www.the-long-family.com/OBT_pa... Visit my website for hardware and software that will help you achieve your competitive goals. www.ShootSmallGroups.com
I am addicted to this podcast, love the info i get from it. 100s of years of collective wisdom and experience shared... thank you Erik for what you are doing for the community
Erik, you are doing the shooting community a lot of good, with scratching open all these golden nuggets for the broader community. Thank you. The Long-family's work and the combination Gordon's GRT add to it is absolute magic. Thank's Chris and RIP Gordon.
I have been a distant (South Africa) follower of Dan Newberry and the Chris Long developments for some time now. Chris was even kind enough to entertain a couple of my emails and to answer these to clear up confusion that I had. It was so awesome to see you feature them, lovely to put faces to the names. Awesome podcast, true leaders in their fields, like you, always give back to help the sport grow. Many thanks Erik.
Thanks Erik for posting, especially when it includes individuals that have applied their formal technical/engineering related background towards the enjoyment of improving their hobby and sharing their results. I’ve utilized the OBT concept in the past from Chris’ web page and especially Gordon’s reloading tool to get me in a fps ball park window for my combination of barrel length, case volume to powder ratio, etc... We have so many variables at play from trigger to target but all worth the effort when withnessing that cloverleaf at distance! On Varmint Al’s web page, he has sharred his analysis on barrel harmonics which for me was also a great read. Again thanks for your videos.
I love listening to Chris explain his thoughts and experiences with load development. He and I must be about the same age. I got my BSEE degree in 1981 but I spent 4 years in the Air Force first. Chris got his graduate degree in 1980.
The modes Chris is talking about is actually called order harmonics. So first order harmonic second order harmonic and so on. You have even and uneven harmonics which can amplify each other .
I've been visualizing a "donut", ie a wide spot, moving down the barrel from the explosion and reflecting back. It's not an expansion, it's a contraction. His background in RF gave him the insight to figure out what was happening. Standing waves are a big part of RF transmission. Thank's for doing these videos Eric. Slowly but surely this is starting to make sense.
Good ole Matlab. This guy seems to have a very strong grasp of internal ballistics. Great podcast. I like it when we get into the weeds about the subject. Ballistics are such an awesome topic and interesting science. I reckon Ima bout to have to spend a whole lotta time in Quickload and reading a paper on a topic I had no idea existed. I knew about the concept, but I had no idea there was all this extra information. Chris, thank you for taking the time to speak and share your knowledge with us.
I have been using the OBT model for many years, and I have a lot of faith in it. It works. It requires some work and constant tuning (trueing Quickload), but I enjoy the challenge. I'm not looking for F-class precision...MOA of Coyote is fine with me.
Thanks guys!!!! I always test temp to MV for temperature variation. It’s very necessary to know the correct mv and run it in the ballistics wether in a ballistic computer or in an analog computation. The case volume matters here, the same powder in different size cases will have a different burn rate vs mv per every 1 deg of change. Loving these videos!!!
Fantastic interview with Chris no doubt. Love these load development videos. Very educational and helpful. Question. What is the proper way to test primers ?
Any shock impulse occurring at the chamber will not only travel forward to the muzzle, but will also travel backwards. The backwards wave will then reflect forwards before the primary forward wave reaches the muzzle. This reflected rearward wave will arrive at the muzzle slightly after the primary forward wave does, and will be out of phase to some degree. The primary forward wave as reflected will travel through the secondary forward wave and the amplitudes will be algebraically summed together. That means the combination could be additive or substractive at the point of intersection. This reflection pattern will continue to repeat itself at reduced amplitudes until the energy is dissipated by molecular friction until it is no longer significant. It is similar to Standing Wave Theory in electronics. Therefore, the effects would be almost completely dissipated by node 2 or 3. So if the bullet does not travel down the barrel at such a speed as to arrive during node 2 or 3. the effect will be dissipated to uselessness. How many 6000 fps bullets do you know of?
Hello Eric. Love every podcast. At the end of this pod cast you mentioned people saying a bullet likes a particular speed. I have been mowing through my last 34 years of experience in loading and shooting and the only thing I can come up with having to do with Bullet liking a particular speed is the proper rpm range that the bullet likes and needs to stay stable not particularly the speed. Anyway keep up the great videos.
