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Excellent information. I don't understand how one can justify truing their MV based on a single impact given the reality of dispersion and inherent variance in MV. If you know the shot's actual MV then you still have the downrange dispersion due to other factors, no? So why isn't truing just "chasing your tail"? PS I can't wait for the next video!!

Thank Bryan, very useful information. Its time to ditch in my sky screen and Magneto Speed for a Garmin.

Outstanding Bryan, thank you...

I mount my Magnetospeed off barrel...

I've always just use a stop watch.

Thanks,you answered all my questions.

Hello again, Bryan; I. My "Coning Theory of Bullet Motion" is real and based on rigorous physics. I specialized in orbital mechanics as a physics major at Texas A&M in the early 1960's before going to work on NASA's Apollo Project. In fact, I first extracted the coning motions of the bullet's CG from an output file which you generously supplied about 15 years ago from your own 6-DoF simulator by smoothing (and point-by-point differencing) the CG positions over the Slow Mode (coning rate) Precession period for the first 200 yards of flight for a 30-caliber 168-grain SMK bullet fired at 308 muzzle velocity. Coning Theory papers are on ArXive and (better) on ResearchGate. II. A typical target rifle has its CG located several millimeters below its bore axis, which is the line-of-action for recoil forces. This axial recoil force imparts an upward bending moment at the barrel/receiver (or /recoil lug) joint. This transverse bending moment initiates forward moving transverse shear waves into the steel barrel. The rising limb of the recoil force impulse is shaped like the nearly Gaussian rising limb of the base pressure curve in firing a rifle bullet. Peak base pressure occurs slightly before peak chamber pressure when the rifle bullet has typically moved about 50 mm up the barrel. The propagation rate of these transverse bending waves is about 3200 meters/second in room temperature 4140 chrome-moly barrel steel (a little slower for SS or in a hot barrel). This speed is the square root of the barrel's shear modulus of elasticity divided by its density. These pressure waves reflect back and forth about five times before bullet exit from the barrel. The transverse wave is phase-reversed on each reflection which causes the barrel to set up standing wave bending patterns for each of its several transverse vibration modes. Al Harrall's (VarmintAl) dynamic finite element analyses nicely shows this graphically. The rifle barrel mechanically (algebraically) sums the various vibration modes at each point along its length. I can supply a freely available Excel workbook which calculates all of this with or without point mass muzzle attachments at bullet exit time, together with an explanatory paper. I rely on QuickLOAD interior ballistics program for the base pressure and bullet exit time calculations. Barrel bending at the muzzle definitely occurs before bullet exit. III. I patented an Ultra Low Drag bullet design and placed that US Patent into the public domain. The design feature a bore-riding CNC-turned solid copper bullet with a rear driving band. By using the bore diameter as the bullet's caliber instead of the groove diameter of the rifled barrel, supersonic drag is reduced by approximately 6-percent. A similar drag reduction is achieved by selecting a 3.25-caliber Sears-Haack LD head shape instead of a secant ogive. The base of that nose shape is tangent to the cylindrical shank which aids in eliminating in-bore yaw. Further drag reduction is due to eliminating small supersonic shockwaves caused by any type of surface grooving. Further drag reduction is accomplished by machining the base of the 7-degree boat-tail sharp to minimize the alternate shedding of vortices into the bullet's wake. Laminar flow is maintained in the boundary layer over the whole length of our 338-caliber test bullets. This smooth bullet flies with a 30-percent better form factor at Mach 2.5 than the G7 reference (VLD) projectile. To the point of your discussion here, we found that by base drilling these monolithic copper bullets at 0.42-caliber to a depth most of the way under the rear driving band, we could reliably fire 5-shot strings with low single digit extreme spreads as measured with Oehler chronographs. Copper fouling of barrels was also markedly reduced by eliminating most of the blowby. Think of a modern day Minie ball projectile. David Tubb measured 1.006-second time of flight over his instrumented 1000-yard range with H1000 in his 33XC cartridge. The features of this patented bullet, including base drilling, are freely available for use, but they cannot likely be patented again by others. I appreciate your hard work and thoughtful analysis. James A. Boatright, Retired Physicist and Ballistician Jim@BBLLC.INFO

