Rotation of the Earth?

[rifleman1981]

Re: Rotation of the Earth?

so, does this mean that all of us who actually hit targets at 1000+ yards and don't take into consideration spin drift and all the other variables are just repitiously lucky? what happened to actually taking your equipment out to the field and actually spending quality range time learning the spin drift, elevation come ups, and all the other things that a computer aided ballistics device might not be able to compensate for because of margin of err and the fact that each rifle is going to perform differently, and that there are some things that can't be forsaken like knowing your equipment well enough to calculate for them by experience rather than relying on a computer instead of good solid performance data.

 

[MontanaMarine]

Re: Rotation of the Earth?

Ya know what Frank, given the nature of this exchange, I'm not even going to entertain your queries. You're position is clear.

I'll just leave it at that.

 

[MontanaMarine]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: rifleman1981</div><div class="ubbcode-body">so, does this mean that all of us who actually hit targets at 1000+ yards and don't take into consideration spin drift and all the other variables are just repitiously lucky? ... </div></div>

No, I'm not suggesting that at all.

Hell I don't have computers, and do fair to middling past 1K with a 308 and 30-06.

 

[Lowlight]

Re: Rotation of the Earth?

I have a 208 @ 2870fps going subsonic well before 2000 yards using a DA of 6000 which also brings the Max Ord at 1375 down to 49 ft, so like I said data, less that reliable.

Add in altitude, angle, you can bring it up, but then that skews the numbers. If that was really the range or what you thought to be the range, cause I see about 108moa for that shot.

Again, how much practice you guys getting on a man size target moving because that is what he will be doing?

 

[Lowlight]

Re: Rotation of the Earth?

Of course you won't entertain my queries, because you're not gonna baffle me with bullshit.

 

[Lowlight]

Re: Rotation of the Earth?

One question maybe you will answer what was the measured wind speed?

 

[lovetsx]

Re: Rotation of the Earth?

You go LL! This is why I love SH!

 

[Lowlight]

Re: Rotation of the Earth?

Reason I ask about the wind because here, we can measure 8 mph on the ground and as much as 18 mph on the second deck of the tower, as you move off the ground wind speed increases dramactically, which you never read about with these ELR claims.

So what wind speed number are you figuring with your max ord, the ground speed or are you doubling it? Maybe even tripling it? I would think could account for a lot.

I know here at sea level on the flat deck if I am shooting a grand I add about 4 mph to my wind reading to account for the height, but that is me. And I tend to hit pretty well with short rifles at 1000 yards. Although not like I haven't shot farther, my 7wsm has been to 1997, with a crowd.

 

[MontanaMarine]

Re: Rotation of the Earth?

jrob was using a 30.5 mil correction, so the horizontal distance would have been less than the lased distance of 2296 yards, via PLRF-10. No surprise there as we were shooting up the hill, I couldn't tell you the precise angle.

jrob gave some more details/pics here, if you're genuinely interested,

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2013631&page=1

For S&G, here's my calc, zero set at 2300, to get max ord info of 1025 inches, or 85.4 ft. Temp 75F, pressure 25.60 Hg, humidity 25%

<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>
-------------------------------------------------------------------------------------
Range Velo Time of Energy Path Deflection Total Sight correction Target
city flight to at crosswind drop for setting new lead
LOS of 10.0 Mph zero range 33 fps
-------------------------------------------------------------------------------------
·Yards fps s ft.lbs. in. in. MOA in. Mils MOA yds ·
-------------------------------------------------------------------------------------
| 0 2870 0.0000 3804 -2.0 0.0 ----- 0.0 ------ ----- 0.00
| 200 2634 0.2191 3204 +221.6 1.8 0.84 9.0 -30.7 -105.77 2.40
| 400 2410 0.4559 2682 +425.3 6.7 1.59 37.9 -29.5 -101.50 4.99
| 600 2197 0.7177 2229 +604.6 15.9 2.54 91.1 -28.0 -96.19 7.85
| 800 1995 1.0023 1837 +756.0 29.2 3.49 172.4 -26.2 -90.20 10.96
| 1000 1804 1.3194 1503 +871.3 48.2 4.61 289.6 -24.2 -83.17 14.43
| 1200 1629 1.6729 1225 +941.8 73.7 5.86 451.7 -21.8 -74.91 18.29
M 1370 1490 1.9974 1025 +963.5 99.5 6.93 627.7 -19.5 -67.12 21.84
| 1400 1467 2.0579 994 +962.7 104.6 7.14 663.4 -19.1 -65.63 22.51
| 1600 1327 2.4899 813 +913.8 143.9 8.59 944.9 -15.8 -54.51 27.23
| 1800 1208 2.9639 674 +784.6 190.5 10.11 1306.6 -12.1 -41.60 32.41
| 2000 1116 3.4813 575 +556.4 244.8 11.69 1767.5 -7.7 -26.54 38.07
| 2200 1047 4.0371 506 +215.7 305.8 13.27 2340.8 -2.7 -9.35 44.15
X 2300 1018 4.3277 479 0.0 338.5 14.06 2672.7 0.0 0.00 47.33