Can I ask a question that I can’t seem to find an answer for?: In regard to OBT on an AR15, what effect does the gas block/gas tube and flash suppressor have on the OBT chart? Thanks a lot for the great videos!
Chris says a 70-80 fps change in muzzle velocity for 2 different powders both in tune. Does this mean you have tuned at different OBT nodes (since the MV has changed) or does this mean that you hit the same OBT node even though the muzzle velocities are different. Seems like the latter could possibly occur if a different powder can result in a different acceleration profiles.
Yes you’re right . Different powders can have different muzzle velocities at the same barrel time. Due to different bullet acceleration which is dictated by burn rate and other powder voodoo
I find it interesting that Erik and many others seem to be overlooking something very simple with regard to this idea of “if it shoots at 100 but falls apart at 1000 then it has to be something with the bullet itself that needs to be improved because when it left the gun all was good, as seen by the results at 100.” While there could certainly be aspects of the bullet that need improving this is still a problem to be dealt with in the harmonics phase first. It is not something out of your control or to do with how perfect the bullets are. It is still a harmonics problem. If you have the hypothetical perfect bullet, with literally zero flaws, but still have a real-world load that has non-zero SD and ES, so each round still varies a little bit in velocity, if you tune everything so you’re getting groups at 100 that are as close to perfect as possible, with as little vertical on paper as possible, external ballistics DICTATES that the groups at 1000 will show more vertical. If it is a group at 100 that only has 0.1 MOA of vertical it WILL NOT have 0.1 MOA at 1000. But this is what I think Erik thinks. And this idea is wrong. If you have a load that shows 0.1 MOA at 100 but shows, let’s say 1 MOA at 1000 just for sake of conversation, i believe Erik is saying the reason that happens has to do with how the characteristics of the bullets are affecting the flight after it has left the gun. The problem with that idea should be very apparent if you sit down for a minute with a ballistics calculator. With a ballistics calculator we are able to examine the problem with the mythical perfect bullets that all have exactly the same shape, same weight, same perfect points and all other dimensions. We can’t test that accurately in real life because all bullets vary a little. So we will always have to question the results. “Maybe the difference is just because the bullets aren’t perfect.” Yes, that’s true. The bullets always vary a bit. But with a ballistics calculator we can look at the problem with the mythical perfect bullets at our disposal. Take the actual ES of one of your actual loads and use that to play with the ballistic calculator. If you have a load that averages 2850 fps, and you have an ES of 10, then punch that stuff into the ballistics calculator. Actually, I’m going to send this reply right now because I’m currently on my phone. I’m going to send and then move to my computer so I can do the ballistics calculator example myself to show the numbers it spits out. Then I’ll reply to myself with those figures in a few minutes here.
Weird, where'd my reply go with the numbers? hehe. Oh, maybe the URL for the ballistics calculator I used got it automatically flagged as spam. I'll try to write it again, and I'll leave the URL out, haha.
ok, I'll try to post this again without the ballistics calculator URL. Seems the first reply may have been automatically flagged as spam, and I'm assuming it was because it contained an URL. You can use any ballistics calculator to see for yourself. I used the JBM Ballistics one on their website, which already contained the bullet I'll mention in a second in its drop down menu for bullet selection. I'll try to remember the example I used and what I said... So, if I recall, Erik likes or at one point liked to use the Berger 184-grain .284 Hybrid Target bullets, though which bullet we use doesn't really matter. The actual numbers will change, but the fact that there is a difference will still show regardless of which bullet is used. Anyway, we'll go with the Berger 184-grain bullets. And I believe he may have stated that a load he was using at the time got these guys going about 2850 fps. An ES of 20 fps might be pretty typical, so we'll go with that, too. 2850 fps with an ES of 20 will give us rounds moving in the range of 2840 fps and 2860 fps. If we have a perfect 0.0" group at 100 yards with three shots, one at 2840 fps, one at 2850 fps, and one at 2860 fps, what happens out at 1000 yards when it is 0.0" at 100 yards? Bullet drop at 1000 yards with a perfect 0.0" 100-yard group: 2840 fps: -273.0" 2850 fps: -270.7" 2860 fps: -268.6" So with 0.0" or 0.0 MOA of vertical at 100 yards we will see 4.4" or 0.42 MOA of vertical out at 1000 yards for those same shots. It MUST show that much vertical at 1000 