Long Range 101 Part 76 - G1 vs G7 Drag Functions & Ballistic Coefficients

Рет қаралды 94,282

10 жыл бұрын

In this video Rex will discuss bullet drag, ballistic coefficients, form factor, sectional density, the history of the G1 drag function, G1 VS G7 drag functions, and the effects of dynamic instabilities on bullet drag.
Definitions:
Ballistic Coefficient (B.C.) -- The ratio of The ratio of velocity retardation due to air drag for a particular bullet to that of its larger 'G' Model standard reference projectile due to air drag for a particular bullet to that of its larger 'G' Model standard reference projectile
c=WID^2
c = ballistic coefficient
W = mass of bullet in pounds
I = form factor (determined from a test projectile of the SAME SHAPE)
D = bullet diameter (inches)
Ballistic Coefficient = (Bullet Sectional Density) / (Bullet Form Factor- OF THE SAME SHAPE!!!)
Form Factor: A multiplier which relates the shape of a bullet to the shape of the standard projectile used to prepare the particular ballistic table.
Form Factor (coefficient of retardation) = (C.D. of any bullet) / (C.D. of the Defined 'G' Function Std. Bullet)
Coefficient of Drag (C.D.) = an aerodynamic factor that relates air drag to air density, cross-sectional area, velocity and mass.
Sectional Density: (weight multiplied by its frontal area) can then be used to relate the drag coefficient to different bullet sizes.
Dynamic instability has a tremendous effect on a projectile's trajectory. As the yaw increases, the drag increases, the bullet's velocity is far more retarded. These instabilities are not totally predictable and thus predicting and EXACT firing solution is very difficult.
LIST of Drag Functions and their applications:
G1 Standard model, Flat Based with 2 caliber (blunt) nose ogive
G5 For Moderate (low base) Boat Tails - 7° 30' Tail Taper with 6.19 caliber tangent nose ogive
G6 For flat based "Spire Point" type bullets - 6.09 caliber secant nose ogive
G7 For "VLD" type Boat Tails with long 7.5 degree Tail Taper with 10 caliber tangent nose ogive
GS For round balls - based on measured 9/16" spherical projectiles
RA4 Good for .22 Long Rifle, which works out to be identical to G1 below 1400 fps
GL Old school model used for blunt nosed exposed lead bullets, identical to G1 below 1400 fps
Thanks a bunch for your donations to the Rex Reviews Project! We hope these videos continue to be a great help to you all. We recently updated our computer and software thanks to your help. We should now be able to bring you more videos with less glitches, now available in HD!
All the music in this video was created by TiborasaurusRex, an unsigned artist.
Song Title: Wadi Watir, Magnetic Night
Music and Lyrics by: TiborasaurusRex
Instrumentation and Vocals by: TiborasaurusRex
Recorded by: TiborasaurusRex

Пікірлер: 55

@arnaudn.5675 10 жыл бұрын

My left ear enjoyed this video more

@lindazhou4118 6 жыл бұрын

Nearly thought my right earphone is broken before I saw this comment >

@ShawnScaggs 10 жыл бұрын

Dude, you have the most informative channel on KZfaq for long range shooting! Love it keep up the great work!

@Rubicon1776 10 жыл бұрын

Finally, Sniper 101 is back! Can't wait to get to the calc forms! I've been waiting for the calc forms since the beginning.

@kevinhartley7788 10 жыл бұрын

Hi Rex, I'm a relative beginner at long range shooting and have found your Sniper 101 series to be extremely educational! Thank you so much for the information. You have my utmost admiration and respect! Hopefully, I will soon be in a position to occasionally donate some small financial contributions to your cause, here and there. I truly appreciate the enormous amount of work that you have put into educating the rest of us. I have done just enough long range shooting (up to 1,200 yards with 175gr 308 win) to know that you are for real and that you can "walk the walk" as well as talk the talk! :-) Not wanting to miss anything, I went back and started from the beginning of your series and reviewed each episode. I noticed that in part 32 you were explaining the co-sin function as it pertains to the winds effect on trajectory at extreme ranges. I've never attended college and am unfamiliar with trigonometry but, years ago I accidently discovered how the co-sin function works in real-life and found an extremely easy way to explain it. I would love to discuss this with you. I believe that it would you help explain to your viewers that haven't been exposed to higher math, some of your formulas and make it easier for most people to understand at least that part of it. If you would care to talk, please contact me anytime, day or night, at (904) 360-9515. Thanks once again. You are incredible! Kevin

@willnonya9438 9 жыл бұрын

I really like how you explain things. You break it down into an easy way to understand without sacrificing too much technicality.