</pre></div></div>

Same calc , but zero set at 100 yards,
<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>
-------------------------------------------------------------------------------------
Range Velo Time of Energy Path Deflection Total Sight correction Target
city flight to at crosswind drop for setting new lead
LOS of 10.0 Mph zero range 33 fps
-------------------------------------------------------------------------------------
·Yards fps s ft.lbs. in. in. MOA in. Mils MOA yds ·
-------------------------------------------------------------------------------------
| 0 2870 0.0000 3804 -2.0 0.0 ----- 0.0 ------ ----- 0.00
M 94 2758 0.1007 3512 0.0 0.4 0.45 1.9 0.0 -0.01 1.10
X 100 2751 0.1073 3494 0.0 0.5 0.47 2.2 0.0 0.00 1.17
| 200 2634 0.2191 3204 -2.7 1.8 0.84 9.0 +0.4 +1.27 2.40
P 206 2627 0.2260 3188 -3.0 1.9 0.87 9.6 +0.4 +1.38 2.47
| 400 2410 0.4559 2682 -23.2 6.7 1.59 37.9 +1.6 +5.54 4.99
| 600 2197 0.7177 2229 -68.1 15.9 2.54 91.1 +3.2 +10.85 7.85
| 800 1995 1.0023 1837 -141.1 29.2 3.49 172.4 +4.9 +16.84 10.96
| 1000 1804 1.3194 1503 -250.0 48.2 4.61 289.6 +6.9 +23.87 14.43
| 1200 1629 1.6729 1225 -403.7 73.7 5.86 451.7 +9.3 +32.13 18.29
| 1400 1467 2.0579 994 -607.2 104.6 7.14 663.4 +12.0 +41.41 22.51
| 1600 1327 2.4899 813 -880.3 143.9 8.59 944.9 +15.3 +52.53 27.23
| 1800 1208 2.9639 674 -1233.7 190.5 10.11 1306.6 +19.0 +65.44 32.41
| 2000 1116 3.4813 575 -1686.2 244.8 11.69 1767.5 +23.4 +80.50 38.07
| 2200 1047 4.0371 506 -2251.2 305.8 13.27 2340.8 +28.4 +97.69 44.15
| 2300 1018 4.3277 479 -2579.0 338.5 14.06 2672.7 +31.1 +107.04 47.33

</pre></div></div>

Calc'd correction of 31.1 mils, applied was 30.5 mils, and hits were a tad short. Yes the bullet would have been subsonic.

 

[kraigWY]

Re: Rotation of the Earth?

Thats it, I'm gonna fire up my computer, take my slide rule, and Bryan Liz' book, and I'm going to a Garand Match. See how much better I can shoot at a 200 yard Vintage Rifle Shoot.

Got it figured now.

 

[MontanaMarine]

Re: Rotation of the Earth?

No bullshit here, Frank. I'm very comfortable it relating what I have firsthand experience with.

 

[MontanaMarine]

Re: Rotation of the Earth?

As for wind speed, Broz took a reading at the FP, it was probably around 5 mph or so. Considering we were shooting up a gulch, the winds had to very inconsistent along the way. I don't recall exactly what the wind correction was that jrob applied, but I know it wasn't a whole bunch.

 

[Lowlight]

Re: Rotation of the Earth?

Ha, you said he hit consistently and he missed, you guys were shooting rocks, and call that verifiable.

Not to mention, running the numbers in Ballistics I get different data.

Calling people out about precise numbers, the need to calculate all calculable variables, but you don't know the angle shot?

Data reliability again, suspect. As written , I won't comment on the shooters form, but I would like an audition tape before I take a trip.

 

[DaveV]

Re: Rotation of the Earth?

Yeah, but you don't clean your rifle very often. So that changes all the math

 

[MontanaMarine]

Re: Rotation of the Earth?

I haven't called anyone out on anything. I've only offered my opinion.

Rocks, steel, paper. An aiming point is an aiming point.

I do this for recreation and personal satisfaction. Not training anybody to go in harm's way.

I don't even own an ACI.

 

[MontanaMarine]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">...I would like an audition tape before I take a trip. </div></div>

Like in one hand, and shit in the other....see which one fills up faster.

 

[Lowlight]

Re: Rotation of the Earth?

Guessed the muzzle velocity, held the reticle because you ran out of elevation, no wind hold and no angle information, but offering up a 1moa sized group 300 yards into the subsonic range. So easy a caveman can do it.

Do I have it about right,

maybe the earth spinning brought the target closer helping you out.

 

[Broz]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">Guessed the muzzle velocity, held the reticle because you ran out of elevation, no wind hold and no angle information, but offering up a 1moa sized group 300 yards into the subsonic range. So easy a caveman can do it.

Do I have it about right,

maybe the earth spinning brought the target closer helping you out. </div></div>

LL, I can add some of the data to the best of my memory, not to argue but to add data since I was there and observed the impacts. I only offer this because I was there and it did happen like this. I am in no way saying it is repeatable.
My first round cold bore was dead on for elevation and 1 moa left. I missed with my wind calc. 2nd round was dead hit into point of aim center mass at 1762 yards. We started at 1 mile that day (1762 actually) and worked back.

We were basically done with our practice and jrob wanted to engage at a very long distance just to see what would happen. I ranged the target (rock) in the open so we could see the hits with a Vectronix PLFR10. 2296 yards. Wind per my kestrel was 4~6 mph. Angle of the shot viewed from my rifle as per my Nightforce ACI was 0~2 degrees. The point of aim was higher than us but the distance was so far that the angle was not really detectable on the NF ACI due to the thickness of the needle. I called it zero. Observing through my 8~32x56 NXS with NPR2 reticle I witnessed the hits fall into aproxamatly a 4 ft area. Measuring with my reticle this was with in 1 moa.

This was only done one time as far as what I witnessed. Again, I am in no way implying it is repeatable or consistant. But it did happen.

Jeff

 

[MontanaMarine]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">Guessed the muzzle velocity, held the reticle because you ran out of elevation, no wind hold and no angle information, but offering up a 1moa sized group 300 yards into the subsonic range. So easy a caveman can do it.

Do I have it about right,

maybe the earth spinning brought the target closer helping you out. </div></div>



Not my load, jrob said it was mv 2870, at any rate it made it out there, very close to the calculated correction.

Yes, we used the Vortex Razor's MRAD reticle to hold some elevation after maxing out the erector.

