Measuring Precision: Extreme Spread is Dead! - Ep 14
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- เผยแพร่เมื่อ 24 ส.ค. 2024
- The episode is all about using a better tool to measure the precision of your rifle system.
A HUGE thanks to RB for all his help and wisdom; and for encouraging me to put this video together to help others.
Good on ya, Ben.
A broken clock is right twice a day! I like his proverb and will be using it from now on :)
Here in Canada and the US, ES-extreme spread is calculated using a chronograph. Taking the fastest speed of your five, ten shots and subtract the slowest speed of the same five or ten shot groups. The best I can get so far is 20 fps between five shots.
@staffordshires2, I think you may have the subject of this video confused, or may not have watched the entire video. This video is about measuring the precision of your weapon system (group size), and using better tools to measure that precision like Mean Radius, instead of using the extreme spread of the group (group diameter).
I do have another video on the channel which deals with ammunition and velocities in more detail which you might find interesting. It’s Episode 18 called “Is your ammo letting you down?”. This video does deal with Standard Deviation and Extreme Spread of velocities in the context you are referring to.
Thanks for watching and I hope you enjoy the other videos on this channel 🇦🇺👍🏼
Good info Ben. As an F-Class shooter, both precision and accuracy are needed in order to be competitive. A lot of competitions are won on super X counts with competitors equal on score count. Having a good centre count to your groups is very important in order to get to most Super X's. A load that holds 1 moa to a every range out to 1000 yards is ok but if it has a hollow centre it will not score a lot of super X's and you will be unlikely to finish in first place. So what Ben is talking about is exactly what F-Class shooting try to obtain when doing load development. The shot dispersion pattern of the particular barrel/load combination is very important. The same applies to any form of rifle shooting competition where you shoot for score.
Good video! It's great to see a little bit of statistical reality in the shooting world for a change :).
One issue to consider: you say at 9:58 that mean radius does not need to be scaled like ES does. No disrespect intended to Mr Litz, but this is incorrect. The MR of any given group of size n will always underestimate the "true" mean radius of the underlying distribution -- this is due to the fact that the MR of the individual groups are calculated from the center of the group, not the true center of the distribution (which will always be further from the observed points of impact than the center of the observed group). In other words, the mean radius of an n-shot group is a biased estimate of the mean radius of the underlying distribution. And just like the ES, the bias gets smaller as n gets larger.
I'm also skeptical of the idea that you can simply multiply MR by 2.1 to get the 95% probability area. It's been well-established in statistical theory that you can multiply the Circular Error Probable of the underlying distribution by 2.1 to get the 95% confidence area. But 1) the CEP is not the same as the MR and, 2) more importantly, we don't know the CEP of the underlying distribution. All we know is that the MR of a given group underestimates the true MR.
That gripe notwithstanding, the method that you lay out is WAY more reliable than the common ES methods. Thanks!
oh good I am not the only one that hangs up targets on the fridge.
Really great video that gives a more true understanding on how precise a rifle/shooter is. I’m noticing that there is a definite segment of the precision rifle population who doesn’t want to hear the statistics.
Good stuff! The visual explanation of the 2 shooters and their subsequent shots made the concept click into place for me.
Great stuff Ben - well thought through and well presented. Love your content mate - keep it coming
Mind-blown. Thank you this will be putting me down the rabbit hole!
Thx that was a good perspective.
This video was incredibly useful! Always glad to see a new video of yours :)
very good video mate. About time someone showed this
Yeah awesome. I’ve watched a lot of shooting videos now but none have covered what you have just presented. Blown away your channel is not bigger. Great work.
Excellent work Beno. Delivered in a concise and digestible way - mission accomplished 👌
excellent communication and not afraid to get technical. hands down the best explanation of this stuff I have seen on this site. subbed.
Hilarious. Only saviour to ole mate is he drinks IRONSIDE Coffee.
Struth 😳 my heads spinning, now where did I put my scientific calculator 🤔 , this shit is getting complicated. Well done , great video Ben .
Excellent article. Lots of substance.
Great stuff! Appreciate the help in managing my long-range expectations. God bless!
Nice one champ lots of info.
Awesome info Ben 👍
Great video; very helpful. Thank you
8:53 multiply your mean radius by 2.1, then multiply that numbrr by 2 to get your expected diameter.