So here's a series of questions for you Bryan. Why does this SD exist? Is this related simply to a SD in powder loadings in the case, or is it more complicated? Here's a thought experiment. Let's say you could load the powder to exactly the same load every time, with bullets that are gyroscopically the same every time, with exactly the same weight in grains, with the rifle held by mounting hardware that didn't allow it to move. What would the distribution of the impacts be, or would every bullet impact at exactly the same place? This goes to what is causing the distribution to begin with. Is it caused by a randomness in metal grain boundaries and a Monte Carlo process where stress propagates one direction one time, and another direction another time? The image you presented behaves like a Monte Carlo process rather than a deterministically physically similar process. On the other hand, it could be that these boundary conditions (like exactly the same bullet weight, powder weight, center of gravity of the bullet, etc.) are false and this is what is leading to the MC distribution of impacts (in other words, it's the randomness in these parameters that is leading to the SD around a mean). Thoughts? Herschel Smith, PE.

In my experience as a US Distinguished Rifleman I have had best success pouring Slip 2000 Carbon Killer into cork plugged barrel and leaving it alone for about a day. The result is great. I never use JB Bore Paste. It is too aggressive in throat.

Desert Tech just mentioned that stainless barrels that are nitrided last longer than non nitrided. A test comparing barrel wear in nitrided vs non-nitrided stainless barrels in for instance 300NM would be interesting. The only nitrided precision rifle barrels I know of are made in Australia.

Fantastic video! Well organized and thorough. Thanks for taking the time and effort.

You are the first person I have heard say the harmonics occur after the shot. I have long believed that to be true but had no leg to stand on in an argument about it.

The groups were smaller with the Magnetospeed attached.

Wow! This guy is so modest for being the world's preeminent precision rifle expert. I'm not but let's redo the intro anyway. "Hi I'm BRYAN LITZ. When it comes to precision rifles I'm Sir Isaac Newton sans nutjob. You pea brained peasants have the honor and pleasure of listening to me relay the laws of shooting as if God himself was speaking through me so shut up and pay attention."

can you please explain this to all the flatearthers in the back please????

Thank you for your time and sharing your knowledge!!

I teach non-engineers Missiles and part of Missile Defense and I start students off gently with the flat earth approximation. But make it clear that it’s all a lie. In our case the variation of gravity with altitude becomes significant quickly (real not pseudoforce) in addition to all the spherical rotation stuff. But as they’re not engineers I don’t make them do the math…

Good stuff! Thanks for sharing. What parameters do you use to identify that a barrel is "broken in"? Some say a slight jump in velocity. I assume velocity levels unlike continued increase as you point out due to bullet drag and increased barrel pressures.

I use autosol mixed with oil, thin it until it's like whipping cream consistency, you will never use anything else again to clean a rifle barrel.

I think the statement that the coriolis force arises because we fit a Cartesian coordinate system to the surface of a sphere is not quite correct. It is about frame of reference, not errors arising in the coordinate system. If one were to use a spherical coordinate system to derive the equations of motion and use a fixed reference frame, I believe the coriolis force would still appear. If one uses a reference frame that rotates with the surface, then the coriolis force would disappear, and the trajectory of a thrown object (for instance on the merry go round) would again appear as a straight line. This is just my understanding without checking it too deeply, so I could be wrong also.

Your point of impact simulation is fantastic. A really useful teaching tool.

After a good barrel break-in, however you like to do it, maintain accuracy. This means clean, confirm zero with up to 5-30 rounds, and maintain your zero. Keep it simple.

So for the vertical component, is it essentially that the v^2/r radial acceleration either adding to the effective acceleration or removing some?

Pseudoforce is right. The Earth is NOT a rotating sphere. The Earth is FLAT and STATIONARY vide General Relativity. Einstein was right!

thanks for the video, I got started long range shooting after reading your book. Happy to see videos.

There's so much that comes into the calculations bullet weight velocity, which without knowing the velocity, its best guess IMHO, so like i mentioned just think of knowing the math's of the calculation based on all the data of the projectile, velocity barrel twist rate, lands and groves of the barrel, barrel length ,what its made out of, as resistance plays a part as well, then not having the velocity of the projectile, unless the manufacture has those data points, then and maybe then you can make a correction on the scope at long distances shorter distance will not atter and i wonder if the scopes these days will have the correction built into it for ELD shooting. like say anything over 1,000 yards upto 5 mile shooting targets like on u tube uploads with 406 cheytac and .338 and .50 cal weapon systems. Now thats insane distances really, plus your never ever ever going to shoot at those distance's ,they do it to prove it can be done. 👍👍👌👌🦘🦘

To think that back in the day you had to learn this, no portable calculators to work it out, but only when your shooting very long distances, like say 1,000 yards + out to over 2,500 meters. Like the longest kill shot to date by Canadian army sniper in Afghanistan. 👍👍🦘🦘

Does fire cracking happen only near the chamber because that’s where bullet go boom or is there something more to it?