yards if there is none at 100 yards because of the different launch angles required for the different muzzle velocities to hit the same spot at 100 yards. A shot at 2840 fps will need a slightly larger launch angle than a shot at 2860 fps in order to hit the same spot at 100 yards. And the differing velocities and launch angles dictate that we will see a difference in point of impact out at 1000 yards, and with those speeds and the 100-yard zero that is how much vertical there will be. 0.42 MOA in this case. Now, how about we look at it from the other side? Let's look at it from the 1000-yard perspective. If we hit a magical 0.0" group at 1000 yards what does it look like back at the 100-yard mark? Bullet drop at 100 yards with a perfect 0.0" 1000-yard group: 2840 fps: +27.3" 2850 fps: +27.1" 2860 fps: +26.9" And again, at the opposite target distance we see vertical due to the differing velocities and required differences in launch angles. At this end we see 0.4" or 0.38 MOA of vertical at 100 yards with a perfect 0.0" group at 1000 yards. This is why you cannot get the best results at 1000 yards by tuning the load at 100 yards. A perfect group at 100 yards will have unwanted vertical at 1000 yards because that's just how ballistics works. You could try to test this in the real world if you have two ShotMarker systems and you set one up at 100 yards and the other at 1000 yards so that you are shooting through both of them at once. You will then have to contend with real world weather conditions, so you will not be able to see exactly the same results as you will get with the ballistics calculator, but you should still be able to see how tuning for 100 yards negatively affects the 1000-yard results, or how tuning for 1000 yards negatively affects the 100-yard results. It is too bad electronic targets for rimfire are so expensive, because you could do a similar test in a tunnel with two electronic targets and eliminate the wind factor. (Last time I looked they were something stupid like $15,000 each!) One at 50 yards and one at 100 yards with a 22 LR bench gun tuned for 50 yards would show the same effect. Tuning so the groups are as small as possible at 50 yards will introduce vertical at 100 yards, and vice versa. That's just how ballistic physics work. And this is why you must tune at competition distance in order to get the best results. If you tune at a different distance you are introducing additional vertical at competition distance.
How can the rifle change the flight of the bullet 100 yards from the barrel? Beyond 100 yards any change in group size can only be the bullet and the wind. I pretty much agree with Erik. However I would not argue that if you could then get the bullet shooting a tighter group at 100 then the bullet may be more stable and therefore shoot better at 1000. But as Erik says once you are getting one hole groups at 100 and larger moa groups at 1000 it can not be the gun.
@@billclifton8400 I suggest you re-read the comment with all the numbers. It doesn’t change what happens after passing 100. What happens at the muzzle determines what happens at 100 and 1000, but as the numbers show, what happens at 100 and 1000 with varying bullet velocities is different at those distances. It has to be different because that’s how ballistics works. It isn’t only the bullet and the wind. It is the angle it leaves at and the velocity it leaves at being different that matters. The only way it is only the bullet and the wind after 100 that matters is if every bullet leaves at exactly the same velocity and angle. They all leave at different velocities and angles. Tuning your load makes those differences work in your favour instead of against you.
I think short barrels shoot lighter bullets better and longer barrels heavier bullets. 168 match kings great in 24 inch barrel. 125 in 24" suck. 168 in 12.5 suck. The 12.5 shoots the 125 great. When you look at velocity it kind of makes sense. Not too much good happens over 3000 fps.
I am addicted to this podcast, love the info i get from it. 100s of years of collective wisdom and experience shared... thank you Erik for what you are doing for the community
Erik, you are doing the shooting community a lot of good, with scratching open all these golden nuggets for the broader community. Thank you. The Long-family's work and the combination Gordon's GRT add to it is absolute magic. Thank's Chris and RIP Gordon.
OBT is awesome as long as you don't mind tuning quickload. One of the best tools in the box for sure, and indispensible for choosing a powder.
I'm really enjoying the physics of a barrel.. really enjoying this podcast.
I have been a distant (South Africa) follower of Dan Newberry and the Chris Long developments for some time now. Chris was even kind enough to entertain a couple of my emails and to answer these to clear up confusion that I had. It was so awesome to see you feature them, lovely to put faces to the names. Awesome podcast, true leaders in their fields, like you, always give back to help the sport grow. Many thanks Erik.