@supercomp7078 Жыл бұрын

Best explanation yet on KZfaq, it was driving me nuts on how you could a better bullet with a lower published BC

@vincef5832 3 жыл бұрын

Hoping to see a series of printed(hard cover) books for the Sniper 101 course. It would be a fantastic addition to any shooters library.

@rolfgartmann975 8 жыл бұрын

Thank you very, very much for all the videos you've made. They are very good and show the best practice how to gain knowlege about long range shooting. No other "tutorial" is comparable to this! Good Job. BR from Switzerland

@AllanSegalMD 10 жыл бұрын

Keep em coming, Rex. Great series.

@hawaiivolcanosquad3322 10 жыл бұрын

I really really really like this channel !

@LilChantilly 10 жыл бұрын

It is one of my very favorites too! So educational!

@erklaerbaer01 10 жыл бұрын

hellz to the yes, finally a new episode!!! LOVE IT!

@jerrymont2595 5 жыл бұрын

Fantastic Rex !

@jessicapieper8830 10 жыл бұрын

Another great video Rex! By the way, Bryan Litz's book "Applied Ballistics for Long-Range Shooting" is a good source for G7 BC ballistic data.

@TheCousinDan 4 жыл бұрын

29:55 awesome footage of the projectile

@jordandavis1991 6 жыл бұрын

Congrats, you are the first chanel i have ever subscribed too! love your videos, thank you!

@simonwiltshire7089 7 жыл бұрын

Great stuff!!!! Interestingly changing to G7 from G1 in my ballistic app for my 77smk's gives vastly different answers. The nearest by a mile is G1.

@robwebster3063 10 жыл бұрын

I agree, good info as always. But I have to say, shooting a stuffed animal out of a cannon.....nice touch, too funny. Glad to see Sniper 101 is still coming out. Can't wait until the next video.

@thecheapshot1065 2 жыл бұрын

8 years later and this is still the definitive video series for those of us who want one shot one kill extreme long range

@jacobarnard777 10 жыл бұрын

LOVE your vids. THANK YOU

@MB-kh2gu 8 жыл бұрын

Thanks a bunch for explaining exactly what I needed to know. Your presentation was very understandable for those folks such as myself that are a bit math challenged. Anyhow, I was after a good explanation of drag function and which would be the best to use in my long range calculations. You did a great job....Thanks dude, I am going to subscribe to your channel for sure:)

@theclaymore5150 10 жыл бұрын

Good stuff as always!

@jasonford6317 7 жыл бұрын

Very interesting topic here. You should do a focussed segment or video on Saami Specs to distill all the technical infirmation there. It's a lot but worthwhile ad part of your comprehensive tutorial which is excellent. Maybe it could explore how to read and interpret and apply all that information. I would bet you could make it interesting and digestible.

@PreparingForSHTF 10 жыл бұрын

I don't know about everyone else but I can't wait to download the CalcForms and get to work with them.

@mountainman78629ify 5 жыл бұрын

We deal with this in my line of work. we used a conversion factor to convert gross barrels of petroleum products to net barrels and as far as weight goes being 1 of the factors, water is our standard of 1 API, weighing 8.34 pounds per gallon. Gasoline has a higher API of about 59-60 and weighs about 6.25 pounds per gallon. Obviously the lower the number, the heavier the product meaning we haul less amount in barrels to get the same draft in the barges. negative 12 was really heavy. its like using someones foot as a standard. it doesnt matter how big it is, its just gonna be a starting point

@pcombs70 10 жыл бұрын

thank you thank you thank you.

@dhbroussard89 2 жыл бұрын

So the Form factor is best guess voodoo...that is pretty accurate...i can live with that mathematically....

