I don’t even have to look. I don’t care at all whether they go forwards, sideways, or backwards, or how far out they eject. Their VERTICAL path will always follow a parabola based on Earth gravity. You may completely ignore the horizontal component.
1 Like
Actually it was almost a real task in my life.
A machine makes 65 rounds every minute. Bullets weight must be measured on digital scale. How many samples the scale must take? (There was a guess by an old man: 10 sps)
Spoiler: we did not calculate the standard deviation and the uncertainty. Our expert said: the worst case error must be small enough.
1 Like
I hope that didn’t come off flippant. If the casing came out near horizontal or barely rose at all, it might be more difficult to check the physics at this distance. But this one went spinning in a cute little upwards path perfect for a photo op, so we may as well make sure the physics works.
1 Like
Thanks for your calculation. I don’t know much about ejected castings physics and how standard this model is across all guns. Appears that there is some variation in gassing pressures that kick out casting, even among the same model guns depending how it is setup and how worn out it is getting. Does this make much of a difference?
Did shot #9 really damage the rifle? As an excuses to not test fire it as see how it really handles? Maybe it did really get smashed up, no more shots after that. Have not been able to identify any significant damage with the gun images released so far. The crowd reaction from shot #10 was the one that let the crowd know it was game over.
Ok, so you guys are going to add even more uncertainty to the already uncertain approach of using video frames to check a distance we already have? So now we would not only have the uncertainty of the video compression dropping frames, the gas tube math that needs checking, but now also the geometry and physics of flying shells using statistical analysis and probability?
@kwaka before you unleash this monstruosity of a task on @kincses-zsolt and @offtheback , maybe could you send us more of what you got so far regarding your approach to use the distance to check if that sound matches that shell ejection, if I got your approach correctly?
I haven’t seen a lot of guns tossing them upwards this much, but I don’t claim to have paid attention either. And even shot-to-shot they flip out differently.
But none of that matters here. All we have to do is take a video of one casing’s journey into history–one that just happened to be tossed up, and make sure it agrees with gravity and is at least authentic in that respect.
1 Like
No. i am doing it to check the source material that we have to work with. The distance is clear between all the maps. What is not clear is why there is a 5 frame discrepancy between the audio and video track. Maybe it it nothing, an innocent mistake, maybe it is something. As part of an audio analysis it is fitting to ask these kinds of questions.
I have sent TMZ a message outlining this problem. If they send me an email I will let the board know.
1 Like
I want to cite R. Feynman: “You don’t like it, go to another Universe.”
4 Likes
Thank you Kincses, for the inspiring punchline… I’ll be in the kitchen with my measuring tape and some popcorn… I’ll try to measure how high they pop.
2 Likes
That’s the muzzle velocity that works out with the parameters I used. I know it’s rather lower than most ammo and AR-15 type rifle combinations. Everyone is welcome to check my numbers. I found I’d made a pretty big mistake yesterday, and wish someone else had caught it first.
The weird thing is, many of us that are thinking the first 3 shots came from the vent of AGR building 6, while shots 4-8 came from Crooks. If my numbers are right, with a snap-bang time of only 0.213 seconds, that muzzle speed for Crook’s rifle would need to be even slower - around 2570 fps.
As far as your sample values, if the velocity at 150 yards is 85% of muzzle velocity, I’d guess the average velocity is a little less than the arithmetic average of 85% and 100% - say 91% or 92%. It worked out to about 94% for one sample I used.
I should probably round the numbers (or specifically show what I think the upper and lower limits might be) to not give the impression they are more precise than they really are.
Uh oh! Richard Feyman reference!
I mentioned elsewhere I’m a Caltech washout. I’m old enough that Professor Feynman was a professor at Caltech while I was a student (1982-1984). In addition to his normal duties, once a week he would host a session called Phys X, where people would just ask any question they wanted.
A lot of freshmen loved to go to this. I’m sure some kids wanted to ask questions that would make them sound really smart. I only went once, and didn’t ask any questions.
Afterwards, my OTHER best friend (not Tsutomu Shimomura) asked Professor Feynman if he would play the bongos at Phys X some time. Prof Feynman said he didn’t think so. I was standing next to my friend at the time. So I kind of, sort of, met Richard Feynman.
This guy had a real fan base at Caltech, let me tell you.
If you watch the movie “Oppenheimer” you will see Richard Feynman portrayed in a few snippets here and there. He is shown playing the bongos in one scene in Los Alamos at Christmastime. In the scene where they detonate the test bomb he’s the guy behind the car windshield saying the windshield should be enough to protect his eyes. In the Caltech alumni facebook group people were talking about that kind of stuff quite a bit after the movie came out.
Anyway, if you look up Tsutomu Shimomura’s wikipedia page, it will say he studied under Richard Feynman at Caltech. What that means is he went to at least one of those Phys X seminars. I think he also sat in on a few actual grad level physics classes Feynman was teaching, but he didn’t enroll in any of them. Tsutomu lasted a year longer than I did, but didn’t end up graduating from anywhere. He’s smart enough and has good enough connections he’s done pretty well for himself anyway. After all, his dad won a Nobel freaking prize. My dad worked at the post office.
1 Like
Maybe some reloads instead of factory ammo? But at those speeds, you might want to try an online ballistic table for 77 grains ammo (I use Hornady’s calculator). For instance, manufacturer CBC Global has the following values for their 77 grains 5.56x45 ammo:
Ballistic coefficient of 0.362
Distance (m) - m/s - fps
Muzzle - 850 - 2790
100m - 767 - 2541
200m - 689 - 2305
300m - 616 - 2081
Test barrel: 50cm - 19.68inches… (Crooks might have used a shorter barrel, say 16", which would give a little less velocity).