I wonder who was the south African than Dan was referring to
@@dawielubbe9443Cassie Nienaber?
Never fails to impress me with advanced information , THANK YOU GENTLEMEN
Thanks Erik for posting, especially when it includes individuals that have applied their formal technical/engineering related background towards the enjoyment of improving their hobby and sharing their results. I’ve utilized the OBT concept in the past from Chris’ web page and especially Gordon’s reloading tool to get me in a fps ball park window for my combination of barrel length, case volume to powder ratio, etc... We have so many variables at play from trigger to target but all worth the effort when withnessing that cloverleaf at distance! On Varmint Al’s web page, he has sharred his analysis on barrel harmonics which for me was also a great read. Again thanks for your videos.
Another reason to watch your interviews ! Keep them coming Erik.
Erik, thank you for all you are doing to advance the sport. I am big fan!
I love listening to Chris explain his thoughts and experiences with load development.
He and I must be about the same age. I got my BSEE degree in 1981 but I spent 4 years in the Air Force first. Chris got his graduate degree in 1980.
The modes Chris is talking about is actually called order harmonics. So first order harmonic second order harmonic and so on. You have even and uneven harmonics which can amplify each other .
Well mate... that was a very enjoyable interview. Thank you for putting this together. Much appreciated.
I've been visualizing a "donut", ie a wide spot, moving down the barrel from the explosion and reflecting back. It's not an expansion, it's a contraction. His background in RF gave him the insight to figure out what was happening. Standing waves are a big part of RF transmission. Thank's for doing these videos Eric. Slowly but surely this is starting to make sense.
Such a great podcast, so many new things to consider from it.
Great topic as I've wondered about this over 40yrs.
Great interview and discussion guys. Loved every second of it and learning from you.👍
Thank you for sharing info, I don’t comment on these enough, but again, thank you for all of the information because it helps a lot of shooters
Good ole Matlab. This guy seems to have a very strong grasp of internal ballistics. Great podcast. I like it when we get into the weeds about the subject. Ballistics are such an awesome topic and interesting science. I reckon Ima bout to have to spend a whole lotta time in Quickload and reading a paper on a topic I had no idea existed. I knew about the concept, but I had no idea there was all this extra information.
Chris, thank you for taking the time to speak and share your knowledge with us.
I have been using the OBT model for many years, and I have a lot of faith in it. It works. It requires some work and constant tuning (trueing Quickload), but I enjoy the challenge. I'm not looking for F-class precision...MOA of Coyote is fine with me.
Thanks guys!!!! I always test temp to MV for temperature variation. It’s very necessary to know the correct mv and run it in the ballistics wether in a ballistic computer or in an analog computation. The case volume matters here, the same powder in different size cases will have a different burn rate vs mv per every 1 deg of change. Loving these videos!!!
Awesome interview once again I picked up alot more tools for the tool box
Great info!
Awesome education!
Thank you for the knowledge
Fantastic interview with Chris no doubt. Love these load development videos. Very educational and helpful. Question. What is the proper way to test primers ?
Any shock impulse occurring at the chamber will not only travel forward to the muzzle, but will also travel backwards. The backwards wave will then reflect forwards before the primary forward wave reaches the muzzle. This reflected rearward wave will arrive at the muzzle slightly after the primary forward wave does, and will be out of phase to some degree. The primary forward wave as reflected will travel through the secondary forward wave and the amplitudes will be algebraically summed together. That means the combination could be additive or substractive at the point of intersection. This reflection pattern will continue to repeat itself at reduced amplitudes until the energy is dissipated by molecular friction until it is no longer significant. It is similar to Standing Wave Theory in electronics. Therefore, the effects would be almost completely dissipated by node 2 or 3. So if the bullet does not travel down the barrel at such a speed as to arrive during node 2 or 3. the effect will be dissipated to uselessness. How many 6000 fps bullets do you know of?
Hello Eric. Love every podcast. At the end of this pod cast you mentioned people saying a bullet likes a particular speed. I have been mowing through my last 34 years of experience in loading and shooting and the only thing I can come up with having to do with Bullet liking a particular speed is the proper rpm range that the bullet likes and needs to stay stable not particularly the speed. Anyway keep up the great videos.
This is really cool
I've been looking at GRT, wondering about the effects of burn time & powder efficiency.
