total uncertainty to be +/-2 SD.

 

[Shortschaf]

I am an engineer. I have never used WEZ. Based on the screenshot of the program in post #419, this agrees exactly with @stan_wa is saying

Having said that.. determining your actual wind-call SD/ES is hardly a science. Its based on lots of practice.

So if the program works for your inputs, then this is only a change in naming convention.

 

[ddowning]

Because +/- 2mph wing calling in broken , mountainous terrain is about world class level. Legit shooters practicing regularly are capable of around +/- 4mph. Furthermore, the precision levels are not attainable in the field- you are not shooting 30 round groups of .5 MOA in the field hunting.

I agree 1000%. A lot of the best prs shooters I know can barely lay down in warm weather with a bipod and rear bag and shoot multiple 10 shot groups that are <1/2moa. This changes with other shooting positions. With a prs rifle I would say 3/4 moa from all positions is pretty damn good/basically unheard of and 1 moa is probably only the top 10-15% of shooters at a national level match. This is also at 100 yards with minimal wind effects. Add distance and wind and the number of people who have shot a clean match for even 1 entire day is in the single digits or possibly low double digits. This is on 1.5-2.5 moa targets.

Also agree that 2mph in the mountains is world class wind calling. I'm in the midwest (no mountains) and generally place higher in matches when wind is high and variable. I am barely confident that my wind call is +/- 2mph in most conditions. Crank the wind to 15+ mph and that gets worse. Make it a fishtailing head or tailwind and most, except for the best wind callers in the world, are completely screwed.

The range at my house is across a draw. Without pulling out a topo map, I'm going to guess a 60' elevation change from top to bottom (not shit). It is common to have criss-crossing mirage. Hitting an 8" plate at 446 yards in that condition is very difficult. Sometimes, a 20 mph wind needs a 20 mph hold. Sometimes it's straight up. During winter, when there is not much vegetation between me and the target, the wind call is an educated guess.

With all the mirage going the same direction, a hit at that same 8" plate is damn near a guarantee. Conditions make a huge difference.

Also, something to keep in mind, I normally shoot cheap one day matches and place 5th or higher. There are 30 to 60 shooters behind that. All of them shoot 10x as much than the average hunter, in conditions that are closer to field conditions than the average range session. Trade my 18# match rifle for a heavy ass 13# hunting rifle and it gets that much harder to shoot. Add a heavy recoiling cartridge and it will magnify errors even more.

Form's numbers are spot-on or optimistic in my opinion.

 

[solarshooter]

I am “trying to say that an average shooter who can call wind within 4mph per the WEZ, should instead be putting in 2 mph in the WEZ?”
Exactly
Because the input is standard deviation not extreme spread, and litz assumes 2 standard deviation = extreme spread

I agree, I think it should be an SD of 2mph to capture a wind call within 4mph 95% of the time. 4mph SD would correspond to an 8mph error, aka calling 2mph or 18mph when it's 10mph... I don't think even I'm that bad! Now in mixed terrain with different wind directions and speeds along the flight of the bullet, the EFFECT might be that large, even if the call at the shooter's position is closer.

 

[solarshooter]

Bet you $100 that if you shot a 30 round group of at 54.5, 55.0, 55.5gr- there is functional difference, and almost certainly they will be within statistical variability- you have “engineered” yourself into believing that you can control small variables to effect a real outcome.

I'm assuming you meant NO functional difference. True. I guess I would need to do that to prove that the selection method is valid or not. Like I said earlier, I have already proven this for a different powder combo, but it's not certain for this powder. I could pick the worst charge from the initial ladder and shoot 20-30 to see if it remains worse than 55.5. Disprove the null hypothesis as it were. I will try and do this in the next week or two and report back. But I will be asking for that 100$ if I'm right...

I realized I have data for exactly this scenario, just on a different gun. But, *drumroll* it proves you (and many others on this thread) right!

My dad has a benchrest gun, 13lbs, Benchmark 24" M24 chambered in 6BR, Pierce single shot action, Nightforce 12-42x56 benchrest scope. I borrowed it from him to see if I could improve his load. His best load that he has shot in it for years is Lapua brass, CCI BR4s, 29.5gr Varget, Sierra 107 Matchking jumping 0.010". When I picked the gun up he also gave me 25rds of his ammo. I started by shooting all this ammo to establish a baseline for precision. Results were a 5x5 agg of 0.46" at 100yds, mean radius 0.21", SD radius 0.12".

I loaded a powder sweep, 3 shots each from 29.2 to 30.4 in 0.3gr increments, which included his original powder charge. Group sizes were as follows:

29.2, 0.32"
29.5, 0.26"
29.8, 0.26"
30.1, 0.16"
30.4, 0.30"

I of course picked 30.1 as the new "node" of interest, since I could see a "pattern" of larger then smaller groups, and it was significantly better (~60%) than the loads on either side. So then to apply the same level of rigor to it as my Dad's load, I loaded up 25 and shot 5x5. Average group was 0.50, mean radius 0.21", SD radius 0.12". Literally IDENTICAL performance to his load which was 0.6gr less powder.