No wind hold (as I recall).

There's your angle data (thanks Broz), 1-2 degrees.

Yes, about 300 yards into the transonic/subsonic area would seem about right. But that is based on a calculation. No way for us to have verified retained velocity.

It's not a matter of easy or hard, we just doped it to the best we could, and gave it a whirl.

Rotation? Couldn't say, I only offered my opinions and some speculation on the subject. But FWIW, we were shooting pretty much from south to north.

 

[gugubica]

Re: Rotation of the Earth?

It boils down to this...

Does it technically exist? Yes

Is it enough to worry about? Fuck no. There are so many other variables that have a huge effect and can cover up earth rotation that the chaos theory comes into effect.

To many things to worry about to dwell on this shit.

 

[Lowlight]

Re: Rotation of the Earth?

So what you are saying is, 1 MOA group with no accounting for the SD or the Earth's rotation and you hit within 1 MOA of the target on your first round...

Impressive, as well you calculated the wind at the shooter between 4 and 6 MPH and that held within 1 MOA across 2300 yards with a Max ord of 85ft so the deviation was 1 MOA left of center.

Well my hat is off to you, you guys are spot on.

 

[High Binder]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Augustis</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Shot In The Dark</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body">But not at the Equator.

</div></div>

If you cross the equator your bullet spins backwards. </div></div>

Not exactly, </div></div>

I thought it would be obvious that that was a joke.

 

[jrob300]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">So what you are saying is, 1 MOA group with no accounting for the SD or the Earth's rotation and you hit within 1 MOA of the target on your first round...

Impressive, as well you calculated the wind at the shooter between 4 and 6 MPH and that held within 1 MOA across 2300 yards with a Max ord of 85ft so the deviation was 1 MOA left of center.

Well my hat is off to you, you guys are spot on. </div></div>

LL,

I was the shooter in this scenario. Actually, it was my second shot. I forgot to hold over on the first.

I was as surprised as anyone that the first round I correctly held was that close to the intended target with a zero wind hold. We were curious about just how far a 300wm could hit consistently. This was NOT a test of a bunch of really complicated formulas or a proof of there validity. Just 3 guys out having fun together. Who just happened to have a PLRF10 available.

My intention, because we really had NO idea what the wind was really doing from station to target, was to put a round downrange and walk them in.

My desire is to become more proficient at ELR 1st round hits, but I'm painfully aware of the factors involved that weigh against me. You can call it a fad, and it might lose it's draw over time, but for now, it's challenging and fun.

I do like Augustis' quote in this regard. "The more we practice, the luckier we get".

This will make you laugh even harder. The load I shot that day has never even been chrono'd. All my field data and JBM were run for the 2870 load and I was shooting between .5 and 1 mil over that data depending on range. My best estimate (I still haven't run them through a chrono) is 2900 fps. I had never intended to shoot that load, just got my ammo boxes mixed up and figured it out when everything was shooting high.

John

 

[Broz]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">So what you are saying is, 1 MOA group with no accounting for the SD or the Earth's rotation and you hit within 1 MOA of the target on your first round...

Impressive, as well you calculated the wind at the shooter between 4 and 6 MPH and that held within 1 MOA across 2300 yards with a Max ord of 85ft so the deviation was 1 MOA left of center.

Well my hat is off to you, you guys are spot on. </div></div>

LL, I think it is safe to say since we were shooting across a gulch we probably had several winds. All that was measured was the wind at the FP. I am pretty sure, (usually in this country) that there was an updraft the last 3 to 500 yards and probably an oposite wind at the target than at the gun coming down the gulch. My point is, as I stated earlier, I am sure Coriolis and SD have an affect, but the wind or lack of being able to know exactly what the wind is doing at the precise time of fire, can easily over ride and hide the coriolis and in some cases even the spindrift. I do enter SD in my calcs, but, I have not been able to accuratly or repeatedly confirm the effect of coriolis. What this day shooting and these shots at extended range tell me is. The 208 A-max from a 300 WM has some posible potential and needs to be tested more. I don't regularly shoot at 2300 yards, but shots at a mile are becoming more frequent.

Jeff

 

[kraigWY]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> "The more we practice, the luckier we get".</div></div>

I can relate to that. Years ago, in the mid 70s, about the time I started High Power, I was a weapons Sgt in a NG SF Company (no, I'm not flash qualified).

We had 48 LAWs were were suppose to train one of the Eskimo NG companies. Problem being, the weather kept them home. If you know the military you know its easier to get ammo then turn it in, so we desided to shoot it, Six of us including the Tm Cmdr.

Being a cocky new HP shooter, I figured all I had to do was hold off a bit for wind, add a bit for elivation, I could hit a old APC 460 years (measured) away.

I picked a aiming spot and Wam, I hit the track, fired four more using the same hold, hitting each time, then quit while I was ahead.

To this day that old Tm Ldr thinks I'm the best anti tank gunner to come down the pike. Doubt I could ever do that again.

 

[Niles Coyote]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kraigWY</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> "The more we practice, the luckier we get".</div></div>

I could hit a old APC 460 years (measured) away. </div></div>

Wow, I know they had been around awhile but I had no idea APC's dated back that far. What equation did you use to launch back into time and did you account for stellar drift?

Sorry couldn’t resist…

 

[E3C3H3O3]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jer</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mram10</div><div class="ubbcode-body">Since the earth rotates at 1038mph (depending on latitude)it obviouslly has an effect at long ranges. Is there any software that takes into account Lat/long and also direction of fire since it seems it would change POI if you shoot north/south (90deg from rotation) vs east/west (parallel to rotation)?

</div></div>

You played the Call of Duty 4:Modern Warfare level 'One shot, one kill' in the single player campaign... didn't ya? </div></div>


Now thats funny

 

[Augustis]

Re: Rotation of the Earth?

