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Do we care more about, SD or ES?
- Thread starter Golfnut721
- Start date
I think we all get passionate about things we love to do.
Our club range has 300-600 steel. I tried once just for giggles to shoot the 300. I used a variety of ammo all sub-par leftovers just to burn up. watching where POI by the puff of dirt I walked in the rds. and started hitting the steel consistently I had about a 12-14" vertical dispersion. but I wasn't impressed as the steel is 16x16 I believe. I am so used to trying to hit a 1/32 dot not sure how big the steel is for PRS competition.
Lee
I typically put a 12” square at 308 yards. Sometimes a 12” round. A 10” round at 300-305. These targets will usually be only a couple of those for a stage. Typically there will be a 6” or two in the 200*/- range and another shorter range target.
Maybe start with two shots on each of one or two targets at 308, then two shots at 200-ish, then somewhere between 100-150. Then back to 200 or 300, depending on the day. This in usually 105-120 seconds off a rooftop or barricade of some sort.
If you actually just shot these few hundred rds at selected distances, would you now not Know what the best the rifle and ammo could do? Probably see close to the worst also.
First sentence is quite a revelation.
On knowing the number, just what does it actually prepare you for?
If we suspect the high and low rds of the brick are in the 3 boxes of ammo we choose for the day, are we going to shoot bigger targets out of fear of failure?
I would bet a fair amount of money, when you first started shooting 1/32" dots at 50 yards, success was not immediate.
By contrast, you failed to pay any dues prior to or the day you lobbed not so stellar ammo at 300 yards. Keep things in perspective here.
The first sentence is obvious to MOST. Please see the genius quote below if you think it’s obvious to all.
Knowing the minimum vertical dispersion gives you a goal to reach for. A way of gauging other factors such as wind reading, trigger pulling etc.
The fact that you ask the question is proof that you cannot or will not find merit in the answer.
Not everyone gets emotional about these conversations. Personally it’s like watching an old three stooges episode. I marvel at the lack of comprehension, the promotion of ignorance over information.
Ok, first off, you said if you know numbers, you can predict. I said, shoot it and know.
As you are questioning my intelligence, don't think for one minute the reverse isn't going on here.
What you see shooting is the additive effect of every condition of wind, mirage, every hold error, every rest error, every trigger mistake, shoulder push all added together with the minimum vertical dispersion. This is fact.
Without data you have no idea what you could achieve.
Again, you choose ignorance over fact. Your choice.
If you could answer two simple questions logically it would clarify your position.
What do you think of the claim:
“ …because what I can achieve with a tuner is against physics!… “
Why would you not choose to have the best data possible?
Without data you have no idea what you could achieve.
Again, you choose ignorance over fact. Your choice.
If you could answer two simple questions logically it would clarify your position.
What do you think of the claim:
“ …because what I can achieve with a tuner is against physics!… “
Why would you not choose to have the best data possible?
I don't recall saying that I defied physics with a tuner, I have said, I kept adjusting a tuner the further out that I shot, and the results I got were satisfactory and remain so for that lot of ammo.
I am not against data at all, I use it all the time in CF cases.
Because I said that I would rather shoot my best vertical at say 450 and know, compared to you wanting to predict it through numbers. I am not getting how you feel that you, or your method is superior.
The quote was from hv nv shooter. It appeared you were defending his position.
My point is it takes both to fully realize your potential. The data tells me what I can achieve with perfect execution. The target tells me actual (and very important results) The difference tells me how bad I am at this stuff. (Pretty bad)
Armed with both I have a goal. Close the distance from where I am and where I want to be.
Hope that makes sense. I share what I think is your disdain for “computer shooters” who don’t get in the dirt and launch bullets. I simply want the best information to build on.
My point is it takes both to fully realize your potential. The data tells me what I can achieve with perfect execution. The target tells me actual (and very important results) The difference tells me how bad I am at this stuff. (Pretty bad)
Armed with both I have a goal. Close the distance from where I am and where I want to be.
Hope that makes sense. I share what I think is your disdain for “computer shooters” who don’t get in the dirt and launch bullets. I simply want the best information to build on.
In the scope of long range 22LR, say, knowing or predicting your best vertical dispersion really means jack shit come adverse conditions, botched shots, etc. Wouldn't it now be more beneficial to know the worst dispersions both horizontal and vertical possible in conditions you are familiar with in order to adapt to what is going to happen?
If it seemed like I was defending HV NV, I maybe agreed with a stance, but in all honesty, if you do not shoot long range 22LR, absorb and keep the discharge to a minimum. 50 yard fudds bring nothing to the table.
I like your rifles too much to want to argue with you, take your finger off the button, lol
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Depends on who you ask about tuners.
Those who are using them for positive compensation claim to overcome significant ES.