I think Gordons reloading tool has a obt calculation, not sure if its related
Grt is using his obt theory
Can I ask a question that I can’t seem to find an answer for?:
In regard to OBT on an AR15, what effect does the gas block/gas tube and flash suppressor have on the OBT chart? Thanks a lot for the great videos!
Wish people would go check out this guy's channel he needs help growing his channel and his health Adventures in machining here on TH-cam ( cortina).
Will you please upload the rest of the podcast to Spotify
Is the axial reaction of the barrel against the bullet following the rifling part of this equation?
Chris says a 70-80 fps change in muzzle velocity for 2 different powders both in tune. Does this mean you have tuned at different OBT nodes (since the MV has changed) or does this mean that you hit the same OBT node even though the muzzle velocities are different. Seems like the latter could possibly occur if a different powder can result in a different acceleration profiles.
Yes you’re right . Different powders can have different muzzle velocities at the same barrel time. Due to different bullet acceleration which is dictated by burn rate and other powder voodoo
An app would take the fun out of it😊
😂😂😂
Get ready to get your feelings hurt. Someone has to make a meme of that phrase
How is OBT affected by barrel material? Stainless vs Chromoly.
35:35 to 38:55 ----pay dirt
I find it interesting that Erik and many others seem to be overlooking something very simple with regard to this idea of “if it shoots at 100 but falls apart at 1000 then it has to be something with the bullet itself that needs to be improved because when it left the gun all was good, as seen by the results at 100.” While there could certainly be aspects of the bullet that need improving this is still a problem to be dealt with in the harmonics phase first. It is not something out of your control or to do with how perfect the bullets are. It is still a harmonics problem.
If you have the hypothetical perfect bullet, with literally zero flaws, but still have a real-world load that has non-zero SD and ES, so each round still varies a little bit in velocity, if you tune everything so you’re getting groups at 100 that are as close to perfect as possible, with as little vertical on paper as possible, external ballistics DICTATES that the groups at 1000 will show more vertical. If it is a group at 100 that only has 0.1 MOA of vertical it WILL NOT have 0.1 MOA at 1000. But this is what I think Erik thinks. And this idea is wrong. If you have a load that shows 0.1 MOA at 100 but shows, let’s say 1 MOA at 1000 just for sake of conversation, i believe Erik is saying the reason that happens has to do with how the characteristics of the bullets are affecting the flight after it has left the gun.
The problem with that idea should be very apparent if you sit down for a minute with a ballistics calculator. With a ballistics calculator we are able to examine the problem with the mythical perfect bullets that all have exactly the same shape, same weight, same perfect points and all other dimensions. We can’t test that accurately in real life because all bullets vary a little. So we will always have to question the results. “Maybe the difference is just because the bullets aren’t perfect.” Yes, that’s true. The bullets always vary a bit. But with a ballistics calculator we can look at the problem with the mythical perfect bullets at our disposal.
Take the actual ES of one of your actual loads and use that to play with the ballistic calculator. If you have a load that averages 2850 fps, and you have an ES of 10, then punch that stuff into the ballistics calculator.
Actually, I’m going to send this reply right now because I’m currently on my phone. I’m going to send and then move to my computer so I can do the ballistics calculator example myself to show the numbers it spits out. Then I’ll reply to myself with those figures in a few minutes here.
I can see what you're saying, very interesting, seems intuitive
Weird, where'd my reply go with the numbers? hehe. Oh, maybe the URL for the ballistics calculator I used got it automatically flagged as spam. I'll try to write it again, and I'll leave the URL out, haha.
ok, I'll try to post this again without the ballistics calculator URL. Seems the first reply may have been automatically flagged as spam, and I'm assuming it was because it contained an URL. You can use any ballistics calculator to see for yourself. I used the JBM Ballistics one on their website, which already contained the bullet I'll mention in a second in its drop down menu for bullet selection. I'll try to remember the example I used and what I said...
So, if I recall, Erik likes or at one point liked to use the Berger 184-grain .284 Hybrid Target bullets, though which bullet we use doesn't really matter. The actual numbers will change, but the fact that there is a difference will still show regardless of which bullet is used. Anyway, we'll go with the Berger 184-grain bullets. And I believe he may have stated that a load he was using at the time got these guys going about 2850 fps. An ES of 20 fps might be pretty typical, so we'll go with that, too.