Ah yes, sorry, the 94% you’ve been using is the average, and not the velocity at the target’s distance.
1 Like
How about practically? Guess who just learned how to make GIFs? 
I guess we finally have moving hair afterall. We can see his skin when recoil splits his hair. Or light reflecting due to motion, but still, motion nevertheless. While a casing if flying, his shoulder is moving (just a little, his proned body weight acting against the recoil and all), and a head tilt (this one is easier seen on the video editing software going back and forth with the keys, I must admit)
So I’ve decided to install video editing software afterall. Thanks for the ShotCut info, @kwaka. Please take a look at this image above. Is this similar to what you got on your timeline?
I’ve called my frames as such because I didn’t want my count to start at zero, so I just arbitrarily picked 30 as the frame where I see the casing better, so I counted back and forward, assigning frame numbers. This filters here are stabilize, size, that timecode one and sharpness. The video is a direct download from the TMZ website using 💾 Download and Save TMZ.com videos: Quick & Free, No Installation!. The start of the video is point zero on the timeline.
frame 27 - no visible alteration on shooter
frame 28 - shot and shooter feels recoil - hair ‘enlarges’
frame 29 - casing not visible, but must be ejecting - head tilts
frame 30 - casing is clearly visible
frame 31 - casing is clearly visible - hair splits visible
frame 32 - casing - head going forward
frame 33 - casing
frame 34 - casing
frame 35 - casing
frame 36 - casing seen for the last time
frame 37 - casing obstructed view - no sound of shot yet
frame 38 - shot sound is heard for the first time. has already reached the microphone at this frame.
Another thing, when I switch Google Earth to 2D the distance from shooting place to the trunk of the tree, where the tmz video was recorded from, I get 290 feet… closer, but still no cigar.
4 Likes
ALL
For info, the guy at Peak Tactical has been out to Site and taken accurate GPS readings and heights (above sea level.) He’s putting that into a 3d terrain map (held by others.) Which is going to be accurate so thought you should be aware.
3 Likes
Very good and thanks for the review.
One question is how have you defined the frame that the report is detected? Shot Cut is good for video, Audacity does much better with the audio. Able to slow down and more clearly hear what is in the audio. The time stamps help align up the frames.
Are you using a point where the lady screams ‘get’? In going through the audio I find the report starts in the ‘r’ of where she is screams ‘over’. I was out a couple of frames as well when first using Shot Cut alone to find the exact frame. Using Audacity has better audio refinement to double check this point.
In cutting up TMZ video I start at 4 frames before the shoulder recoil and end when the video get blocked out. Enough to set the scene, not excessive. In aligning all the frames to stabilize the images i used the top point of the glasses as a clear sharp reference point.
With Audacity it will help installing the ffmpeg library to help work with MP4 video files: Video tutorial
1 Like
Done a second gif version of the TMZ video by Michael Difrischia:
1 Like
Hi hazard,
Yeah, they have allready shared the data in a video and it is in agreement with our drawing below. 
2 Likes
Hi daniloraf,
I have been working on the same topic as you. I noticed that TMZ updated their video, just after my post which I was claiming you don’t see any dynamic action from Crooks. He seems like he is taking a nap on the hot roof. See my post from Sunday:
I was curious to see what exactly has changed and made a video compare with the free app: “Video Comparer” and to my surprise it did not give a 100% match, only a 99%? Hmm, that’s strange. I wonder where that 1% is coming from (you guys all know where this is leading too 
)
So I cut the original video which I obtained on Friday August 23 and just kept the beginning with the Logo and then the shooting until shortly after the guy passes in front of the camara. I did the same with “newest” version which is online at TMZ and made a video compare again. Hmm strange, still at 99% match. Where is that 1% coming from?
With VLC media play, you can generate a screen shot from every frame of a video. So I generated frame by frame from both videos and started to compare online with this nice webpage:
This is a very strong tool, because you can compare frame by frame in a very professional way. We don’t need to argue if somebody sees a small casing flying or not. Either you get a perfect match when two frames are equal, or you see the differences. Using the slide bar is also a very nice feature.
So what are my findings? Most of the frames generate a perfect match giving me a black screen, 100% identical, but some frames are very mysterious. First I though it might be a frame mismatch, but the frame has a distortion starting at the neck of crooks. His head was put further to the front. You can see the left side of the frame has a perfect match, the right is offset towards the front. I am speculating now, but did somebody edit this video to add some more dynamic action, simulating the recoil of the riffle? 2 Frames later, there is again a perfect match.
Please have a look at Frame 105 it seems the casing has been enhanced, because nobody was seeing any casings in the prior video.
For those who don’t believe me, I strongly recommend that you quicky (I mean really quickly) go have a look at the following website before the video gets taken down:
There you can still find the older version (last Friday version) of the TMZ video which is easy to download, just by clicking the right mouse button.
Extract the frames one by one with VLC media player and compare it with the official one from the TMZ website.
For those who are lazy, I am adding frame 105 from both videos so that you can compare by yourself with diff checker.
If everybody in this Forum agrees with the above findings, then we caught somebody with the hand in the cookie jar and therefore this video would have to be placed in the red zone, being an unreliable source…
4 Likes
this formula is on its way!
I am finishing the ballistic trajectories I have been working on the past 1.5 weeks and that gives you the “current” muzzle velocity (assuming lab conditions) given the manufacturer’s (or empirical) muzzle velocity and ballistic coefficient…
2 Likes
what about the SWAT officer who took the 9th shot?
I believe it is very likely that he also took the 10th shot…
and both bullet 9 and 10 would not pass near Trump’s microphone…