Help Needed with LB3.0 and .338 Bergers

[Eaglet]

If it proves that I need to enter a compass reading for azimuth and a gps for latitude to get it right, then I will use LB3.0. But so far I don't see the evidence. The first round hit yesterday at 1395 was done with only a dial up. Windage knob was on zero. Maybe it was luck? But if so I was lucky again today on 4 shots in 3 different directions and distances.

No disrespect ment by my posts. I simply call it like I see it. I know for sure all this has better educated me and for that I THANK YOU ALL!

More practise will tell.

Jeff

Jeff,

You pulled the trigger, the target is at 1500 yards away, the bullet is in the air, spinning like a maniac, as the bullet flies, your target is moving to another location. But why and where? Well, it's because of the earth rotating counter clock wise when viewed from the top of the North Pole; it depends in what direction you're shooting and where you're shooting from (Latitude). How do we fix it? Wait, depending on your barrel twist, whether is right twist or left twist and the twist rate; your bullet will be moving away from what the bullet path should be. Alright, so what do we do? Wait the wind is also blowing; it may be blowing in a way that is kind of compensating for the spin drift or helping the spin drift to move your bullet even farther away. ENOUGH!!!! What do we do???? Hold on, due to the Coriolis effect, there will be changes in two directions x, and y... this means vertically and horizontally... Shut up!!!! what do I do?

USE LB3.0 which will easily combine all these things into simple values that anyone can dial into their turrets.....!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Will Exbal do this?.... Not Exactly!...

Combined values... Yes!!! you don't have to do anything else... Just dial them in you turrets.

If it proves that I need to enter a compass reading for azimuth and a GPS for latitude to get it right, then I will use LB3.0. But so far I don't see the evidence.

Keep reading, you'll see it!

Exbal knows this is important, so it tries to do something about it. In the process it falls way short... I mean short.... Let's see some Exbal screen shots:

When you click on spin drift in image one, image two pops up telling you what to do to get your spin drift working... That's sad! Do you have the time to be doing this every time the conditions change. LB3.0 changes the needed values as the conditions change. Now that's easy, this here I won't even bother to use it. Does that make sense?

OK! When you click on Coriolis Effect, Image 3 pops up; I can't see it going over 1000 yards. Unless I'm missing something. Can you see the vertical and horizontal values that need to be either added or subtracted from your turrets because you have to do it... Man... you're in a hurry and you have to do this? Well I don't see Exbal combining the values with the regular turret values to where the user doesn't have to worry about it. Can you see how much it changes for a 308 Winch. at 1000 yards for the vertical and the horizontal? Now that's slow!!!!

See the evidence? You see Jeff, depending on the direction your shooting, and your location; because of the earth rotations you can hit either low or high and either right of left. That's a fact!!!

Let's see some LB3.0 Screen Shots:

Image 1: In Analyzer enter all the conditions you entered for zero conditions. Click the Results tab, click Miller radio button, check the Std Box. The value of 1.63 in the yellow box you will use in the Ballistics Module in image 3 for stability factor. This value will change automatically as the conditions change. You won't ever have to worry about it. In the same place you enter your Azimuth and Latitude for Coriolis Effect. Now everything you need for Spin Drift and Coriolis Effect has been set up!!!!!!!!!!!!!!!!! How do you like that?????? Is that a whole lot easier and way more accurate or what? Image 4 shows your come-ups for windage and elevations without any corrections; and image 5, right there!, by just checking on the boxes for Coriolis and Wind Drift you get the correction automatically in one shot!! THAT'S BEAUTIFUL!!! Any one following me???

Coriolis alone needs a correction of 0.6 moa left and 0.3 moa down. That's 9.42" left and 4.71" down.

Spin Drift alone needs a correction of 1.0 moa left. That's 15.71" left.

How would you like to be doing this in Exbal???

On image 5, by just checking the two boxes shown, it's all done for you automatically. Just dial it in!!!!!!!!!!!!! Baby!!!!!!!

Total Combined Correction to hit the target: 4.71" down and 25.13" left!

Remember, this is very cool, the 7 mph wind blowing from right to left, the wind Drift effect and the Coriolis effect were all combined for even my grand son can do it right without confusion!!!!!!!!