2850 fps with an ES of 20 will give us rounds moving in the range of 2840 fps and 2860 fps. If we have a perfect 0.0" group at 100 yards with three shots, one at 2840 fps, one at 2850 fps, and one at 2860 fps, what happens out at 1000 yards when it is 0.0" at 100 yards?
Bullet drop at 1000 yards with a perfect 0.0" 100-yard group:
2840 fps: -273.0"
2850 fps: -270.7"
2860 fps: -268.6"
So with 0.0" or 0.0 MOA of vertical at 100 yards we will see 4.4" or 0.42 MOA of vertical out at 1000 yards for those same shots. It MUST show that much vertical at 1000 yards if there is none at 100 yards because of the different launch angles required for the different muzzle velocities to hit the same spot at 100 yards. A shot at 2840 fps will need a slightly larger launch angle than a shot at 2860 fps in order to hit the same spot at 100 yards. And the differing velocities and launch angles dictate that we will see a difference in point of impact out at 1000 yards, and with those speeds and the 100-yard zero that is how much vertical there will be. 0.42 MOA in this case.
Now, how about we look at it from the other side? Let's look at it from the 1000-yard perspective. If we hit a magical 0.0" group at 1000 yards what does it look like back at the 100-yard mark?
Bullet drop at 100 yards with a perfect 0.0" 1000-yard group:
2840 fps: +27.3"
2850 fps: +27.1"
2860 fps: +26.9"
And again, at the opposite target distance we see vertical due to the differing velocities and required differences in launch angles. At this end we see 0.4" or 0.38 MOA of vertical at 100 yards with a perfect 0.0" group at 1000 yards. This is why you cannot get the best results at 1000 yards by tuning the load at 100 yards. A perfect group at 100 yards will have unwanted vertical at 1000 yards because that's just how ballistics works.
You could try to test this in the real world if you have two ShotMarker systems and you set one up at 100 yards and the other at 1000 yards so that you are shooting through both of them at once. You will then have to contend with real world weather conditions, so you will not be able to see exactly the same results as you will get with the ballistics calculator, but you should still be able to see how tuning for 100 yards negatively affects the 1000-yard results, or how tuning for 1000 yards negatively affects the 100-yard results. It is too bad electronic targets for rimfire are so expensive, because you could do a similar test in a tunnel with two electronic targets and eliminate the wind factor. (Last time I looked they were something stupid like $15,000 each!) One at 50 yards and one at 100 yards with a 22 LR bench gun tuned for 50 yards would show the same effect. Tuning so the groups are as small as possible at 50 yards will introduce vertical at 100 yards, and vice versa. That's just how ballistic physics work. And this is why you must tune at competition distance in order to get the best results. If you tune at a different distance you are introducing additional vertical at competition distance.
How can the rifle change the flight of the bullet 100 yards from the barrel? Beyond 100 yards any change in group size can only be the bullet and the wind. I pretty much agree with Erik. However I would not argue that if you could then get the bullet shooting a tighter group at 100 then the bullet may be more stable and therefore shoot better at 1000. But as Erik says once you are getting one hole groups at 100 and larger moa groups at 1000 it can not be the gun.
@@billclifton8400 I suggest you re-read the comment with all the numbers. It doesn’t change what happens after passing 100. What happens at the muzzle determines what happens at 100 and 1000, but as the numbers show, what happens at 100 and 1000 with varying bullet velocities is different at those distances. It has to be different because that’s how ballistics works. It isn’t only the bullet and the wind. It is the angle it leaves at and the velocity it leaves at being different that matters. The only way it is only the bullet and the wind after 100 that matters is if every bullet leaves at exactly the same velocity and angle. They all leave at different velocities and angles. Tuning your load makes those differences work in your favour instead of against you.
Bedding, Bedding, Bedding.......way more important than people think.
I watch your channel you need to get on here
@@chrismartinez8393 your recommendation was enough for me to subscribe to his channel, thanks for that
@@chrismartinez8393 Dear Sir - Contact him - I would do it. Thank you.
Get some.
I think short barrels shoot lighter bullets better and longer barrels heavier bullets. 168 match kings great in 24 inch barrel. 125 in 24" suck. 168 in 12.5 suck. The 12.5 shoots the 125 great. When you look at velocity it kind of makes sense. Not too much good happens over 3000 fps.
1st.