Yes. I agree. I looked for the 250 grain that you mentioned but not find any. Please provide a link.
We’re looking for an average velocity of about 2790 fps over 138.3 yards, and I did see that the Hornady 200 grain ELDX came in pretty close at 2761 fps.
Thanks, Greg!
Did you by any chance run some math to reduce the velocity of the cartridges tested with longer barrels, to simulate V if they were fired from a 16" barrel? I’ve been subtracting about 8% from the 24" ones, and 5% from the 20" barrels. If you account for that velocity reduction according to barrel, the candidate list would change, I believe… of note, it would probably add, among others, cartridges ID 124 from Magtech and ID 12 from Hornady, both in 5.56, and both are sold in boxes of 50.
Another thing for us to keep in mind. On J13, would Crooks have used a ballistic calculator on his phone to check windage? I believe from the early days there was something on the news about this, but I can’t remember. That would require having the bullet’s BC, so I’ve been ruling out the cartridges that I couldn’t find a published BC from the manufacturer’s website.
I didn’t use any height measurements. I only staked the podium location so I had a reference point when the drone was in the air. I wasn’t trying to figure out angles, fences, or backtracing at the time. The stake was 4’ high and the drone was hovering behind it for the picture.
OK,
I think we are going to come to an agreement sooner than expected!
I had an alternative way to check the notches positoin and have to admit that you are right, the fence with the notches is exactly offset by one fence to the bullet trajectory. I therefore have to retract this hypothesis and apologies to everyone. I lost a lot of credibility on this one.
Thank you for having gone on site so that we could clarify this topic. So: Notches into the red zone!
Just before we bury this topic, the only explanation about these strange notches being so close to the trajectory could be the following:
@kwaka in this post noticed that the complete Trump rally layout footprint was turned by 3 -5 °mentioning that they turned the layout to get a better position to shoot?
So, could it be that the first position they had, was in line with the notches, but after words having noticed that there is a potential collision with the left bleachers and the fence, they decided to change the layout for a better shooting position? Something we should ask the Trump setup team who helped build up the stage: did they have to suddenly change the layout for unknown reasons?
I did not, so thank you for pointing that out to me. It’s kind of important! I implemented that and was able to come up with a result that looks very promising but differs from your conclusion. I tend to not get things right on my first pass, so let me walk you though the steps I did so we can see if anything needs to be fixed.
I did not use the manufacturer’s ballistic coefficient since I was not able to find a formula to utilize it and did not want to invest time into implementing a full-blown ballistic calculator in software. Instead, I used the Muzzle, 100, 200 and 300 yard velocities to compute a coefficient “k” to be used to estimate the bullet velocity at 460 feet.
This is how I computed k in Matlab:
d_yds = [0, 100, 200, 300]; %yards
distance = d_yds * 3; %feet
velocity = [the four numbers from your table]
log_velocity = log(velocity);
p = polyfit(distance, log_velocity, 1); % Linear fit
% Step 4: Calculate k
slope = p(1); % The slope of the line
k = -1 / slope;And then I used k to compute the velocity at 460 feet, and then used that to calculate the average velocity:
V460 = muzzle_velocity * exp(-459.6 / k);
Vavg = (muzzle_velocity + V460) / 2;I also spent some time taking another look at the crack-boom times for shots 1-8. It has always bothered me that there was such a wide range of times (212 to 221 milliseconds). When I first looked at bullet path offset from the podium microphone, I made a mistake (common theme for me) and did not properly quantify how much the offset affected the crack-boom time. Now that I have my act together, here are the correct numbers. If the shot was off-line in both azimuth and elevation by 2.5 m (8.2 ft), that would be enough to reduce the crack-boom time from 221 ms down to 212 ms. The first three shots had crack-boom times of 221, 217 and 212 ms. So, is it possible that the shooter got off line by 2.5 m? I’m going to go out on a limb here and say “yes”. I think that’s what happened. Except for shot 8 (218 ms) all of the other shots were also that far off-line from the podium mic.