First off - To the other members of Sniper Hide:

I am truly sorry to everyone that was/has been drug through the mud as a result of my post regarding this issue. I sincerely thank those that stepped up with your support, or defended my thoughts & our accomplishments in this area.

I am absolutely blown away at the direction this thread has taken, instead of responding with the same form of general platitudes that have already been raised with more of the same - I will make every attempt to stay on track & respond in a professional manner that has, or should be expected of us in a manner that would not further degrade this thread any further.

I must, in some way have the wrong impression about shooting related discussion forums being a means to share information, discuss various aspects related shooting, or to potentially add to the wealth of knowledge that can, or should be shared to attempt to advance the success of marksmen, that potentially sets one, or what I once thought set this forum above the rest....

LL, I am aware that I am a guest in your house, & as such I have for the most part ALWAYS been respectful of others here as a guest.

For the record, IMHO, respect is something that is earned and should not be taken for granted, or regarded as trivial, if one man should find another worthy of his respect, it should be revered as an honor! I have to say, this was totally uncalled for, & has diminished my regard for this forum, which I have called home for many years now.

With that said, it was never my intent to start such a debate (Shit Storm) that would result in personal attacks of certain members of this site, simply because their views, methods, ideas, or information differs from the Admin. of this forum.

I have always held the opinion, or belief, One size does not fit all, in every instance. In the course of "discussion only", I broached the subject of spin drift & coriolis deflection, & added the disclaimer "to each their own", which should have suggested to a reasonable individual, take it for what it is worth to you, or to potentially pursue this avenue, for those that would entertain this means - or method which I feel confident could lead to better down range success engaging targets at extended distances based off of my personal experience in this area. As we all know, the greater the distance, only serves to amplify ballistic errors. This is what ultimately led me down this path of ELR unknown distance shooting almost 8 years ago.

LL
You have stated to the effect "Its a Fad" - your opinion - your own words...

Please review the following & I would strongly suggest that you secure these documents in their entirety for your own personal review:

"The Original HTI Concept: November 1989"
"HTI" - Hard Target Interdiction

ALSO:

"5000 Meter Sniper Rifle Concept"
Proposal - R&D on Long Range Sniper Weapons
Los Alamos National Laboratory MEE-3

Sample of content:
"Recent events have shown that the probability is high that treaties will be signed in the near future leading to a reduction of nuclear weapons. This will lead to more dependence on conventional weapons. In the future world of terrorists and limited war, the role of the Sniper will become increasingly important. The ability to selectively injure or kill at extreme ranges with little risk to one's own personnel can be a very powerful weapon on the battlefield as well as in an anti-terrorist role"

The document further goes on to say:

"In Summary, what is proposed is a systems approach using state-of-art computer analysis to determine the best practical combination of the above items needed to achieve the desired goal. Then the various components of the system must be developed and integrated into a complete system. All of these goals are well within the current state of art.

Any doubts as to the effectiveness of such a weapon should be removed by trying to imagine the impossibility of trying to protect a VIP from assassination by someone armed with such a weapon. Think of having to maintain a 5000m perimeter around a military installation. Wouldn't you rather have the enemy worrying about such things instead?"

This DOD proposal has been driving advancements in technology for almost two (2) decade now!!

Industry & DOD has spent MILLIONS of dollars in the advancement of weapon systems, bullet technology - including high BC, CNC Turned Bullets, as well as integrated ranging, Env. sensors into computer technology to determine POI corrections for such weapon systems...or account for ballistic errors at HTI ELR engagement distances.

The factors that I have attempted to covey into my previous post are factors that are considered, by greater authorities than myself, to be integrated into the firing solutions of such weapon systems past, & currently under development by industry in conjunction with input from the DOD, not something I have conjured up to explain engagement failures on my, or my partner Joe's ability to effectively engage targets at extended distances.

To the contrary, Last year, entrance into the "one mile club" OMC of Wyoming, at the 2009 International Tactical Riflemen's Championship - We successfully engaged a 11" x 16" target first round at a distance of 1800 yards. We were informed by the Admin. of that event, along with everyone in attendance at the shooters meeting, we were the first team to effectively engage this target with a single round fired, & only the second team to effectively do so with a .50 BMG - heavy rifle platform.

That day I fired a total of 4 rounds. One each, at a distance of 500, 750, 1200 & 1800 yards without a single miss on a target.

This year, at the same event, without a spotter & including a 400 yard range error I managed to hit a human size target 3rd & 4th round at a distance of 2200 yards.

2.5 MOA Left correction for SD & CD - my wind estimate was 9 MPH, push from right to left - full value. The second round impact I observed in my scope was dead center @ 6 OC low - measured the impact to center of target, raised elevation and it was mine - two consecutive.

The Admin, knowing I was hunting for their 1800 yard target again this year, I suspect, removed them from the range altogether, & with that I assumed the target I was engaging was in fact the 1800 yard KD buff that I had observed the previous year. I was later informed that was not the case - but to their surprise the target was effectively engaged! Had it been a vehicle, a hard target, I would have been all over it on the third round, most likely before the target would have had the ability to become mobile - We preach, in wind - shoot fast after the initial shot on a follow up, before the condition changes - period end of conversation as far as I am concerned.

Since you are interested in numbers - The engagement distance Shane (Montana Marine) indicated my "associate" made, was a distance of 2950 yards - 3 consecutive - first, second & third. This was witnessed by at leased 12 individuals, none of which with any vested interest in our success, or failure either way. Further, several members of Sniper Hide were present to witness this event. Maybe some of them will come forward if not overly concerned about any potential present, or future reprisals from this forum Admin.

