Range Report Spindrift Calculation??

#301
Re: Spindrift Calculation??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NOMAD</div><div class="ubbcode-body">Brown Dog do you even own any rifles? Didnt the gun grabbers take your rights away!!

Wait this is all becoming quite clear now this spin drift data he is posting is for his .22 LR

</div></div>

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I read a book on air rifles once.


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#306
Re: Spindrift Calculation??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">Nothing good, I'm ballistically challenged and have a hard time with numbers, and even letters sometimes. I'm hoping to get better but the words are a little too big for me right now. </div></div>

At last an accurate self assessment. Well done.

Now if you could just take us through your 'laces on a football' theory of (spin)drift one more time
laugh.gif



 
#308
Re: Spindrift Calculation??

Sure, but its not mine, I just read it... and it was a baseball.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">The spinning action created when the pitcher releases the ball is the secret behind the curveball. This spinning causes air to flow differently over the top of the ball than it does under the ball. The top of the ball is spinning directly into air and the bottom of the ball is spinning with the air flow. The air under the ball is flowing faster than air on top of the ball creating less pressure, which forces the ball to move down or curve. This imbalance of force is called the Magnus Effect, named for physicist Gustav Magnus, who discovered in 1852 that a spinning object traveling through liquid is forced to move sideways.

<span style="font-weight: bold">Adding to the air pressure exerted on the ball are the 108 red stitches that hold the cover on the ball. Because they are raised, the stitches increase the amount of friction created as the air passes around the ball and places more air pressure on top of the ball.</span> A well thrown curveball can move as much as 17 inches either way. If you've ever seen a batter jump out of the way of a baseball that ends up crossing over the plate, you've seen a good curveball. </div></div>

http://entertainment.howstuffworks.com/question444.htm
 
#309
Re: Spindrift Calculation??

Not into the name calling and wish that would stop.

I am into learning how I can predict bulet drift based on rotationaly mass and spin speed. I am hoping we switch to how this effects path after 1000 yards since it seems most agree it is there after 1000 yards.

Dean can it be done without a 5000.00 comp?

Brown just posting what I see after many thousands of rounds fired at a 1000 yards. Patternes do develop.

I think if guys would just exchange information and get away from this my dink is bigger we might all have good discussion I know most of you and you are all good guys.
 
#312
Re: Spindrift Calculation??

OK Frank your site I will butt out. I just think the three of you have a beer and would be friends. My apologies for attempting to be peace maker. In person you guys would probably not be so rough on each other or someone would have loose teeth. LOL. I am doing my best to not get into stupid arguments on net these days.

I am out of this thread now. If anyone wishes to share info with me so we can learn more about it please PM. The rest are welcome to come out and shoot with me and see what I have in data books if you like.

 
#314
Re: Spindrift Calculation??

Frank you just have mastered the controlled jerk of your trigger which is automatically compensating for your Spin Drift error dummy!!!
 
#318
Re: Spindrift Calculation??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Captain Kick-Ass</div><div class="ubbcode-body">so what is the final say on spin drift that we all agree on? </div></div>

Now that was funny!!!

 
#319
Re: Spindrift Calculation??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NOMAD</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Captain Kick-Ass</div><div class="ubbcode-body">so what is the final say on spin drift that we all agree on? </div></div>

Now that was funny!!!

</div></div>

Really?

I thought we'd agreed on this:

Phgh1010172.jpg



based on this:

P1010190.jpg

P1010191.jpg

P1010192.jpg

P1010193.jpg

P1010194.jpg

P1010195.jpg



or was it:

I fire lots of bullets and it makes no sense to me



laugh.gif

 
#321
Re: Spindrift Calculation??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Captain Kick-Ass</div><div class="ubbcode-body">I can't find those pages in my Ultimate Sniper book.... what page are you on?</div></div>

Genius... Pure Comic Genius, you are all witness to greatness.
 
#322
Re: Spindrift Calculation??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Captain Kick-Ass</div><div class="ubbcode-body">I can't find those pages in my Ultimate Sniper book.... what page are you on?</div></div>

Genius... Pure Comic Genius, you are all witness to greatness. </div></div>



That was pretty good........
 