There are people on this forum who claim they can compensate for 100fps ES @ 1k yds with a tuner. For centerfire.
Not saying they can or can’t. But there are definitely people who believe they can fix a large ES with a tuner or positive compensation in general.
If you’re using SD, then yes, you’d be pretty close to “knowing.”
For example, if you shoot 200 rounds with a 7sd, then your sd will be between 6.4 and 7.8 95% of the time.
However, you may very well not see your true ES. There’s still a 5% of your shots that will be up to 47fps.
So it would be extremely easy to not see your true ES because you randomly don’t have those 10 shots in those 200 rnds.
Just pointing this out since the OP asked about SD vs ES.
Which also means the target isn’t showing you everything possible either. Which is why a chrono is also important.
For example, if you shoot 200 rnds on paper without a chrono, you have no idea if your worst possible shots are included.
However if you use a chrono, get an sd of 7, but an ES of 28, you know you likely don’t have the worst possible shot in ther.
If you shoot 200, have an sd of 7 and an ES of 50, then you know you very likely have the worst in your group.
And yet another way the target can “lie” is when a round is on the high end of your ES but high end of your BC variance. And vice versa.
This is one of the main culprits of people who “just look at the target” think they have come across something like positive compensation. Without lidar/radar or other things that help solve the things like BC we can’t measure with chrono or target….we are limiting our ability to make logical deductions.
So, having a chrono along with the target allows us to make informed decisions with as much data as possible. And by default, SD is the superior stat for the chrono side of the equation.
This is one of the main culprits of people who “just look at the target” think they have come across something like positive compensation. Without lidar/radar or other things that help solve the things like BC we can’t measure with chrono or target….we are limiting our ability to make logical deductions.
So, having a chrono along with the target allows us to make informed decisions with as much data as possible. And by default, SD is the superior stat for the chrono side of the equation.
Being a confirmed and resolute 50yd FUDD I wasn't about to be the one to raise the topic of BC variance but at long range it must become a significant factor. Does anyone have data for BC SD and ES? It might give us all something more to think about if we knew as much about BC variance as we do MV variance for different ammo grades. What say ye good gentlemen of the HIDE?
I'm a dumbfuck, but I am going to say the rds within the SD range will hold better vertical, and subsequently some horizontal. Tighter SD means more shots in the desired area. No control over highs and lows.
We zero our rifles and gather dopes off the larger norm, not the fringes.
That is what I would have thought too. I only bumped into it on another forum last week. The fellow was running a LabRadar to gather a dataset of downrange velocities and then (I think) using an online program to calculate BC and BC statistics. I will see if I can find it again when I get a chance but from his description it was not rocket surgery.
What little I know of bc variance,
is that that biggest variations occur in the transonic zone.
That'd be from about 1350 fps to about 900 fps.
Interestingly enough, that is the muzzle velocity range of most 22lr brands.
The information was part of an article by Sierra.
Had the link saved....
is that that biggest variations occur in the transonic zone.
That'd be from about 1350 fps to about 900 fps.
Interestingly enough, that is the muzzle velocity range of most 22lr brands.
The information was part of an article by Sierra.
Had the link saved....
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It's very straightforward to collect SD and ES data. It's not easy to calculate .22LR BC values. In any case, the former will have an influence greater than BC. Precision is non-linear as distance to target increases not because of BC variation but because of MV variation and Cg variation.
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Justin, the Sierra information relates to centerfire. If these are jacketed rounds, they will have much less BC variation than soft lead .22LR match bullets.
Landy, who probably knows as much about .22LR ballistics as anyone posting on forums, says the following
lead malleable projectiles will probably never be capable of having consistent BC's even within the same Lot, as can be done with jacketed CF projectiles. With CF, the variance or Standard Deviation for calculated BC's can be determined with about a +/- 1 percent level of accuracy.
With RF, due to obturation from ignition and the barrel changing the shape of the bullet, variations within even the same Lot will average around +/- 4 percent.
See post #18 https://www.rimfirecentral.com/thre...f-rifle-bullets.601764/#nested_reply_top_post
Yeah G, but that's the little I have read regarding variations
when understanding ballistic coefficients.
Most of the BC formulas I found appear to be averaged,
not calculated for individual moments in the trajectories.
Close enough for my drop calculations, when trying new cartridges.
when understanding ballistic coefficients.
Most of the BC formulas I found appear to be averaged,
not calculated for individual moments in the trajectories.
Close enough for my drop calculations, when trying new cartridges.