We do not care what everyone thinks personally, the only factor that matters to us is to continually improve our effectiveness & ability.

Ultimately confidence in our secondary function calculations is gained by our success, & proven when the bullets hit the mark. Can we do it every time, under every conceivable field condition, first round - of course the answer is NO. But I believe it is fair to ask you this, can you hit your intended target, say from 1000 to 1500 yards, every single time, & under every conceivable field condition??

What we have observed & preach, "the harder you work, the luckier you get"- are we just lucky, we think not...

I am on uncertain ground here-

Lets start with that to see if my post gets deleted, or this results in my being banned from your site??

If given the opportunity, I will most certainly respond to some of your questions, you raised in your earlier posts when time permits me to do so.

Regards, Aug ><>

 

[Brutas]

Re: Rotation of the Earth?

NBRSA 1000 YD Records 1.473 5 shot group.

http://nbrsa.org/node/65#attachments

Benchrest shooters are well known to be anal-retentive accuracy fanatics that spend tens of thousands annually on competition shooting. I have never heard of anyone that has won anything even mention coriolis effect. If it would improve there group size even .001 they would have 5 different methods for calculating and compensating for it.

 

[jrob300]

Re: Rotation of the Earth?

I must echo Augustis' comments about the direction this thread has gone. I was very surprised to see a rational conversation about concepts that may or may not affect our ability to engage a target at extreme distance, degrade into a discussion not unlike those in the Dark Ages concerning whether or not the earth was flat. The good news is that so far, to the best of my knowledge, no one has been put to death for their beliefs in this arena.

I was there when Augustis' friend put 3 rds. on a rock (yes, a rock) at 2950 yds. I watched him do the calculations ahead of time and then put the first round cold bore right where he intended.

LL, you make some compelling practical arguments for your views. My issue is not necessarily with the "what" but the "how". You probably don't see it this way, but my personal opinion after reading this entire thread in context is that you personally attacked myself, friends I shoot with and a whole community of shooters present and future that will read your words. You repeatedly, with derision, called into question statements and data with little or no benefit of the doubt.

Instead of being encouraging about pushing the envelope, trying new things and actually learning for ourselves, you pretty much insinuated that we either really had no idea what we were doing or we were lying outright.

We may have been just been three guys shooting rocks for fun, but each one of us takes our shooting very seriously and we prepare our rifles, our ammo, our data and our own self-discipline with equal attention.

I may not have known *exactly* where that first round was going to hit, but the fact that it hit centermass/ 1mil low is NOT a coincidence. I DID do my homework. I collected field data that day, at that DA/altitude/BP/temp at 1 mile. Between that and my JBM data, I was able to make a very close approximation of the elev. needed to make that shot. I was VERY confident that I'd be close enough to at least be able to spot the miss. Shooters form notwithstanding, I then proceeded to put 3 more rounds in a 1 moa or less group at 2296 yds. That is NOT coincidence. Is it repeatable? As soon as I get a chance, I'll know. But automatically questioning the validity of our documented claims does not make for a healthy atmosphere that encourages growth.

I have learned much from this site and many helpful people here. I would like to continue on here and contribute and learn, but I would also like to see this place be a safe place where people can ask questions and make comments without browbeating. You and the other site leadership set the tone here. It is your house. I will respect it accordingly.

John

 

[MontanaMarine]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Brutas</div><div class="ubbcode-body">NBRSA 1000 YD Records 1.473 5 shot group.

http://nbrsa.org/node/65#attachments

Benchrest shooters are well known to be anal-retentive accuracy fanatics that spend tens of thousands annually on competition shooting. I have never heard of anyone that has won anything even mention coriolis effect. If it would improve there group size even .001 they would have 5 different methods for calculating and compensating for it.




</div></div>


Different objective. The BR competitors are about small groups. They typically shoot 'sighters' to get their dope lined up, before going on paper at 1K.

If you look at the top-tier 1K BR chamberings, they are making the trip to 1K in a fairly fast and flat manner, relatively speaking, as compared to a bullet making the transit to 2-3K yds.

 

[Lowlight]

Re: Rotation of the Earth?

I see everyone involved got butt hurt... no matter, it doesn't change a whole lot of my original point, which is clearly being side stepped.

Talk about shaving errors, accounting for everything humanly possible, and then we have grand results with using less detail than the average guy uses for target engagements inside 1000 yards. How it happened doesn't matter, three guys out having fun, good on you all. What you believe to be, clearly within your right for for others to decide. But again, I see "lots" of shooters, and the realities when then drive past the gates versus their home results rarely line up, even at our competitions, let alone our training. I would go so far to say, I have a vague knowledge what it takes to manifest consistent shots, inside and outside 1000 yards.

Bringing up something from 1989, I was in the Corps then, In fact our unit was one of the very first to receive .50 caliber sniper rifles, the Daisy type where you removed the bolt. I believe Dean even wrote about it in the HTI manual. Ours was an Iver Johnson 35lbs monster, although we took too it with the natural curiosity of the time it was quickly discarded by us personally, after some trial and error.

Now, let's look at that call from 1989, where has it gone ? What has transpired beyond the hobbyist among you ? Where is the government backed 3000 to 5000 yard Sniper Rifle ? Oh sure, plenty of claims, but nothing of value, certainly not deployed. I work with many, repeat, many sniper cells from more than one country, and I told you what the consensus was, you wouldn't believe me.

We shoot that far because we are arrogant and we can, doesn't have to be a reason, we just do it for fun. I applaud your efforts but only because it makes you happy and gives you sense of personal satisfaction, not because it has a practical long term possibility. Honestly I see more .50 cals NOT used than ever used by the military. Usually it is line units who enjoy breaking them out, mainly because they don't get the opportunities.