Using the formula for average velocity, the velocity for shot 1 is 2584 fps.
1/(1/1152.2 - 0.221/459.6) = 2583.6So, after adding my average velocity column to your table, I sorted the table by avg. velocity and then placed a velocity filter for 2584 +/- 25 fps, and this is what the result is:
The Varmageddon rounds happen to match the predicted Average Velocity exactly. So, I’m going to go ahead and say those are the ones used for shots 1 - 8.
coppercreekcartridgeco.com product/300wm-250atip/
I tried to send this earlier and it didn’t like the complete link so I broke it up in half.
There are also quite a few 220 rounds that are slightly faster. It might make sense that they use these heavier rounds since they aren’t going for extreme distance.
Wow, that company provides a lot of cartridge options!
I did some searching to see if they had one that would produce an average velocity of 2790 over 138.3 yards, and I came up with this one:
190gr Nosler Long Range Accubond
It has a muzzle velocity of 2890 and, using a ballistic calculator, I see that it has a velocity at 140 yards of 2688. So, that’s an average of 2789, which is amazingly close to the 2790 I was looking for. Therefore, it’s certainly possible that that’s the round that the Secret Service sniper used for Shot 10. Though I’m sure it’s also possible that the Secret Service does their own in-house or contracted hand-loading to spec.
Not to distract or get off-topic, but I just picked this T-shirt up today and think it’s badass. OK…back on topic now. 
(When dictator Ceausescu was executed on Christmas 1989, they did not shoot to his head. So that his face to remain recognizable. I mean, it was reasonable not to blow up TMC’s head.)
Possible, but I would bet mostly for testing/training. When push comes to shove, “nobody ever got fired for buying IBM”, if you know what I mean.
Wow! Totally different from what I expected. All but one are .223rem, and only one was tested with a 16” barrel. Three don’t have the test barrel length and another two don’t have published BCs. This post of yours is very, very enticing (and I mean it).
First, because most of the alternatives, especially your pick, seem very counterintuitive to me, as an AR shooter. It would mean that, assuming the ammo bought on J13 was the one he actually used, Crooks chose to use, on his big day, ammo likely different from his rifle’s chamber, that came in a 50 rounds box, with no BC info for him to use on a ballistic calculator and that was tested with a much longer barrel than his. That would imply he was a very good shot with that ammo, and had been training with it since before he went to the range the day before the shooting (because to use the calculator on j13, he would absolutely need to input a BC, which, in the case for this 55gr FBHP Varmageddon, he would’ve needed to have calculated on his own). Not to mention he would have to be quite bold, because a lighter bullet usually doesn’t group at the target as well as heavier bullets. As a shooter with a lesser math knowledge than you or kincses, I would definitely go for rounds with available BC that I could use on a ballistic calculator such as Hornady’s. Personally, I believe Crooks EITHER went to the range the day before (J12) to check his zero with ammo X, and on J13 he bought ammo Y as a backup of sorts OR on J13 he bought more of the same ammo he had already tested the day before. No respectable shooter would attempt such a critical shot with untested ammo in real life. And do keep in mind he actually was very accurate, considering an ear graze. He knew what he was doing. It would be much more difficult for him to accomplish such a shot with a new-to-him ammo on the first shot. Granted, he could have had a 100y zero, a configuration which would give him a lesser need to memorize so many different holds for given possible distances [with a 100y zero, he puts that dot top of his target’s head and at the very least he hits center mass (check me @sgt-raven )]. So, he either already had experience with the ammo bought on J13, or it was his secondary next best ammo because he used too much of his primary ammo the day before on the range while practicing/zeroing/checking-his-zero. Going with that “nobody ever got fired for buying IBM”, why would Crooks risk a much more difficult shot, when there’s tested real life data with a weapon that matches his exact same rifle characteristics? And yet, the average V doesn’t match? Why would that be?