I am not trying to be a smart ass and your conclusion is incorrect. to put things in perspective regarding my shooting before I started shooting RFBR I shot groups a lot of groups during all conditions. the reason there was no class for me to shoot local in RFBR I waited 4 years to shoot UL. this was back in 2017 since then I have won our UL club championships 5 consecutive times now. 2021 I set a club record by winning the season before it ended. how I did it was we shoot 12 matches for the season and use the best 7 match scores for the total points. 70 is max points you can earn. I won 7 straight matches nobody did it since they started shooting RFBR over the last 12-14 years. so, by July I had it all wrapped up. that year was also my best and I topped it off by finishing 2nd behind the number one ARA shooter that year. yes, he kicked my butt and beat me by 1100 points, but he beat 3rd and below by 2200 points I beat 3rd and below by 1100 points. there also were two other shooters who finished that year in the top 25 across the nation in ARA.
so, my dues have been earned maybe not in distances past 100yds. but measured by how many ARA matches I have shot since 2017 with 3rd and 5th place being the worst I have finished. in the past 6 years I have shot less than 70 sanctioned ARA targets and I believe in 9 or 10 matches with 5 wins. so, I am not a newbie shooter. just for long distances.
Lee
Let me put in the correct context. I am not claiming I can defy physics. I have been accused of saying / claiming this because of my claims of not having to adjust my tuners on my rifles regardless of temperatures, humidity etc. one of my rifles a 1411 Anschutz has not had the tuner moved in 8 years yet I can shoot various lots of ammo and they will shoot near same POA/POI I don't have to also make adjustments for distance granted I only shoot to 100yds. at the most.
I was told this is impossible, but yet there are many RFBR shooters who can do the same. are we all defying physics? what a lot of shooters who start to use tuners do not realize or perhaps don't understand a tuner is used to time the bullet exits from the barrel. and the exit needs to be at the highest point that barrel can achieve. by doing this you can minimize some of the SD/ES, so POA/POI is nearly the same across a wide range of ammo lots.
now don't mistake this as I am saying a lot of ammo with a big SD./ES can be made to shoot good. junk ammo will still shoot junk maybe not as bad in a properly tuned rifle but still bad.
anyway, that is what I meant about defying physics.
Lee
There is no such thing as 100 % positive compensation. the best is partial, and I am talking about rimfire since you can't alter the load. if one could achieve 100% PC any decent lot again rimfire would shoot same POA/POI as any variances in velocity would be equalized with true 100% PC
Lee
Sorry about the misjudgment on your initial BR accomplishments. It has been apparent by the groups you post, you are on the ball! Take that as a compliment.
But yes, the paying the dues comment was indeed meant for shooting distances, nothing else.
No apology needed. Thank you, my initial success in BR I believe is from all the time I spent shooting groups and learning my rifles. I surprised myself as well.
but yes, learning more about longer distances is something I need to do.
Lee
I want a sound SD that predicts a decent average velocity so I can make solid guesses using a ballistic calculator for come ups at the random ranges target are set up in a match. It’s an odds game with Rimfire. Long ranges and small targets mean depending on ammo, 5-10% will fall outside the norm and hit dirt. Stability at long range vs faster twist sensitivity to non uniform projectiles is another rabbit hole of complicated odds simplified to a SWAG.
I figured you had to be a serious BR shooter and BTW congrats on your achievements.
The dedication to be a national level champion I find astounding! The guy who won the national BR N50 is a friend, well more than a acquaintance anyway. He builds Thomas pcp air rifles and he literally shoots enough pellets and slugs/(pure lead swaged bullets) to fill a 5 gallon bucket/a 100,000 or more in a years time so he's shooting and testing many hours a week.
Turns out one can get pretty good in the wind, both in the horizontal and the vertical, with that much trigger time. On top of this he's just a bulldog in personality. Man he don't let go until he's figured things out and its continual in incremental improvements past that. His guns which were totally awesome years ago are much improved over them nowadays.
Being a, I'll use the word "tactical" rifle based forum, the BR world isn't as well known around here.
Story=It was funny one time for me here at SH. Some guy with apparently more money than sense wanted a true 1/4" all day long rifle at 100Y, and about that good at distance, so a/that particular thread ensued after getting a dud of a custom 308 tactical rifle, thus he was now looking for the best of the best.
I suggested he get a Wheeler custom BR rifle in 6mmBRA, and well the other ancillary items needed to achieve such groups on a regular basis. I think one of Wheeler's rifles won 1000Y BR that year but I can't remember exactly, however these were definitely as close to that task as could be had at the time??
What happened is I got flamed by the Fan Bois of top of the line 308 tactical rifle world, LOL. I had absolutely nothing against this smith or his rifles, as well he seems like a great guy, but I was just pointing out what was actually needed to achieve the OP's objective as close as possible.
That being said I'm no BR shooter per say but I can read BR stats and match results.
Another funny thing was that shortly after this, 6mmBR, 6mmDasher, and 6mmBRA, started to become popular in the "nowadays they call it" the (Precision Rifle World).