Can EXbal do this??? Show me!!!

 

[Pdvdh]

Broz,

According to the most recent drops & environmental data you provided, you stated:

So if this azimuth and coriolis thing really brings something to the table we can use 90* east and latitude of 46*.

Here is the dope from yesterday.

FC was all the same with the exception of temp I will note that with each shot.
Baro for all was 25.75
humidity 30

700 yards temp 68 10.75 moa needed
995 yards temp 59 20.00 moa needed
1182 yards temp 65 27.25 moa needed
1395 yards temp 61 36.00 moa used, one shot, 2" high

Jeff

Based on this information, your drops were:
10.75 moa
20.00 moa
27.25 moa
35.90 moa

Using these input values in LB3:
MV = 2753 fps
BC = 0.419
DC = 0.870

I get the following LB3 predicted dope, with coriolis activated:
_700yd 10.5 moa -> 1.8" low
_995yd 20.2 moa -> 2.1" high
1182yd 27.1 moa -> 1.8" low
1395yd 36.0 moa -> 1.5" high

Your measured drops on this shooting create a bit different bullet curve than the data in your initial post - Post #1 in this thread. I obtained a better fit with this reduced MV than with the higher MVs of 2771, 2780, or 2800fps.

For what it's worth...

 

[Broz]

Boys I am only telling what I see. I will try to make this brief. I take pains to square my scopes. A plumb vertical line on cardboard 40" high. I shoot 3 at the bottom, dial up 25 or 30 moa and shoot a few more at the same point of aim. If the upper hits are not on the plumb line I rotate the scope and shoot again till they are. All this is done with a anti cant device of course.

I simply dont put as much stock into the Spin drift and coriolis that you do. I don't feel it is quite that significant at only 1000 or 1500. Especially with some rifles or bullets.

At some point in any scientific experiment, you need to leave the computer and get real world results. This is what I am going to do. If I see a definate pattern that I am shooting right I will start to look at Spin drift.

I will add, in my opinion, not all rifles/bullets react to spin drift the same. Some may pronounce it more. This is just from my experience shooting a lot with different rifles.

Jeff

 

[bigbuck]

Broz,

I use Exbal butI havn't had it very long. I understand that shawn carlock uses it as well . When I firstread a post someone had started about LB I thought to myself man I should have got that program . I'm glad that i ended up with what I've got now because i'm not to good with computer skills . In my opinion if your a computer junky and that floats your boat then I could see were the LB program would rule . However if i could do the same thing with Exbal then why go through all of the head scratchin when one could be shootin

Question Broz. Have you shot at the target in front of your garage that you posted a picture of with exbal .

If exbal could produce a cold bore shot at the same distance with out all of the computer programing skills then Exbal still kicks LB's hiney !!!

Have you tried exbal with the new berger 300 grainer yet ?

I've been following most of this thread (although it seems like spanish to me) You fellas really know your stuff . but i will have to agree with Broz at some point you have to get real world data if nothing else just to confirm that the drops are spot on !

BigBuck

 

[jmden]

Boys I am only telling what I see. I will try to make this brief. I take pains to square my scopes. A plumb vertical line on cardboard 40" high. I shoot 3 at the bottom, dial up 25 or 30 moa and shoot a few more at the same point of aim. If the upper hits are not on the plumb line I rotate the scope and shoot again till they are. All this is done with a anti cant device of course.

I simply dont put as much stock into the Spin drift and coriolis that you do. I don't feel it is quite that significant at only 1000 or 1500. Especially with some rifles or bullets.

At some point in any scientific experiment, you need to leave the computer and get real world results. This is what I am going to do. If I see a definate pattern that I am shooting right I will start to look at Spin drift.

I will add, in my opinion, not all rifles/bullets react to spin drift the same. Some may pronounce it more. This is just from my experience shooting a lot with different rifles.