@TiborasaurusRex 6 жыл бұрын

Our Training Schedule: www.rexdefense.com

@Muddlol 10 жыл бұрын

Sweet!

@nisholger8262 2 жыл бұрын

3:27 the formula should be c = W I / D^2 . Divide through square of diameter instead of multiplying with it.

@imeprezime1285 6 ай бұрын

It's not just typo in the video but also in the description of it. While his videos on ELR shooting are generally good, I noticed some old and incorrect myths are propagated in them. For instance, he suggests that most of the riffle bullets become unstable due to effects of transonic zone. Most actually aren't!

@chrisjames7489 4 ай бұрын

I think it’s important to remember how much the Internet has made information like this available more and more. This video series is a decade old and he does get most things correct. It was really hard to get facts straight back then and he did an overwhelmingly good job considering how much information he covered. It’s obvious he took the time to read tons of field manuals and published data rather than regurgitating somebody else’s info from a video. I would be totally down for him updating/remaking the series.

@deepakgupta9856 8 жыл бұрын

Hello Rex. Just a quick question: since you say that the greater the BC (a ratio), the better, and since it is a fraction, this implies that the reference projectile is superior to all these bullets? Is that correct? Regards,

@TTGLL 10 жыл бұрын

I knew the g7 was a more accurate representation of today's rifle bullets. But thanks for the math class. I digg learning the basis for the formulas so that when applied or compared to the empirical data l get a more accurate representation of the results I can expect before going out in the field. I can't imagine trying to work up a drag function for a stuffed animal all those shapes and how it would be deformed do to the changes in pressure. I know this, it would be a ballistic pig and being low density it would lose energy quick. Terminal ballistics would be negligible. LOL

@TiborasaurusRex 10 жыл бұрын

The asymmetrical profile of stuffed pigs, rabbits and bears require a very strong twist to achieve static stability. The stuffed animals with the best external ballistic performance are the stuffed whales and sharks - the tails moves the center of pressure rearward and helps to stabilize their flight considerably... the challenge is keeping them together at supersonic velocities. Premature fragmentation is an issue.

@TTGLL 10 жыл бұрын

Fin stabilized, plush projectiles. Once again Rex showing us the way to go.

@expertmarksman16 10 жыл бұрын

TiborasaurusRex LMFAO

@pepelapiu2004 7 жыл бұрын

TiborasaurusRex I find this comment rather offensive and racist to stuffed bears everywhere.

@johnlee4249 7 жыл бұрын

Lock & Load and fire for effect on the sharks, save the whales.

@randyeggleston7332 9 жыл бұрын

What's a better choice, the Kestrel Applied Ballistics or the Horus?

@DanaWebb2017 9 жыл бұрын

I was wondering if there is a table like in the sierra's 4th edition page 660 reloading manual of the G1 drag function for the G7 drag function were you can get values of the drag for the test bullet.

@Mrpike69 10 жыл бұрын

yay HD!

@rayknickerbocker8142 9 жыл бұрын

These AP projectiles you keep showing.. where to you get them?

@cody182005 10 жыл бұрын

Great video. Enjoy watching your series. What does it mean in my ballistic program when the G7 value is displayed as "Litz" instead of a number? This comes up in the program ISNIPE when i look at .308 berger 168 gr target hybrids. Program still seems to calculate accurate data just wondering what this means. Thanks

@TiborasaurusRex 10 жыл бұрын

Bryan Litz independently verified and refined many of the published BCs in his research... He also work determining G7 values for many bullets. I am guessing the program you are using is simply inputting Litz's BC data.

@carpmaster87 10 жыл бұрын

Also if you are using the JBM Ballistics calculators or tables the projectiles labeled (blitz) are from his data/book I believe.

@dxdx666 8 жыл бұрын

Where did you find this graph from 9:47 ? How did they determine drag coefficients in real flight for velocities as low as 200-300 ft/s when real bullets never flight so slow. Did they fired it at subsonic muzzle velocities and track with radar or what? Thanks for the answer!

@cottojn 3 жыл бұрын

So what is the difference between G5 (7.5 degree short boat tail) and G7 (VLD, 7.5 degree long boat tail)? I Sierra Gameking and I cant find the G Function information for the bullet. I do know that it is a Boat tail bullet.