Don't say "tactical" rifle these days or the dog pile is coming because that's not cool anymore, LOL!
Back to this thread.
IMO the most optimal ammo has every positive attribute we can think of or results go down from there in one way or another. The question is how much, time, effort, and money, does one want to spend to find that special lot#/number of it. Me, nope not gonna go there. What a relief.
Old thread, but on an SD kick lately and hadn't seen this question. Extremely simple concept. SD takes every available data point into account. ES only takes two.
Even in shot strings as small as 5 shots, when you use ES, you are essentially ignoring 60% of the data in favor of 40%. As shot strings become larger, you continually ignore more and more data.
Since ES is a fixed sample size of exactly two, you will also see much more extreme variance affecting the numbers. For example, if you let a round cook in the chamber by accident, your ES will increase significantly, but with proper sample sizes.....your SD will not make such a dramatic change.
This is why basically no other portion of society uses ES. If you do a simple google search for ES, it will be almost only rifle related returns. Because people have perpetuated the use of a terrible stat so much in one area, that's the only place you'll find it.
Here is just a very small and easy example how looking at your ES only can easily lead you in the wrong direction. It's very likely in the left sample the 2840 round was due to something out of the norm. Where the two 2830 rounds in the right column are more indicative that 2830 is a speed you will see a decent amount.
If someone were to use ES as the determining factor, they would likely be making the wrong choice. If they are using SD, and using it properly, they would realize the difference between 14 and 16 isn't significant and would either not make a decision or they would look further into the specific velocity numbers and see there is a very real chance something happened with he left shot string and it may in fact have a much smaller SD and thusly ES.
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The TLDR: when you use ES, and use shot strings of 3 shots or more, you are essentially tossing at least 33% of your data in the garbage. Once you get to shot strings of 5, you are throwing 60% in the garbage. Once you get to 10 shots, you're throwing 80% in the garbage. At 30 shots, you are throwing 93% of your data in the trash can.
That's just a terrible idea in general.
Geeze, talk about information overload!
What equipment are you folks using that not only shows impact location on target but also velocities?
In some of the pics I’m seeing what I’ve personally experienced:
A slug of a certain velocity always prints in a certain spot on the target, the group size of other rounds of that same velocity being based on both the precision potential of that given combo, conditions, and shooter ability. Fire your box of ammo say, at a 100yd wind shielded or indoor range, with no more than say 5 rounds per bull on a 25 bull target. Call your shots/own your errors and note them on each errant impact, but then analyze your collection of 10 targets.
Let’s say you have 10 shots that were 1080fps, 5 @ 1085, 5 @ 1075, and on and on so you have a set of extreme highs and lows, with the majority of those being in the middle of the velocity range.
Selecting say, a sample velocity of 1078, I’m betting every shot that pinged that speed fell close to the same spot on each target. Let’s say all those rounds would make a group the size of a nickle. Now select another random velocity that you have several rounds clock at, I’m thinking they also would make a similar group.
And on, and on. Those assorted group’s overall size would represent the cone of fire or precision potential of that barrel-ammo combination.
Am I wrong?
Is this where tuning comes in? Now that you have your collection of velocity based groups, you tune for the highest precision from your largest available velocity sampling size?
Next you must test a different lot or type or brand of ammo to see not only if those identical velocity rounds represent a substantially higher proportion of rounds per box, but also hopefully group even more precisely?
What equipment are you folks using that not only shows impact location on target but also velocities?
In some of the pics I’m seeing what I’ve personally experienced:
A slug of a certain velocity always prints in a certain spot on the target, the group size of other rounds of that same velocity being based on both the precision potential of that given combo, conditions, and shooter ability. Fire your box of ammo say, at a 100yd wind shielded or indoor range, with no more than say 5 rounds per bull on a 25 bull target. Call your shots/own your errors and note them on each errant impact, but then analyze your collection of 10 targets.
Let’s say you have 10 shots that were 1080fps, 5 @ 1085, 5 @ 1075, and on and on so you have a set of extreme highs and lows, with the majority of those being in the middle of the velocity range.
Selecting say, a sample velocity of 1078, I’m betting every shot that pinged that speed fell close to the same spot on each target. Let’s say all those rounds would make a group the size of a nickle. Now select another random velocity that you have several rounds clock at, I’m thinking they also would make a similar group.
And on, and on. Those assorted group’s overall size would represent the cone of fire or precision potential of that barrel-ammo combination.
Am I wrong?
Is this where tuning comes in? Now that you have your collection of velocity based groups, you tune for the highest precision from your largest available velocity sampling size?
Next you must test a different lot or type or brand of ammo to see not only if those identical velocity rounds represent a substantially higher proportion of rounds per box, but also hopefully group even more precisely?
