Roys path to quick and easy use of scope turrets.

4ked Horn

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Jun 13, 2007
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Here is the post I promised you Roy. It will be a very brief explanation of the 3 data input screens on the Big Game Info ballistic calculator as I understand them. I sent an email to the creator of the site but it was rejected as a email no longer in use. I was hoping he would come help me out.

I will explain each screen shot and at the end I will use this info to demonstrate how I set and adjust my scope. From there you will need to ask questions untill it makes sence to you. You should be able to shoot a range with a laser and dial for range in seconds. Then you should be able to make a judgement on wind and dial accordingly again within a few seconds. When done shooting you should be able to reset your scope to zero to wait for another day.

Here we go. /ubbthreads/images/graemlins/cool.gif

Once you open the websites advanced ballistic calculator and log in if you wish you will view the "load definition" page. It will look like this.

338loaddef.JPG


Muzzle velocity and chrono distance should be easy enough. If you set your chrono at 10 feet from the muzzle then put this in the field and input the velocity the chrono gives you. This program will calculate the MV backwards from 10 feet when we get to the data output fields.

Zero range is the distance you want to call home. We have discussed this before. I reccomend a 100 yard zero. Dont worry about fast shots on coyotes here. We will handle that neatly later on. If you are shooting a gun like the MOAG then you may want to change this to a greater distance but I really believe that for now 100 wil suit our needs.

Height is where someone might put 2 inches if they are shooting 2 inches high at 100 so they can shoot coyotes on the move at 300 and be zeroed at around 200. FOR NOW OUR GUN WILL BE ZEROED AT 100 WITH A HEIGHT OF 0. We are hitting the center of our 100 yard target.

In Bullet start with a drag function of G1. This is standard. Later, if you wish you can compare the other drag functions. GI (used in this screen shot) and GL are fairly close to some of the ULD designs if I'm not mistaken. Regardless, you can experiment with those later.

You will see that I entered 3 BC values for your bullet. The designer of this program did that to allow the info that the Sierra website gives you. Just enter the BC and the top velocity it is listed for. If you only have one BC value then put it in the top cell and give it a velocity max of 5000.

Sights height is the center of the scope to the center of the bore.

Clicks / MOA is the nember of clicks per MOA for your scope. This will effect the way the results will appear so get this one right.

Elevation is NOT your altitude. Leave a 0 in this cell untill later on. The calculator will tell you what to put here later. As you see in the screen shot I have entered a value. I'm sorry but even after an explanation from the site owner I still don't understand what this "elevation" does exactly. Most of the time I leave a 0 in it.

Next page coming.

<font color="red"> Please hold other responses untill I get all 5 images of this lesson posted.Thanks. </font>
 
I forgot to mention above that you do not need to click on calculate untill you finish all 3 input pages. Then you can click it all you want after tweaking info on each of the three pages.

The next page is Atmosphere.

338atmosphere.JPG


This should be pretty straight forward.

If you want to use the standard conditions at altitude then enter only the altitude and click the box. The screen will refresh with the standard values.

I preffer to set the wind direction at 90 degrees (full value) and 20 MPH. This makes the results easy to calculate in my head for slower wind or wind coming at a different angle.

Simple simon so far. If I am going rock chucking all day I will print the results for my drops using 3 different temps for morning mid day and warm afternoon.

Next page. My favorite.
<font color="red"> Please hold posts for the end. </font> /ubbthreads/images/graemlins/wink.gif
 
Preferences. This is the fun stuff. This screen is the flexible backbone of this site.

338prefs.JPG


Ranges. This will tell the program the part of your trajectory you want to see and in what incremental step. For starters set the minimum at 0 or 100 and the max can go out to 2000 if you want. I suggest using a number here that is realistic for your normal uses so you don't get bogged down with too much info.

Your interval option is very cool. You can set it for 1 yard steps if you want and then if you wanted to mess with a spreadsheet long enough you would have a yardage value for EVERY click of your scopes elevation. Holy CRAP!! For now use something more productive like 20 or 25 yards. I used 50 so we could show a farther distance on the screen shot.

The target speed and angle section helps calculate leads for moving game. This is fun to look at but I personally find it of little use in long range shooting for a drop chart.

The vital zone radius is VERY handy however. The
The Vital zone radius is what we will use to calculate a Point Blank Range (PBR) and max PBR (MPBR). This is what we use for the coyote that comes into view at 283 yards looking like he wants to hit the road. If you are shooting deer or elk or ground squirrels you can change this number for this PBR shooting I will explain later.

The incline is like the Temp option in that you can add a few columns of angles you are likely to encounter to your drop card to help you as you hunt different areas.

Now for the output columns.

Yardage. This should be automatic. It is the column that indicates the rang that each row of the chart corresponds to. Duh. /ubbthreads/images/graemlins/tongue.gif

The next four options are the different ways the chart can communicate your bullets parabolic path to the ground.

Inches is self explanatory. Try dividing the numbers in this column by 12 sometime to see how many feet a bullet really drops. It is amazing.

Come ups in clicks. This is the column I am trying to wean you from. This is for short rangers sighting in their gun for the season where they only need to count a dozen or less clicks. Clicking for extended ranges (300+ yards) should not be counted in my opinion. There is too much room for error and it takes so stinkin' long. Lets look at the next two columns. This is where your future is.