Jeff

It'll be very interesting to follow your shooting for a few days here and see what you find in regards to the Hybrid, Exbal and LB... Keep us informed, OK? Thanks, jon

 

[bigngreen]

Broz, I completely understand what you saying, we have some rifles that I don't use any Coriolis or spin drift on, I think eventually they would at some distance but I haven't reached that distance.
On the other hand we shoot a 40-65 black powder cartridge rifle that will spin drift 3MOA at 1000yrds, I need all the tools in LB to put it on target. My LRH rifle doesn't need anything more than elevation and windage till around 900yrds then I start taking Coriolis and spin drift into the dope.

I find some computer programs work in a way that I can't wrap my brain around it then there are others that just click, I'm stuck in the middle on techy stuff, I can do and know just enough to be dangerous and I have to work to get it. Thank God that there are choices for use to choose what we can easily make work.

Loadbase clicked for me as far as how it works and I can navigate it fast, but it took a lot of hard work to understand the ballistics behind the numbers I was entering, things as simple as Station and Corrected pressure took me a lot to wrap my mind around when I use what to get the most accurate correction.

Bottom line, cold bore hits with spot on corrections are the pay of and will make the most hardend person giggle with glee. What ever method gets a guy there, LoadBase 3.0, Exbal, JBM or range cards is what you have to go with, bottom line!!!gun)

 

[jmden]

Broz, I completely understand what you saying, we have some rifles that I don't use any Coriolis or spin drift on, I think eventually they would at some distance but I haven't reached that distance.
On the other hand we shoot a 40-65 black powder cartridge rifle that will spin drift 3MOA at 1000yrds, I need all the tools in LB to put it on target. My LRH rifle doesn't need anything more than elevation and windage till around 900yrds then I start taking Coriolis and spin drift into the dope.

I find some computer programs work in a way that I can't wrap my brain around it then there are others that just click, I'm stuck in the middle on techy stuff, I can do and know just enough to be dangerous and I have to work to get it. Thank God that there are choices for use to choose what we can easily make work.

Loadbase clicked for me as far as how it works and I can navigate it fast, but it took a lot of hard work to understand the ballistics behind the numbers I was entering, things as simple as Station and Corrected pressure took me a lot to wrap my mind around when I use what to get the most accurate correction.

Bottom line, cold bore hits with spot on corrections are the pay of and will make the most hardend person giggle with glee. What ever method gets a guy there, LoadBase 3.0, Exbal, JBM or range cards is what you have to go with, bottom line!!!gun)

BnG,

That's some interesting information you relay there. Have you found anything besides just testing a certain load with a certain rifle and a certain range that you can point to that will tell you if you might need to use the spin drift and coriolis inputs in LB?

I've used Exbal about 3 years now is all and do not have LB--would like to get it however. The spin drift and coriolis in Exbal seems a little cheesy to me, but again, like some others, I'm not sure if I need that info. But, not being able to do a great deal of shooting... I need to do alot more real world shooting in widely varying conditions and taking careful notes, I guess.

Jon

 

[Pdvdh]

I obtained the effect of substantial L to R drift with one 7mm Rem Mag rifle because the scope wasn't mounted parallel to the bore in the left/right plane. This kind of thing doesn't play a significant role until the target or game are engaged at the farther ranges we find challenging. I didn't know the scope's alignment was off enough to create the excessive L to R drift until shooting at 1000 yds with it and my 300 Win Mag at the same time one afternoon. Both rifles sighted about 3" left @ 300 yds to allow for Coriolis and spin drift @ 1000 yds. The 7mm Rem Mag drifted quite a ways rightward compared to the 300 Win Mag. Too much to be explained by combined Coriolis and spin drift. I wrote this experience up in a Thread on this Forum back in 2008. This was the beginning of the research effort for me. The quest to get my arms around these mysterious causes of drift.

http://www.longrangehunting.com/forums/f17/left-300-yds-right-1000-yds-wth-35255/

To cut to the chase; I finally removed the scope, ran a long straight edge along each side of the scope rail and observed the gap between the straight edge (a 4' level works as a straight edge) and the muzzle. Along one side of the scope rail, the straight edge was over the middle of the muzzle. Along the other side of the scope base rail, there was ~ 5/8" gap between the side of the barrel and the straight edge. I loosened the two-piece scope base, re adjusted those mounts to get the straight edge running parallel to the bore, remounted the scope, headed back out to the 1000 yd target - Problem Solved. Now the L-R drift was about the same as with my 300 Win Mag. Then when I ran the dope through LB, the L-R drift I was observing was precisely accounted for with the combination of spin drift and Coriolis drift.