HTI is not about anti-personal, it anti material, meaning things much larger than a truck... we are not Hard Targets - a key distinction.

So, I will personally apologize to all involved, but make no mistake, if you claim you need the latest scientific doppler data to hit a target, you better not go out and hit it with anything less. Preaching the merits of details means practicing what you preach.

ELR is a vocal sub-genre, you spend a ton of money so you are infinitely invested in the results of your purchase as well your actions. Otherwise what is the point of the money spent ?

But as far as the military chasing the 3k Single Shot solution... good luck with that. The world is getting smaller everyday, and the need to shoot 3000 yards with a single small arm projectile shrinks along with it. trust me when I say the radio is a much more effective weapon at 3000. Still it won't stop our guys in uniform from making a beer bet, and the law of averages says eventually the trigger will win a round or two.

I focus on the man, not the hammer -- tools are easy.

 

[jrob300]

Re: Rotation of the Earth?

Frank,

Thanks for being open to feedback.

I for one can't comment strongly on the amount of math "needed" for ELR engagements as I've not done it that much. I'm really on the steep part of the curve here and trying new things and watching and listening.

There are those here who have a LOT more experience in this area and may care to comment.

I for one do NOT have a lot of money invested and intend to play as long and far as I can for as cheap as I can.

I will use whatever means available and necessary to continue to explore the outer reaches of my rifle. I don't know another way.

As far as technique, I do not claim to be an expert. I'm still learning. As I become aware of the need to improve in a given area, I seek out help and make adjustments.

Thanks again for a great site.

John

 

[Guest]

Re: Rotation of the Earth?

With all the complicated math you guys are using, I'd think just working a little closer would work also.

What happens when the Magnetic Poles Shift, you guys going to have to relearn anything?

 

[MontanaMarine]

Re: Rotation of the Earth?

Since this subforum is named "Beyond 1000 Yards" "High Performance at Extended Ranges" It kind of leaves the topic open-ended.

What is the maximum range open to discussion without offending your sensitivities?

 

[Lowlight]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MontanaMarine</div><div class="ubbcode-body">Since this subforum is named "Beyond 1000 Yards" "High Performance at Extended Ranges" It kind of leaves the topic open-ended.

What is the maximum range open to discussion without offending your sensitivities?

</div></div>

Clearly I wasn't the one "offended" I just don't consider hits on rocks valid, nor would I try to claim such as sub MOA considering it was 2300 yards away up a hill that I am willing to bet you didn't walk up to verify.

Not to hurt you or your friends feelings again, or to question your word, but you do know what a 1/4 mil subtends, I'd like to know the optic you used to measure the groups, to use the term loosely.

Call me a skeptic, call me an asshole, the choice is yours and trust me when I say I am not bothered by either, but well, any way I've said my piece. I just expected a little more hard data considering the nature of the noise we are questioning. I'm all about the latest and greatest, but.. Whatever.

 

[MontanaMarine]

Re: Rotation of the Earth?

How far?

 

[MontanaMarine]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">...2300 yards away up a hill that I am willing to bet you didn't walk up to verify....</div></div>

Is that how you verify the accuracy of a PLRF-10?

 

[MontanaMarine]

Re: Rotation of the Earth?

I was observing through a tripod mounted 16X Super Sniper.

If you hadn't noticed, your the only one here talking about 'feelings' and 'butt'.

 

[Lowlight]

Re: Rotation of the Earth?

You're joking right?

And I wasn't so much questioning the range as much as the group size.
I'll say rube goldberg has nothing on you.

Maybe you missed your buddies posts above, clearly they are upset with my line of questioning.

 

[Brutas]

Re: Rotation of the Earth?

There are exactly 1,398,462 variables involved with accuracy (give or take a couple hundred thou). Some of these can be proven scientifically, some can not. Some are more important than others.

MontanaMarine.. agreed different objective, equipment etc.. point was anything these guys can do to gain any bit of accuracy they will. They spend thousands of dollars and many hours sorting, weighing and measuring brass, bullets, etc.. (before trimming and after). They spend NO time or money on coriolis effect. Is David Tubb concerned about coriolis? The Tompkins/Gallagher clan concerned?

None of the PROVEN long range shooters are concerned about coriolis.

But 2000-3000 is soooo much different! Yeah right. Then why do the techniques of 100-200 yard benchrest shooters apply at all ranges?

Franks argument is correct. The most important variable is practice and experience.

 

[Lowlight]

Re: Rotation of the Earth?

The funny thing is, if this was so important, and they were convinenced they were truly making a difference promoting ELR everyone north of the equator would be adamant about using a left hand twist barrel as one of the necessary factors.

They like to talk about the math and science but when giving one solution to combat the effects, like the use of a left hand twist barrel for everyone shooting past 1200, that seems to fall by the wayside. Instead, the talk continues and they really aren't doing everything could.

I guess it is more fun to lobby rounds at rocks, and judge the results over a mile away with there 16X Super Snipers. ( which I hope was posted in jest)

I know that is what I would be using for a dedicated ELR rig. But I can be silly like that.

 

[Brutas]

Re: Rotation of the Earth?

Left hand twist barrels are available for a $300 upcharge.

 

[tullius]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MontanaMarine</div><div class="ubbcode-body">I was observing through a tripod mounted 16X Super Sniper.

</div></div>

Oh, never mind about all that Gaspar Coriolis stuff.. we need to get to the really important things: how many MOA is that rail??

 

[jrob300]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">You're joking right?

And I wasn't so much questioning the range as much as the group size.
<span style="font-weight: bold">I'll say rube goldberg has nothing on you.</span>

Maybe you missed your buddies posts above, clearly they are upset with my line of questioning. </div></div>

Frank,

For the sake of clarification, I was NOT questioning your line of reasoning.