Second, your post is enticing because you ignored BC to get to k. Shooter’s rely on BC, at least I do. Intrigued, I searched for BC formula + Bryan Litz (the ballistics pope in the shooting world). Two pages struck me hard.
a) Berger bullets, which reads: The reason why the BC of a modern long range bullet changes so much at different velocities is because modern bullets are so different in shape compared to the G1 standard that its BC is based on… - …the BC of a modern long range bullet that’s referenced to the G7 standard is constant for all velocities!
b) DTIC.mil (Defense Technical Information Center), a paper titled “Comparing Advertised Ballistic Coefficients with Independent Measurements”, which reads: “This project compares ballistic coefficients advertised by four well-known bullet companies (Hornady, Nosler, Sierra, and Barnes) with those measured by an independent source (Bryan Litz). G1 and G7 ballistic coefficients were determined using calculations at the JBM Ballistics web site. Many published ballistic coefficients are significantly different from independent measurements, with Nosler’s advertised ballistic coefficients showing the largest overestimates.! “
Third, because k would imply that all cartridges and the J13 scenario would have happened at the same atmospheric conditions (and barrel length, also?). Which is also a problem on my spreadsheet (on both Kincses columns and also on the ones I arrived at using the AI recommended approach). To be fair, I believe mainly Temperature would play a significant role at the 462-feet-give-or-take distance, and I would give little attention to altitude at those 407-408m ASL (see Bryan Litz) or angle-if-equalORminus-5-degrees-at-most (see Improved Rifleman’s Rule).
I agree. When one fires 3 shots in 1.5s, the rifle tends to go up and to the left. Unless you have a good solid hold on the rifle, you would be trying to fight the rifle’s motion.
Nice. Even original manufacturer ammo is subject to a little variation.
As a shooter, I would never pick a 55 grains cartridge for that particular scenario if I had a choice, let alone a cartridge without a published BC so I could use a calculator. And that’s what makes this whole thing interesting. You ran math, which is a powerhouse, obviously, and you came up with this cartridge. And yet I wouldn’t use it. @bigtim and @sgt-raven . What are your thoughts on Crooks using ammo without a published BC for his attempt?
@daniloraf Thank you for the detailed response and for providing the citations. What you say makes a lot of sense, so I’ve been rethinking the analysis and trying to gain a better understanding of the details.
This is how I calculated Vavg
Vavg = d / (d/Vs - B)
where
d = distance, 459.6 feet
Vs = speed of sounds, 1152.2 fps
B = crack boom difference, 0.221 seconds
Vavg = 459.6 / (459.6/1152.2 - 0.221) = 2584 fps
For the distance you used in your spreadsheet (465 feet), Vavg = 2547 fps
So, getting the correct distance is important. In this case, it’s a difference of 37 fps.
In the most current version of my TDOA model, I am using these locations:
shooter = [586767.73 4523528.40 6.52]; % meters East, North, Elevation
Podium = [586726.20 4523394.60 5.66];
norm(shooter-Podium) * yds * 3
ans = 459.6446 feet
You have made an excellent point. Temperature and altitude both affect air density and have a significant impact on velocity. From what I can tell on https://shooterscalculator.com, it looks like manufacturers use this standard for the ballistic measurements they publish:
International Standard Atmosphere
Altitude: Sea Level (0 ft)
Barometric Pressure: 29.92 Hg
Temperature: 59° F
Relative Humidity: 50%
Speed of Sound: 1116 fps
Taking Remington Premier Match 77gr as an example, the standard velocity is 2446 at 140 yards, but using the Butler conditions of 93 F and 1335 ft altitude increases the velocity to 2483 fps. Seeing how significant this is, I will need to redo the velocity calculations I did for your ammo table and reassess my top pick.
I find it implausible Crooks went on the roof with so little ammunition. Whether he fired all 8 or only 3 or 5, all still debatable with good evidence he fired either 8 or 5 (probably not just 3), my educated guess is that he had at least 1 full 30 round magazine.