Correct 👍🏼
@@TheLongGunProject that data was hard to find. I spent a couple hours going through videos and articles to find it. Much appreciated
@@jonathanrogers9961 thanks for taking the time to watch the video and follow up on the data mate. There is a lot of misleading info out there and I do my best to make sure I’m not putting out bullsh#t. When it comes to technical videos I get them double checked by some well qualified mates before making them live. Thanks again for watching and for your feedback, I greatly appreciate it. I hope you enjoy the other videos on this channel too 👍🏼
Great video mate
🤔🤯great info explained well like all of your videos
I keep watching videos talking about 'Mean Radius' but nobody explains how to measure it.
G’day RTmadnesstoo, thanks for watching the video. The easiest way to measure Mean Radius is to use an app on your smart phone that lets you tack a photo of your group, plot the impacts or holes and it works it out for you. I use the app called SubMOA which I mention in the video. It’s pretty intuitive and gives you a Mean Radius measurement every time. I hope you enjoy the other videos on the channel! 👍🏼
@@TheLongGunProject Yes, I've been looking through your other video and I find them both educational and entertaining. Thanks.
I understand there's an app that's relatively easy to use but I want to understand the mechanics of how it's calculated so I can understand why it's significantly better. It would help me with the 'Big Picture'.
Wish when i was at school i paid more attention in maths class instead of girls
So should the smallest groups always have the lowest velocity SD?? Mine typically do not. Would you choose charge and seating results based on SD alone?
G’day @jwschroeder804, thanks for watching the video and for the comment. In the video at 14.30 I cover the point you raise. The point make is correct; SD’s don’t equate to the smallest groups at 100yds or meters. I don’t choose charge or seating depth based on SD’s alone. I look for both precision and consistency for my long range and extreme long range loads. I cover these elements in more detail in episode 18 on my channel if you feel like checking that out. Thanks for watching and commenting and I hope you enjoy the other videos on this channel 👍🏼
@@TheLongGunProject I’ll review that portion. I’ve been stuck on that point because most of my shooting to date has been short range. Thanks.
Out of curiosity where does the 2.1 value come from?
G’day @Haris122, the 2.1 value is used to expand our Mean samples (in this case Mean radius of our group) out to 2 Standard Deviations. On a standard distribution graph like a Bell Curve, 2 Standard Deviations makes up 95% of the curve area. 95% gives us a high degree of confidence in the expected outcomes we will see downrange. A more detailed and in-depth explanation of this can be found in Modern Advancements in Long Range Shooting Vol 2 by Applied Ballistics.
Thanks for watching the video and I hope you enjoy the other videos on the channel 🇦🇺👍🏼
Why are you multiplying you MOA by the distance at 6:56 to say you would have more MOA at 500 yards? MOA is an angular measurement and is irrespective of distance. You recover in your calculations at at 7:16 by NOT multiplying by (546y/100y) to calculate the expected shot spread at the far target. Right(ish) answer but the math is all messed up. The MOA that the rifle is launching the bullets at is the same at a 100 yard target and a 546 yard target. However, the distance that angle acts on the horizontal and vertical spread is the key factor in this calculation.
I say right (ish) because the MOA angle of the exiting bullet is only one factor. Factors such as variations in muzzle velocity or bullet deformation have a greater effect at 546 yards than they do at 100 yards so you won't have the same MOA performance at distant targets, though generally the simplification you are making is a starting point...
G’day Brett, thank you for your feedback. The aim of this video is to open shooters up to the idea of using statistical maths to get a better and more realistic understanding of what their rifle, their ammunition and they are capable of on an average day.
I think you might have missed a few things I was saying in the lead up to 6:56, which might have caused confusion. The reason I was multiplying MOA of a group size was because I was scaling up a 3 round group to represent a 10 round group as part of the example I was making. It is the same example used in Modern Advancements in Long Range Shooting Vol II published by Applied Ballistics who I reference throughout the video.
You’re correct that MOA is an angular measurement which doesn’t change regardless of distance. I am not disputing this fact in the video. The point I’m making in the video is that using Mean Radius is a better way to measure (and accurately predict) the precision of our rifle system on any given day. I triple checked my maths and had a firearms industry R&D expert double check my maths as well. The maths is correct.
There is a lot of material covered in this video and if it’s not easy to follow that maybe due in part to my accent and the speed at which I talk. I hope you’ll give the video a second look if you have the time. Thank you again for your feedback and for taking the time to interact. I hope you enjoy the other videos on the channel.
All the best. Ben 🇦🇺