"<span style="font-weight: bold">So easy a caveman can do it</span>"?

I was offended by the fact that you could not seem to stick to a friendly discussion but resorted to personal barbs in an attempt to bolster your case. I expect this from my 18 yo twins, but when I have a conversation with adults, it would be nice to keep it civil and respectful.

Perhaps you're not even aware that your style is a bit abrasive and designed to cause your opponent to run scurrying into a hole for fear of verbal reprisal. That's not the way to get people to contribute on a forum where the majority of the reason it exists is for <span style="font-weight: bold">discussion</span>.

I slip into this too from time to time, but it's not productive. If your motive for having this site is *really* to help people, EVERY member, learn and grow, then you have to treat ALL of them with a modicum of respect. I've read several comments here from users that probably just lurk now about how abusive it can be. Sure, laugh. My perspective. You can just dismiss me as being a lightweight, but what if there are more people here that feel the same way?

I got involved in this conversation because my shooting was used as an example here. I think MM was simply offering it as an example of the kind of distance that *might* require a little more consideration that your average backyard pellet gun shot. I'm fairly confident (correct me here MM) that he was NOT offering it as ANY kind of proof that:

a). we are masters at calculating Coriolis and SD which accounts for our phenomenal shooting

b). that we spent considerable time discussing said affects and spent any time whatsoever even taking them into account for those shots.

So, you can see, that the actual distance, group size, angle, barometric pressure, DA, phase of the moon or tidal patterns really mean nothing in this case. It was simply an example of the fact that we CAN shoot reasonably sized groups at these distances, hence we *might* take more factors into account *if* we want to make first round hits. For me it's bragging rights. I NEVER intend to point a loaded weapon at a living thing that far away. And I'm pretty sure the first round miss did NOT scare the rock. It'll probably be there for the rapid followup shot. BUT, if I can get to the point where I can start making first round hits on 1/4 mil rocks at 2300 yds. consistently, I'll probably post about it here, because I think that it is an achievable goal, something that requires skill and others may be interested, even if you personally are not.

Like I said before, It's your site, you run it the way you want. At the end of the day, I'm trying to help.

John

 

[MontanaMarine]

Re: Rotation of the Earth?

While Frank is flapping his wings and declaring what is and isn't possible with a rifle. men in the field are making ELR shots happen. Guess they didn't get the memo.

The Brits have made several kills past a mile recently with the 338s. One of our Army made a mile kill with an M24 in Iraq.

Those are the few I've seen lately, that got released to the press. You know there's more.



I'm done with you Frank. If you're still confused by all this, I can't help you.

 

[sobrbiker883]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">The funny thing is, if this was so important, and they were convinenced they were truly making a difference promoting ELR everyone north of the equator would be adamant about using a left hand twist barrel as one of the necessary factors.
</div></div>

Only if they shoot north all the time

Didn't you see "Shooter"?

 

[jrob300]

Re: Rotation of the Earth?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MontanaMarine</div><div class="ubbcode-body">While Frank is flapping his wings and declaring what is and isn't possible with a rifle. men in the field are making ELR shots happen.
</div></div>

With regard to your line of reasoning Frank, I do find it odd that on a website called Sniper's Hide, you seem to have taken the position that long range sniping is not a viable skill. Real world evidence <span style="font-style: italic">would </span>seem to point in a different direction. Those I've talked to have echoed your sentiments for the 50 BMG. It is primarily a hard target weapon. But the 300WM and 338LM both have capabilities well past their MER, and are and will continue to be used at ELR because at times that is all that is available. Current ROE in Afghanistan for the most part have taken that air strike out of your hands. Now what do you do?


John

 

[BryanLitz]

Re: Rotation of the Earth?

I've done a very good job of avoiding the spin drift and coreolis threads recently; a habit I developed after realizing that the majority of participants see the topic as a joke for some reason or another.

This thread seems to have a higher signal to noise ratio, having at least several people who seem interested in learning about the actual science.

I'll share a couple observations about the topic, and its discussion here on SH.

First, Frank.
To understand Frank's position, you have to remember what he's selling; which is marksmanship instruction. When you're selling marksmanship instruction, you'll be inclined to promote the idea that all problems can be solved with marksmanship instruction. "Pay me to teach you how to squeeze the trigger and you can do anything". "No need to learn about ballistics, or science, just squeeze the trigger. I'll show you how. For a fee."
In an offline discussion with Frank some time ago, we discussed the extent that spin drift and coriolis effect show up in 'real' shooting. Franks observation was that the right handed shooters tend to have shots/groups displaced to the right, while the occasional left hand shooter has his shots/groups displaced to the left. His conclusion was that the drift is more a function of the shooters position and trigger control than ballistics. However, (and this is the key) Franks shooters in the above example <span style="font-style: italic">weren't even using sight levels!</span>. So of course, without a device to insure zero cant, you'll have big problems with your lateral displacement at long range due to the effects of unseen rifle cant. This is a 'shooter'/'rifle' problem, not a ballistics one. <span style="font-style: italic">But for christsake, anyone serious about shooting 'Beyond 1000 yards' is going to have a level to zero out cant!</span>

Franks response to spin drift and coriolis threads are always the same, and the above is my rationale for why: He’s selling marksmanship instruction so every problem can be solved with marksmanship instruction.

So what am I selling? Well, I do have a book for sale, which explains the science of ballistics including spin drift and coriolis. So you should take what I'm advocating with a grain of salt just like Franks position. It's critical thinking 101: consider the source.

Now that the respective motivations are on the table, I'll offer answers, with actual numbers, to the questions about coriolis drift.

