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Rifles, Reloading, Optics, Equipment
Reloading
Load Development Interpretation
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<blockquote data-quote="QuietTexan" data-source="post: 2526457" data-attributes="member: 116181"><p>A rough rule of thumb is that a valid ES is ~5x of SD. There's a lot of math behind making that number 5 and not 6, but looking at a normal distribution 99+% of data points happen within 3 standard deviations of the mean, meaning within 6 total standard deviations. Until the two stats start to normalize they don't have much inferential value.</p><p></p><p>Two things to think about here: one is that ES uses the least possible number of data points - two of them to be exact - and since those two points are the highest and lowest they're the most susceptible to being outliers. That means ES is the weakest possible statistical comparison with the least inferential value.</p><p></p><p>Second builds on that last point - ES will almost never provide positive confirmation of anything (since to be practical we're limited to reasonable round counts), at best it provides negative confirmation in small data sets. One place this is useful is roughing in a barrel tuner - if you shoot pairs you can say that while the aggregate group of a much longer shot string might get larger than the pair, it can never get smaller than the pair. So you rule out tuner settings that have too large of an ES and move on. That doesn't help you prove any given setting is actually good, to do that you have to increase the number of shots. So I'll sit there and turn the tuner to a setting, shoot two, and either move on if the group is too large, or continue shooting until the group opens up.</p><p></p><p>Clear as mud? <img class="smilie smilie--emoji" loading="lazy" alt="🤣" title="Rolling on the floor laughing :rofl:" src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f923.png" data-shortname=":rofl:" /> Stats is very important to shooting, but it's also a very, very easy way to misrepresent information. One problem is that it can set impossible goals because everyone on the internet can shoot a1SD/1ES group... they don't really say it was three shots, or they ignored "flyers". Don't chase a ghost, look at the paper targets and do what they tell you to do.</p><p></p><p></p><p>New brass is going to have some case to case inconsistencies, even coming from the best brands. They're manufactured to be very consistent overall but until they're shot there's no telling how each will respond to what happens inside of the case. It can be tough to shoot through all your cases with tight components now, but the second and third firing are probably a better place to get muzzle stats. Then the real crazy happens - SD and ES might start opening up , yet groups will stay consistent if you tune the load right.</p><p></p><p>Managing muzzle velocity variation is critically important - but very dependent on how far and what you're shooting.</p><p></p><p>ELR/ more than 1000 yards - very important.</p><p>Shooting really small targets/ trying to make first round hits anywhere past 600 yards - very important.</p><p>Match shooting where you get to shoot sighters and can re-dial your scope before shooting for score under 1k - not very important.</p><p>200 yards - literally will never matter - unless you're making loads so unsafe that you shouldn't be loading at all <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite9" alt=":eek:" title="Eek! :eek:" loading="lazy" data-shortname=":eek:" /></p></blockquote><p></p>
[QUOTE="QuietTexan, post: 2526457, member: 116181"] A rough rule of thumb is that a valid ES is ~5x of SD. There's a lot of math behind making that number 5 and not 6, but looking at a normal distribution 99+% of data points happen within 3 standard deviations of the mean, meaning within 6 total standard deviations. Until the two stats start to normalize they don't have much inferential value. Two things to think about here: one is that ES uses the least possible number of data points - two of them to be exact - and since those two points are the highest and lowest they're the most susceptible to being outliers. That means ES is the weakest possible statistical comparison with the least inferential value. Second builds on that last point - ES will almost never provide positive confirmation of anything (since to be practical we're limited to reasonable round counts), at best it provides negative confirmation in small data sets. One place this is useful is roughing in a barrel tuner - if you shoot pairs you can say that while the aggregate group of a much longer shot string might get larger than the pair, it can never get smaller than the pair. So you rule out tuner settings that have too large of an ES and move on. That doesn't help you prove any given setting is actually good, to do that you have to increase the number of shots. So I'll sit there and turn the tuner to a setting, shoot two, and either move on if the group is too large, or continue shooting until the group opens up. Clear as mud? 🤣 Stats is very important to shooting, but it's also a very, very easy way to misrepresent information. One problem is that it can set impossible goals because everyone on the internet can shoot a1SD/1ES group... they don't really say it was three shots, or they ignored "flyers". Don't chase a ghost, look at the paper targets and do what they tell you to do. New brass is going to have some case to case inconsistencies, even coming from the best brands. They're manufactured to be very consistent overall but until they're shot there's no telling how each will respond to what happens inside of the case. It can be tough to shoot through all your cases with tight components now, but the second and third firing are probably a better place to get muzzle stats. Then the real crazy happens - SD and ES might start opening up , yet groups will stay consistent if you tune the load right. Managing muzzle velocity variation is critically important - but very dependent on how far and what you're shooting. ELR/ more than 1000 yards - very important. Shooting really small targets/ trying to make first round hits anywhere past 600 yards - very important. Match shooting where you get to shoot sighters and can re-dial your scope before shooting for score under 1k - not very important. 200 yards - literally will never matter - unless you're making loads so unsafe that you shouldn't be loading at all :eek: [/QUOTE]
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