#323
Re: Spindrift Calculation??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tactical</div><div class="ubbcode-body">Now brings up a question. Are all bullets and twists equal in drift? I dont believe so. I wish someone had hard data to look at on this.</div></div>

No, all bullets are not equal in spin drift. Those bullets that are longer have more of a profile to show to the air as the nose is held high, and have more surface area to drag air molecules around and induce the spin drift. However, within the family of 155 Scenars and 175 SMKs, these bullets are all so similar in profile that it would be extremely hard to meaure and spin drift differences.
 
#324
Re: Spindrift Calculation??

The Corrected Information from JBM is interesting, a bit high in my opinion but interesting.

Changing the wind from left to right you have a 1.7MOA correction difference as well as a 1 MOA elevation change.

I may have a take a table from there with me Saturday to shoot that Prairie Dog match in Pueblo to see how it jives. Although I am not sure if everything is inputted correctly, too many numbers are default to be sure it was right for my limited mind anyway.
smile.gif
 
#325
Re: Spindrift Calculation??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchAlsup</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tactical</div><div class="ubbcode-body">Now brings up a question. Are all bullets and twists equal in drift? I dont believe so. I wish someone had hard data to look at on this.</div></div>

No, all bullets are not equal in spin drift. Those bullets that are longer have more of a profile to show to the air as the nose is held high, and have more surface area to drag air molecules around and induce the spin drift. However, within the family of 155 Scenars and 175 SMKs, these bullets are all so similar in profile that it would be extremely hard to meaure and spin drift differences. </div></div>


I think we can agree on this.
 
#326
Re: Spindrift Calculation??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">The Corrected Information from JBM is interesting, a bit high in my opinion but interesting.

Changing the wind from left to right you have a 1.7MOA correction difference as well as a 1 MOA elevation change.

I may have a take a table from there with me Saturday to shoot that Prairie Dog match in Pueblo to see how it jives. Although I am not sure if everything is inputted correctly, too many numbers are default to be sure it was right for my limited mind anyway.
smile.gif
</div></div>

JBM also claims that a rifle bullet fired at a downhill angle has less drop than one fired at an uphill angle, with the degree of angle being identical. I believe that is incorrect for small arms shoulder fired weapons and that they are not taking into account all of the variables. Of course an airplane at a high altitude firing down at a step angle would see a difference.
 
#327
Re: Spindrift Calculation??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">The Corrected Information from JBM is interesting, a bit high in my opinion but interesting.

Changing the wind from left to right you have a 1.7MOA correction difference as well as a 1 MOA elevation change.

I may have a take a table from there with me Saturday to shoot that Prairie Dog match in Pueblo to see how it jives. Although I am not sure if everything is inputted correctly, too many numbers are default to be sure it was right for my limited mind anyway.
smile.gif
</div></div>

Bloody Hell, so after all that arguing you're now going to try it?!
crazy.gif
laugh.gif
 
#336
Re: Spindrift Calculation??

So what have we learned, or did we learn anything from all of this?
There are those that could shine a light or three, but they ran out of band-aids long ago, hence the none posting.

Not everyone here is a field guy, one way guy, or top preformer in anything but, the one thing all should understand we can learn from each other most anytime. Everything is not as it always appears,...



 
#338
Re: Spindrift Calculation??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SFC Carpentier jr</div><div class="ubbcode-body"> Some believe that there is spin drift and some do not. </div></div>

yep... spin drift is just like the moon landing, easter bunny, jesus, ect.....
 
#339
Re: Spindrift Calculation??


I think that we all or at least most agree that SD exist it is the amount of it out to 1K that is in great dispute. Brown Dog claims to use .36 Mills with his 308 and 155 grain Scenars. That's a lot of Spin Drift for 1K IMHO
 
#340
Re: Spindrift Calculation??

I'm sure it does exist. Those BR shooters all believe in it and they call wind far better than I do. Their groups are much better as well.

I remember laying down on the rocks...rifle resting on a Buttpack...ranging the echo trgt with mil footballs...making a wind call based off of dust, leaves branches,etc...squeezing the trigger and smacking that steel all the way out to 1000 yards...all day. We all did it.

Interestingly enough it was with a 1-12 .308 bbl and a 173gr Special Ball. I fixed 10X...OMG and only had 4 minutes of wind adjustment...the horror. It must have been a miracle every time we hit anything. a whole pallet...cases and cases of miracles.

I won't even get into the cleaning regime of Breakfree and OTIS...but what about all that copper fouling?

Now I need a bullet with a BC over .55 @ a velocity of over 3000fps, a scope that has everything including lights, a DBM, bi-pod, adj cheek-piece, LRF, wind meter, crazy copper cleaners...I mean the list goes on. What the hell happened. I'm a mess.