Rather than focusing on the horizontal component of coriolis [which always gets dismissed because it’s in the uncertain ‘wind plane’], this analysis will look at the vertical component of coriolis. I think we can all agree that the vertical plane has less uncertainty, so subtle effects should show up more profoundly. Plus the vertical component varies according to your azimuth of fire, which is much more likely to change in different scenarios than your latitude [upon which the horizontal component is a function].

The following analysis is for a .338 shooting 300 grain bullets at 2850 fps in standard atmosphere at 30 degrees north latitude (about middle of the US).

<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre> Trajectory
range north/south east west | Vert Miss Distance
1000 -242" -239" -245" | +/-3"
1500 -709" -701" -717" | +/-8"
2000 -1626" -1608" -1644" | +/-18"
2500 -3284" -3246" -3322" | +/-38"
</pre></div></div>

What the above results show is that if you're shooting 1500 yards (for example), and you don't account for the vertical component of coriolis, the most error you can have is if you're shooting due east or west, and it will be +/-8". This is a drift that's entirely deterministic [figure-out-able]. WHY would anyone choose to ignore it for ELR applications? It's 8" [in this case]. Who wouldn't want their hits to be 8" closer to center?

Fact: Any ammo will produce MV variation which will introduce uncertainty in your vertical POI. Maybe the uncertainty is close to the same magnitude as coriolis. Does that mean you should ignore the CE? Hell no. The variation in MV will give you a vertical 'band' to work with. Why not center that band over your POA rather than allow it to be high or low?

The above analysis [with numbers] is my attempt to illustrate the importance of considering subtle effects in ELR shooting.

Of course shooters should focus on the fundamentals of shooting, and obtain the best equipment possible for ELR shooting. Curiosity about the subtleties of ELR shooting shouldn’t be met with a blanket assumption that the guy is a bad shooter, or that his system isn’t capable of resolving the effects. So what if it’s not? Why not share what’s known about the subject and let each person decide for themselves if it’s a worthwhile consideration? Not everyone's trying to use science as an excuse. Some people just want to know.

Reference:
http://www.appliedballisticsllc.com/index_files/SpinandCoriolisDrift.htm

Equation for horizontal coriolis drift:
http://www.appliedballisticsllc.com/index_files/horizontal.jpg
Equation for vertical coriolis drift:
http://www.appliedballisticsllc.com/index_files/vert.pdf

Note these equations are provided for the benefit of those interested in calculating the coriolis effect. I’m not saying that everyone <span style="font-style: italic">has</span> to do it, but for those who care to know the details, there they are. You can decide for yourself if coriolis is something you want to concern yourself with.

-Bryan

 

[Lowlight]

Re: Rotation of the Earth?

Brian,

I don't argue the raw science and I do well to learn it and understand it, however my data, is real data and not modeled data...

You not only sell your book, you sell your service, you sell your Ideas like the G-7 among other things. You also work for company who has a vested interest in your credentials and your reputation as a Ballistican. So you have much more to lose than I do.

However I see shooters, lots and lots of shooters with many varying backgrounds, and the truth of the matter is 2 Mils in 20, again I noted this week with our class. I watched a Left Handed Shooter pull a shot at 100 yards on more than one occasion to the left by 1 MOA, again, at 100 yards by 1 MOA. You cannot dismiss that when shooting at 1000 yards we see as much as 2 Mils of difference in holds. I note it each and every time and I won't even get into Vertical Spread... that is a whole other matter.

Let's go beyond that, to moving targets, something I Don't see you discuss. The math is always 100% correct I will agree with that alongside side you every time. However, again we see about 1 Mil of difference at 400 yard among 10 shooters. This class the swing went from 2.5 Mils to 1.5 Mils hold for the same exact target at the same exact speed with the shooters using the same exact bullet. FGMM 168gr. I have the luxury at times to see 20 shooters all using the same gun, and bullet, and the variations are huge -- sure they are machines and vary, but people vary more.

Brian, I ask you this, how, can a man of science ignore the events on the ground ? Are you saying my position is wrong to fix the shooter first than add in the appropriate corrections later ? If they can handle it...

I don't dispute the effects of SD or CE, I however don't believe most are set up to take advantage of it and wouldn't know if they are seeing Wind, Shooter or SD... let alone of they have their rifle set up properly as you noted. People tend to avoid your caveats in your data and head right to the data. The disclaimers on your findings are tossed and all that remains is a scientific excuse for most out there. Sorry if I call it as I see it.

Where is the discussion on the wind speed increases associated to Max Ord ?

I am not promoting my services to anyone, you won't see me pimping my class to anyone... I can careless if anyone here comes to single class I work, but I will say the majority who do see a marked improvement in their shooting without the addition of SD at 600 yards and beyond. Don't take my word for it, read the reviews, if I was blowing smoke it wouldn't be hard to filter out.

Dismiss my observations all you like, say I am simply barking at you to sell a service... but since these discussions have started, I take note, and I point it out to each every class as it is happening.

The USMC Never preached or taught SD, not at 600 not at 1000, they also had Field Firing Solutions remove the references to it for their "Tactical" version, a direct request, I can show you version Delta 4 and Delta 5 where it is included, and Tactical where is is not... I guess they are selling something too. Show me in the USMC Scout Sniper Manual the reference too it as being necessary to hit the target. I think we as Marines have a pretty good track record for hitting shit at distance.

I find it hard to believe a winning competition shooter cannot acknowledge the poor fundamentals of MOST casual shooters, which I believe go well beyond the effects you are asking people to account for.

By all means if you reach that level of this sport, add it in, especially if your equipment can handle it, but really now let's be realistic for minute.

I am not selling anything, I work for someone else and our civilian classes are only about once every other month, and if you think that is all I work, well, okay.

Trust me when I say I would welcome the opportunity to put my line of thinking as well as my observations to the test... we can see which has more effect downrange the science or the shooter.