So, I hereby declare that I AGREE that small changes in powder are not likely to produce significant changes in precision. And that any sort of small sample sweep of powder is a waste of time. Picking a good combo of high quality components, finding pressure, backing off to a safe level and then immediately subjecting it to larger sample size testing is a more efficient and meaningful way to do load dev. If the result isn't what you want, change components and start over.

I am actually very happy to realize this, since it makes my life easier for future load efforts. And I apologize for making people have this discussion yet again, but hopefully next time you encounter someone who believes in sweeping powder, you can just link them to this thread!

And @Formidilosus I think I owe you 100$. PM me your preferred payment method, or maybe I can buy you a cleaning rod and some patches for your poor guns .

 

[Formidilosus]

@solarshooter and @stan_wa

I found the issue that lead to confusion. My quote at the beginning-

600 yards, 12” square, wind +/- 4mph (I.E., you can call it within 4 mph 95% of the time)

The mistake is that if someone on average is a 4 mph wind caller (mean) than the program is calculating out to 2 SD to account for 95% probability. It is not that 95% of calls are within 4 mph. Apologies.

Does this make sense now?

 

[Formidilosus]

I am actually very happy to realize this, since it makes my life easier for future load efforts. And I apologize for making people have this discussion yet again, but hopefully next time you encounter someone who believes in sweeping powder, you can just link them to this thread!

Thats great that you did that, and no apologies. This has been the type of conversations/discussions that I am looking for. I wrote something incorrect and got corrected- thank you; and we got more data from someone willing to experiment- thank you.

 

[solarshooter]

@solarshooter and @stan_wa

I found the issue that lead to confusion. My quote at the beginning-




The mistake is that if someone on average is a 4 mph wind caller (mean) than the program is calculating out to 2 SD to account for 95% probability.

Does this make sense now?

Yes, when you phrase it that way I think it's consistent with the results you showed. Now I actually don't know how good of a wind caller I am with any sort of quantifiable or statistical basis, though I do have a weather station at my house and I like to go outside and try and call the wind and then check if I'm right. I'd say on average I'm within 2-3mph. But again I don't have solid data on this, and this doesn't include any effort to account for terrain effects. Maybe I should start tracking it... then I can put together the quantifiable mean and SD of my wind error! I just can't help myself haha.

Jokes aside, do you have any drills or methods to practice wind calling, other than shooting at long range in the mountains? Maybe this is a subject for a different thread...

 

[HighUintas]

Jokes aside, do you have any drills or methods to practice wind calling, other than shooting at long range in the mountains? Maybe this is a subject for a different thread...

I would also like to know. I've heard of people carrying a kestrel around to measure wind and observe what's going on to get better at it but that only works for the person's location and not the middle of a canyon 5' above your line of sight.

I unfortunately can't shoot in the mountains as often as I'd like to.

 

[Formidilosus]

Jokes aside, do you have any drills or methods to practice wind calling, other than shooting at long range in the mountains? Maybe this is a subject for a different thread...

I would also like to know. I've heard of people carrying a kestrel around to measure wind and observe what's going on to get better at it but that only works for the person's location and not the middle of a canyon 5' above your line of sight.

I unfortunately can't shoot in the mountains as often as I'd like to.

Give me a bit and I will answer.

 

[stan_wa]

--@Formidilosus i think were on the same page now. the good news according the the WEZ or hit rates will be quite a bit better for a given wind calling ability. so there is still some hope of us average guys calling wind +/-4 and having reasonable hit rates 600 yard. I would feel much better about 90-95% shots @ 600 with calling wing with in 4 mph as it seems like something a " normal" guy can learn, +/-2 seems really too hard.

So a interesting follow on question is if in your experience the hit rates are much lower (50-60)% for similar conditon to what you put in the WEZ what source or error other than wind is giving us problems? my guess based on pervious discussion, are we are less accurate in field supports, scopes lose or move zero, and our zeros aren't that good.

it seems to me that to get a reliable WEZ prediction. we would need to get the rifle precision based on the exact same shooting position we are using in the field, and we would need some way to capture the "aiming error".

 

[ddowning]

I'm extremely interested to see what Form has to say on getting wind calling experience. I'm above average, but I am not elite. Crossing winds and up and down drafts that are strong enough to move bullets wreck me. Personally, I have 3 ways, but most aren't in mountains unless you live in the mountains.