As to why his shooting stopped, I’d theorize that there was no longer a target and/or he was taking stock of the situation hoping Trump would stand up or be moved and he’d have another opportunity. Or he was finished and beginning his exfiltration. Perhaps alternately he had a weapon malfunction (double feed, failure to load, failure to eject, etc.) that paused/stopped his shooting.
So, a plausible order of events:
Sorry, I phrased the sentence poorly before. I meant to say "And yet, the bullet (and it’s avg V) that was tested with the same characteristics as Crooks’s rifle was not a match against (not within) the calculated range of candidates.
By the way, I went to Hornady’s website to look up info on atmospheric conditions during the tests (I remember one manufacturer had this info when I compiled that ammo data, but can’t remember which one), and I just found more 5.56/.223 cartridges on Hornay’s website. Turns out I was looking at hornadyle.com, and there are different ones on hornady.com. There are 37 in total on hornady.com… I’m sure some will be the same from the first Hornady batch already on the spreadsheet, but… dammit. I’ll try to check it later tonight. Of these 37, 12 are sold in boxes of 50. These 12 are all 55 grains ammo. Of these 12, two are 5.56 and ten are .223 . These could be similar in Velocity as your previous choice of ammo.
I have not specifically searched it out but “50” suggests a bulk box, and “bulk boxes” are generally the cheapest, which 55gr tend to be. Not universally but this comports with my general experiences.
To just stop all this speculation on the ammo used,
just ring up the store and ask them what brand & size packs of 50 round ammo you sell.
When you got that info, ask them which one Crooks could have likely bought,
… strait into home base.
Having caught the first shot on video from body cam BWC2122110, things get really easy.
All you do is watch any video and concentrate on window 3 of building 6 and you would be surpised that everything matches up!
Here is just one example taking Stewarts video, everybody knows the sequence from the time zone T-15 to T+15, but has anybody looked prior and after that? Probably not as much as the shooting part, because there is not much to see except a hourse riding by 
. But let’s take a deeper look and concentrate on window 3 prior and after the shooting and you will be surprised what you can see.
This is what an empty window should look like:
Throughout the whole video, you should be seeing a boring empty window.
However in Stewarts video Window 3 changes by the second!
Take for example T-1Min34 sec:
You can allready see that the window is open a crack and the helper is seen with is head lamp on the lowest dim level. Is this a fatal mistake he made, thinking that his head lamp was off, but in reality it is at the lowest dim level? Luckely for us, because throughout the whole video, you see every mouvement from the helper with a perfect back light contrast, something you would never have seen if his head lamp would have been off.
Here is T-48 sec
What’s that rope or tape doing there?
And T+2Min 56sec
The last time you see window 3 in this video, you can clearly see the two separate windows (upper window and lower window) which is in accordance with our findings how they shot through the open upper window.
For those who want to know more about the upper and lower window of window 3 please have a look here:
Now that the back traced bullet trajectory shows to window 3, is the mosaic starting to show us a picture?
Okay. Well, if you do a version 5 of your spreadsheet I will be happy to have another look. In the meantime, I re-ran my average velocity calculation after incorporating the velocity boost resulting from 93 F and 1335 ft elevation compared to the “standard atmosphere” values, and here is what I found:
So, the top ammo pick that you mentioned a few days ago is right there in the middle of the pack, and pretty close to the 2585 fps average that I was expecting to see. However, the Nosler 55gr round is still also within range.
One issue with the TAP Precision is that Hornady classifies it as a Law Enforcement round. (TAP = Tactical Application Police.) So, I don’t know whether you can typically find that on the shelf at a gun store. I see that “hornadyle.com” is their law enforcement oriented website, and “hornady.com” is their normal consumer website. So, I think it’s probably a useful endeavor to incorporate the 37 cartridges you identified on horandy.com
I sent them an email weeks ago, no reply. News reports say the store will not comment on it (respect for the Comperatore family). Besides, we don’t actually know that the ammo fired on j13 was actually the same one he bought earlier that day.