Not generally relevant to rifle fire (except celebratory gunfire), but another effect (strongest at the equator, zero at the poles) is that shots traveling upward are deflected west and shots traveling downward are deflected east.

9:24 It's not so much that the Coriolis goes to zero, it's that the Coriolis forces are in a plane that's perpendicular to the Earth's axis wherever you are, but the earth's surface has different angles to the axis at different lattitudes. What's being called "Coriolis" and "Eötvös" forces are just the surface-parallel and surface-perpendicular components of the actual Coriolis force.

0:50 Actually, once you get into General Relativity, gravity itself turns out to be a pseudo-force.

Great video! :)

Technically gravity ain't a force either. Shooting guns and physics, this is awesome

The flat earthers are choking on their dinner !!!! LOL !!!

Use the same process. A Parker Hale type jag works a little better going back and forth with the JB paste.

The 6.5 is basically a 1 MOA rifle unless you spend a boat load of money trying to make it something it was never intended to be. At 1500 yards the energy loss leaves far less than ethical energy and the inherent accuracy is somewhere in a circle with a diameter of 150 inches… that’s 12.5 feet… making it useless from a reliability standpoint.

Thank you.

Thank You and a Happy New Year.

Hey cool. I was asked by a friend years ago about this for target rifle shooting. That's up to 1000m. So I wrote a spreadsheet with the variables, target distance, azimuth, latitude, muzzle velocity, terminal velocity and perhaps one or two I can't remember. Was a fun exercise. I seem to have lost the spreadsheet though. :( The pseudo forces you refer to is Earth moving to goal posts after you pull the trigger. So not fair. At the end of the day, my friend shooting open sights need not be concerned. I wonder at what range with scope it does start to be worth considering though. I used to be a shooter but over 50 years ago. I did a bit of bench rest target shooting. Smallest grouping was the aim then.

Pseudo forces lol AKA you, like everyone that tries to explain this, have zero real understanding of whats going on, but you know how to do some calculations that make your long range shots more accurate.

Weird how people were making longrange shots before they knew about "Coriolis effect". And doing so in every direction from their position.

I have started cleaning brand new, lower cost rifle barrels (ie basic rifle from the store) with JB paste before doing any shooting. I believe this helps speed the "break in" process and gets the barrel "conditioned" with as little ammo wasted as possible ;)

If I'm shooting due east, or due west, the Coriolis effect should be zero, as the projectile isn't crossing any latitudes during it's flight. In other words, the target and the shooter are moving at the same lateral velocity (zero, when facing due east or west), so there's no lateral delta-V. Great. You covered that. But as you shoot north and south of the equator, from the equator, the projectile is now moving through latitudes where there *IS* delta-V. Shouldn't there be a Coriolis effect at those angles? At 30° Latitude, the Coriolis should be nearly zero, as you are shooting due East and due West (or an angle close to it, as you're still acounting for Eötvös), as the latitudes the projectile is passing through on the way to the target are only at a minimally different velocity than the shooter. Am I missing something?

😂

Instructions unclear ; bullet went all the way around and almost hit me. 😮 😂🤣🤣🤣

Really nice explanations. I teach atmosphere/ocean dynamics and have to spend a fair amount of time on this stuff. The math is one thing (tensors!), but coming up with good, consistent physical explanations for these effects in a spherical geometry is challenging.

Your full of crap, go to any sniper forum! We never compensate for earth rotation! I also have an email from the world record holder for the longest shot of 4.4 miles claiming no compensation for rotation.you ever been in combat, we don't sit around with a calculator figuring corolis. Even if your right the earth is spinning at 1500 feet per second, you could Cath anything moving left to right that fast

For those interested, this is why we usually launch rockets to the east when we want to get them in orbit. Takes less fuel to reach orbital velocities.

Greetings from south Texas! Latitude 27 degrees. Great explanation very useful. All the best

Can't wait to see some flerfers show up. Ought to be entertaining. Nice presentation.