1) Every time I go to the range, I shoot at a 1.5 moa or smaller target at distance on the first shot. I try to make a first round hit and if I miss, I try to follow up with a second round hit as quickly as possible. This could be your home range, or sight in day at a match.
2)Shoot PRS/NRL type matches. Matches that have you shoot 360 degrees or have you walk a long ways will give you the most different scenarios. Obviously, if you want to call wind in mountains, shooting matches in mountains is most beneficial. Up/down drafts (thermals) still wreck me when they get bad. Another thing with PRS matches is everyone wants to share wind calls. It was great for a beginner when we shot huge targets to get on steel. Once you get to a certain level, you will get everyone's .1-.3 mils of shitty trigger control with their wind call. You also don't know if they dialed in spin drift, or coriolis (I personally zero so my error (less than .1 mils) is to the left and ignore these until I am beyond 10 mils dialed on the scope). What I'm saying is, you need to make your own wind calls and tune everyone else out. Even if you are good enough you are trying to win the match, unless you are in a super squad, using the guy before you as a wind caller is usually more harm than good. All NRL Hunter stages are blind(ish) with no discussion of stage before shooting, so they are better practice. Matches get you the most different scenarios to practice, vs shooting at a square range where once you have the wind call, you just follow it from shot to shot.
3) If you have a place to do it, practice with what archers call roving. Walk around (or drive) and find a rock, dirt clod, etc to shoot in a safe scenario, make a wind call, and shoot. If you live where you can target shoot on public land then this might be easier. There's hardly any public land where I live, so I don't do this much with a centerfire. If you build an accurate 22lr it can be scaled down, but it is harder to have multiple terrain effects in the same shot when you are only shooting 200-300 yards.

There is some value in holding up a Kestrel, but once you have it figured out there is not a lot to gain on feel. If you observe what certain vegetation does in certain winds it is more helpful when practicing with the kestrel. Then you can observe at distance through glass when shooting. I can typically get within 1 mph of the kestrel up to 12-15mph. That's not very beneficial though, because I can pull it out and hold it up, and it will tell me the wind at my location. ( I might sort of be talking out both sides of my mouth here. In reality, unless the wind is over 10 mph, I never pull it out except to get an initial temp and pressure. Even yesterday, the wind forecast was 19 mph with gusts to 26 and I never pulled it out. We were culling does and managed to get 4 hunting with my 8 year old daughter. (We shot 2 each.) The wind calls were pretty large.)

That's how I practice and apply it. Like I said, I'm good, but not great. I live in the midwest where we have some big, steep hills, but they "ain't no mountains." Some wind effect still kick my tail, so I'm interested in hearing how others deal with big winds in rough terrain.

 

[RS_Non-Res]

I'm not good at wind calls while shooting, but this book helped a ton while I was sailing. Walker explains principles and systems and then puts them into practice in various seasons and different places around the world. And yes, sailors need to think about 3D wind movements and periodic shifts. Maybe Walker's principles apply here too?

The Sailor's Wind Hardcover – May 17, 1998​

by Stuart H. Walker (Author)

Poached from Amazon: Sailors from novices to experts will treasure this simple yet authoritative guide to the winds. Stuart Walker's intelligent, straightforward explanation of why wind behaves as it does and what it is likely to do next draws upon his sixty-plus years of sailing experience and his vast knowledge of meteorology. The Sailor's Wind first describes each aspect of wind behavior in context—challenging readers to analyze wind flow as though they were experiencing it on the water—then explains what principles determined the wind's behavior, using recent meteorological research, instrumented observations, and studies of computer models. This book enables sailors not only to understand the wind but also to harness it.

 

[solarshooter]

I thought up a bit of a drill I'm going to try with some buddies next time I go out east to shoot long range. I want to set a gong target up in the middle of an open safe shooting area with a vitals sized steel plate. Then one of us leads and the others follow, the leader can take whatever path they choose up any terrain in any direction. At some random point the leader calls "shoot", and the other has 2 mins to execute a shot on the gong. This is with packs and rifles and any relevant gear that would be used hunting. The range, wind call, and result is logged. Now the shooter leads, again on a random path, and eventually calls "shoot". And so on and so forth.

Seems like a time efficient way to get many realistic shots on target in varying conditions. Also would give an opportunity to build up some data on an effective hit rate in as close to real conditions as possible. We'll see how it works out.

 

[HighUintas]

I thought up a bit of a drill I'm going to try with some buddies next time I go out east to shoot long range. I want to set a gong target up in the middle of an open safe shooting area with a vitals sized steel plate. Then one of us leads and the others follow, the leader can take whatever path they choose up any terrain in any direction. At some random point the leader calls "shoot", and the other has 2 mins to execute a shot on the gong. This is with packs and rifles and any relevant gear that would be used hunting. The range, wind call, and result is logged. Now the shooter leads, again on a random path, and eventually calls "shoot". And so on and so forth.

Seems like a time efficient way to get many realistic shots on target in varying conditions. Also would give an opportunity to build up some data on an effective hit rate in as close to real conditions as possible. We'll see how it works out.

I'd thought of something similar that. Use a couple of vital sized steel plates that can be packed. Go with a buddy or two and organize some type of leap frogging deal across canyons with the plates, alternating shots. Minimizing backtracking of the setter while staying out of range of an errant shot would be harder to figure out