Now I always use one-piece scope bases, I always use the straight edge to confirm my scope base is running parallel to the bore, I always level the bore and scope's objective plumb with gravity using a tool/device obtained from Brownells, I always mount an anti-cant level to the scope rail or scope tube, after using the Brownells tool I always hang a plumb bob down the driveway and then rotate the scope tube until the vertical cross hairs are overlapping (in vertical alignment with) the plumb bob string, and I always then note the position of the level bubble (reading) on my anti-cant device. If it's mounted on the scope tube I rotate the device to level the bubble when the vertical crosshair overlaps the plumb bob string. If my anti-cant device is mounted on the scope rail I will mark new bubble level lines to calibrate the bubble to the real world level conditions I just established when the scope's vertical crosshair overlaps the plumb-bob string (if the unit's bubble calibration lines are incorrect). In other words - everything is plumb to the bore in the vertical direction, aligned with the world and aligned parallel with the force of gravity. Since adopting these standardized scope mounting practices, I have no surprises with either a lack of spin drift or coriolis, or an excess of spin drift or coriolis.

I accept that coriolis is always in play. If Isaac Newton and Albert Einstein proved it, I accept it. Believing or not believing makes no matter to Coriolis drift. Should the world stop spinning, then I'll forego the dope for Coriolis at long range. It's a proven fact that it is affecting POIs at long range unless you live, shoot, and hunt at the Earth's equator.

I also accept that spin drift is in play with every rifle I've zeroed at 300 yds and fired in windless conditions at 1000 yds. It's admittedly less predictable, more variable, and consequently more difficult to model than Coriolis. But modeled dope for spin drift is almost certainly going to result in a closer POI than no dope at all.

Factors I've experienced and/or am aware of that could offset Coriolis and spin drift (L to R drift) without shooter awareness are 1) canting of the rifle to counteract these drifts, 2) mounting the scope non-parallel to the bore in the left to right plane which will serve to either counteract or exacerbate apparent drift, and 3) crosswinds which can add to or subtract from these two sources of drift. If others know of additional masking factors, please sound in.

I've heard the opinion more than once that wind doping so grossly controls L to R dope that Coriolis and spin drift get lost as background noise compared to wind drift. But then at least one member with that opinion admitted he lived in tornado alley. The strong prevailing winds where he shot didn't make it worth the bother to dope for Coriolis or spin drift. Again, with respect to other's findings and preferences, I say live and let live.

The sport is intended to be enjoyable. Don't ruin it by making it overly complicated if you dislike complication. Or if you enjoy the additional complication in doping for mysterious drifts, than add LB to your arsenal and factor in Coriolis and spin drift. If you don't see them on target it's not because they aren't in-play. They're occurring surely as the sun rises in the East and sets in the West.

 

[jmden]

Thanks for you comments above, phorwath...

 

[bigngreen]

The sport is intended to be enjoyable. Don't ruin it by making it overly complicated if you dislike complication. Or if you enjoy the additional complication in doping for mysterious drifts, than add LB to your arsenal and factor in Coriolis and spin drift. If you don't see them on target it's not because they aren't in-play. They're occurring surely as the sun rises in the East and sets in the West.

That sums it up well!!! I love the little details and learning how it works and why it happens, it is way over my head and way beyond my math skill but I still try to get my mind around it some how.
Some guns I have I can tell that Coriolis and spin drift are a factor, so I assume the one's that don't seem to be affected are set up in a way that the correction is built in, I'm trying to find out what make those guns different because I know there is a correction being made without my input and I want to control all the correction that are happening.

With one gun, at first I blamed a bad correction on the program or the wind meter but the actual problem has been spin drift all a long, I'm just starting to take Coriolis into acount because I'm just now getting to the ranges where you can tell it is a factor.

I have Litz's book on the way, I think that it may really help me get things squared away.