Point is...I don't shoot any better now that I know all this new stuff. In fact it probably shortened my life thinking about it all. It was much easier back in the day just laying on the rocks.

All this info has it's place but it's not always necessary.

--KJ
 
#341
Re: Spindrift Calculation??

Alrighty then...I go on a business trip for 48 hours with no Internet service and come back to 34 pages of almost useless information. I was really hoping Frank would lock this thread down or it would have finally run its course. No such luck, but in the end did we learn anything???

Spin drift exists
Different bullet exhibit different spin drift characteristics
Too many variables to be accurately calculated
Some folks shoot where it's dead calm outside with zero wind and have good enough eyesight to see their own bullets spin drift as it goes down range...I still get a giggle out of that one
Some folks need to study ballistics
Some folks are really thick headed and can't accept the actual facts
I believe those are the folks that just like to hear themselves think (online) and are great debaters but don't know when to give up
For those who correct for spin drift...go for it.
For the other 99.999999999999999999999999999999999999% of the long range shooters out there who knowingly or unknowingly factor in any spin drift into your long range windage adjustments keep on truck'n

But please agree to disagree and put this thread out of everyone's misery!
 
#342
Re: Spindrift Calculation??

Here is my contribution, I spent some time in Marine Corps Artillery and the following info is taken out of an old tabular firing table I kept for posterity. If an M198 howitzer is firing a 95 pound projectile at what is considered a max charge the muzzle velocity is expected to be 684 meters per second. This is what is called cold stick data as there is not any other contributing factor for muzzle velocity variation taken into account. To put this into perspective for most shooters that is a 665,000 grain projectile moving out at 2244 feet per second, this is with a charge that would be used to engage something about 10 miles away. The drift correction out of the TFT at 1000m is 0.2 mil which is hardly anything given the weapon system capabilities. I was taught that drift is directly correlated to the time of flight as well as the Quadrant Elevation which is simply the angle that the barrel is at when fired. If the projectile is in the air longer then drift is going to take an effect on the trajectory in a lateral direction, increasing as time of flight increases. In high angle fire the time of flight is very long as the projectile is in an extremely high trajectory, hence the quadrant elevation is high so the drift value is large. Looking at the numbers in the tables show that for the most part drift at low QE values does not seriously affect the projectile in the first 1000m. There should not be much difference between this and what is being discussed as both are still physically the same thing, albeit my example is a larger projectile.
 
#343
Re: Spindrift Calculation??

Come on
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we haven't even got into the effects of low air pressure (high altitude) and air temp changes in relation to SD. And it ain't what you might think... sorry, couldn't help it > All in all, it's good discussion.

Wilshire... your drift in relation to high angle fire is NOT spin drift, it's a different world. With 30 second time of flight, as in naval gunnery, the spin of the EARTH is a common big correction. Naval gunnery corrections in the magnitude of tens of yards to 25+ mile shots. These are very high angle shots of course.

Artillery and naval gun fire typicaly is not supersonic on it's way down the falling branch of the ordinate. Supersonic transition occurs during it's climb to the max ord so the small "Spin Drift" that does occur is well before the max ord as opposed to rifle fire which occurs after max ord.

Back to riding my horses
smile.gif
 
#345
Re: Spindrift Calculation??

Wind deflection, elevation take off angles, are also mathematical formulas,,, and all are affected by air temp, and BP changes. Wind corrections are temp driven, granted not a 308 ranges, unless you're within 10% of transonic range, then yes, those values are affected... not trying to be a nit picker, but the ranges I shoot at 99% of the time are not guess at ranges, nothing is ignored, temps, BPs etc. are corrected for a the 0.5 degree temp values and 0.25 In. Hg. values. Bore temps are monitored very very close.

Later shooters, might be alot of rehash here, but it's a good thing
smile.gif
Most posts die a quiet death, long before any real good discussion gets going, kind of like my an my recently past marriage... whew, that's spooky.
 
#347
Re: Spindrift Calculation??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: toddacguy</div><div class="ubbcode-body">Dude do the math on this how much Douche berry pie do you have to eat before you become a DDDDouche bag? </div></div>

Bitch, you gonna be cooking my douche berry pie and rubbing my feet in the camper this weekend!

The one fucker that has true spin drift set ups on his rifles has only the above to post.

 
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