 

[Broz]

Qestion, why with LB , sometimes when I activate the coriolis, it will raise or lower the elevation come ups? Sometimes .3 moa or more. The problem with this is. I shoot and see what is needed for a center mass hit. At times I turn the coriolis on and the come up is correct. At times it is correct before I turn it on and incorrect after ?

Jeff

 

[Broz]

Broz,

Question Broz. Have you shot at the target in front of your garage that you posted a picture of with exbal .

Have you tried exbal with the new berger 300 grainer yet ?

Yes, I am using both programs for each shot to see which works most accurate for me. The come up in exbal for the 1395 yd cold bore shot was 35.75 moa. The come up with LB was 36.2 I used 36.0 for the shot, and it was 2" high of dead center. That being said if I would have sot 3 for group, and was lucky enough to hold my 1/2 moa average or close. The group would have been close to 7". So, I cant say that 2" high for one shot is accurate to the inch for a come up. But I will say, I would feel comfortable taking that shot at game and being successful.

Yes, all of this started with me shooting the new me 300 gr Bergers. I was having trouble with my come ups matching up with exbal. So I purchased LB 3.0. I was still having trouble dialing it in. Then Berger announced the new BC's. Now, with the new BC's all seems to be on track with both programs.

Jeff

 

[Pdvdh]

Qestion, why with LB , sometimes when I activate the coriolis, it will raise or lower the elevation come ups? Sometimes .3 moa or more. The problem with this is. I shoot and see what is needed for a center mass hit. At times I turn the coriolis on and the come up is correct. At times it is correct before I turn it on and incorrect after ?

Jeff

Don't hold my feet to the fire; but a 90* and 270* azimuth shot will be affected by Coriolis-induced bullet climb or fall (vertical change in dope), in addition to the horizontal drift. The horizontal drift is the same no matter which direction you shoot, and is based soley on your location in degrees North Latitude. Vertical dope is unaffected with a dead north 0* azimuth and a dead south 180* azimuth. Shifting azimuth either easterly or westerly from due north or south will affect vertical Coriolis-caused dope, with the maximum dope required when firing due east and due west. Shooting due west will result in a lower Coriolis-caused bullet POI; requiring additional elevation dope. Shooting due east will result in a higher Coriolis-caused bullet POI, requiring less elevation dope.

Play with this on your LB program and I believe I have relayed these Coriolis affects on bullet flight correctly. Plug in a 1000 - 1500 yd range and 0* azimuth. Turn coriolis on and off and elevation dope should not be affected. Then enter a 90* azimuth and turn coriolis on and I believe elevation dope will be reduced. Try the same with azimuth = 270* and coriolis turned on should increase vertical dope. Try the 180* azimuth and coriolis should not affect vertical dope.

I don't have LB with me at the moment or I would confirm this first. But I'm pretty sure. If this is wrong, post back here and notify me I'm the one full of the dope!

PS: No matter what you decide on spin drift, I highly recommend the inclusion of Coriolis drift when using LB3 at long yardage, because Coriolis bullet drift, climb, and fall is as well documented and modeled as gravity. I recommend spin drift also, based on my testing and experiences. But I am led to believe that pinpoint accurate modeling of spin drift is a bit more elusive than the modeling of Coriolis drift.

 

[Eaglet]

In Bryan Litz Ballistic Book we find very interesting formulas.

Let's use a couple of them.

a 338 gr. SMK bullet out of an Edge at 2800 fps would take about 2.229 sec. of TOF to get to the target. using 1:10 right twist.

Using the formulas:

Spin Drift alone, at 1500 yards move the bullet to the right 19.2"

I'm asking, please, I'm asking to how many of you this information should not be considered or taking into account? To how many of you to make it simpler and less computerized would like to ignore this info???

Let's say the wind is blowing and at 1500 yards is moving your bullet 18" left which takes very little to do that. You don't make any corrections for anything and hit the target very close enough. Then you call you shot awesome. And it is!!! you just were very lucky!

Let's say there is absolutely no wind. For sure! No wind!
you make no adjustments and you rifle hits the target pretty close to the center. Where most would say that rifle is right on, I would know for a fact that the rifle is off!!!