Come ups in MOA+ clicks keeps things simple. Follow me. If you want to adjust from your rock solid 100 yard zero, that you are confident is correct, up for a 532 yard shot you will use this column to do that. In conjunction with the numbers and hash marks on your scopes turrets you will rotate your elevation knob by large MOA movements and then count off the remaining clicks. In your case you will not count any more than 7 clicks. This column is your golden info. You don't have to know how big a MOA is at 478 yards. You don't need to calculate a click value or add 326 yards to 213 yards. You look for the closest yardage on your range card then look in that row for your come-ups in MOA+ clicks and go to that place on your knobs. It is an address on the rotation of the knob that corresponds to the yardage you are hitting at.

Come ups in mills is for those of us with a Mill dot reticle. You can use visual holdovers to engage targets. It is a wee bit quicker than cranking knobs but not quite as accurate. It is a toss up. Kirby Allen likes it and he brings home the meat.

Velocity, energy, momentum and time of flight are raw info columns. It will help you know when your bullet goes subsonic or where your bullet retains less than 1000 foot/pounds. Handy stuff to know but not for a range card.

The four windage columns are like the elevation columns. Inches is interesting, clicks are archaic, MOA+ clicks are your friend and Mils are for quick reference.

The required lead column corresponds to the target speed and angle info you entered earlier for shooting moving targets.

Optimum game weight is a reference that has been put together for a reference. Take it for what its worth.

Whew. It is 5:30 a.m. can you believe that. What is wrong with me? Oh, thats right. I woke up 2 hours ago coughing and couldn't fall asleep.

Lets carry on. Here come the screens. hehe /ubbthreads/images/graemlins/grin.gif

<font color="red"> 1 more page coming. </font>
 
Here is the info we just called on the calculator to generate.

338chart01000.JPG


At the very top is the elevation we skipped over on the load definition page. You can go back and enter it if you want but I don't know quite what benefit it is. In fact it will muck things up if you try to display the same chart with a 200 (or whatever) yard zero.

Your PBR has been calculated for you. Here it is 259 yards and your MPBR is 304 yards. This means that if today, you are hunting coyotes like Remingtonman25-06 you adjust your scope when you head out as though you wanted to shoot 260 yards. About 2 MOA+ 2 clicks. Then if you see a coyote out to 304 yards you simply aim dead center up and down. The bullet should not fly higher than 3" above the line of sight and drop to 3" lower than the line of sight at 304 yards. These numbers will change with flatter trajectories or larger or smaller kill zone radii.

Take a few moments to look at the chart. There is alot of stuff going on here but I'm sure you are familiar with most of it.

Now again lets focus on the come-ups in clicks and in MOA= clicks columns.

We long range shooters shoot at 400 yards fairly often. It would be silly to sit there counting,1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44 clicks. Or was it really 45? One extra click at even this range is a miss on a ground squirrel mellon shot.

Instead of counting clicks use the numbers and marks on your turrets to simply turn 1, 2, 3, 4, 5, MOA and click, click, click, click. DONE.

If you then see a coyote at 700 yards simply go up to the next full MOA (that would be 6) and go up from there. 6, 7, 8, 9, 10, 11, 12, 13, 14. (or 1 moa short of a full rotation if you have 15 MOA turrets), breathe, aim, squeeze. DEAD YOTE!!!

Yes you will have to figure in for wind but the adjustment should be all the same.

Now lets look at a simple range card.

338rangecard.JPG


Here are the basics. If you dont have a Mil dot reticle then don't select this option. You can also highlight and copy and paste this chart directly into a microsoft excell spreadsheet with little effort. You can then recalculate for different temps and inclines of shooting and paste this stuff into the same spreadsheet. Then you can scale it down so when you print it and cut it out it will fit on the non cheek side of your stock.

OK I'm stopping here. I'm tired again and it is 6:15 a.m. I might get 2 hours sleep before the kids get up.

Let me know if you have any questions Roy or anybody else. I hope this helps someone.
 
Well, thank you Sir!!!!

I appreciate your diligence, I'll buy you a burger one of these days.

I was getting hung up on that wierd elevation thing, plus was a bit confused by the several BC entries and max velocities.

The web says that is uses the JBM algorithim (cool word) (watched Numbers again last night}.

This should make things handy for determining unknown BCs and makeing corrections to published BCs as the need arises.

Again, thanks for the tutorial /ubbthreads/images/graemlins/smile.gif /ubbthreads/images/graemlins/smile.gif

BTW, regarding any velocities that I have provided for the 338 Win, I think they should be disregarded. They are way, way to hot. GG and the boys said its a bomb waiting to blow.... I think I was just below major plastic deformation of case heads, i.e., one shot per case then throw it away. I was getting about 5 rounds per case then the primers wouldn't stay completely in the pocket. Pulled the barrel and replacing it w/a RUM bbl.
 
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I appreciate your diligence, I'll buy you a burger one of these days.


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That day is coming. The rockchucks cause us to migrate East at least 2 or 3 times a year. I'll take you up on it.

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regarding any velocities that I have provided for the 338 Win, I think they should be disregarded.

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No problem. I always load according to the books and check my own pressure signs. Never used a recipe I haven't read in black and white with a million dollar companies name on every page.

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Again, thanks for the tutorial

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There will be a test. If we ever get together for a shoot and we catch you counting clicks we will only spot 300 yard chucks for you so you don't run out of fingers and toes. /ubbthreads/images/graemlins/tongue.gif

This reminds me, did you catch my "on purpose" error in one of the above posts? I did it to reinforce a point.
 
Thats the same program I have been using for about 2 years. Good thing is its free, and it works! Of course shooting and verifying is always a smart thing to do. /ubbthreads/images/graemlins/cool.gif
 
Do you understand the counting MOA instead of clicks thing? Do you see how to use the calculator to determine your PBR for shooting coyote pop-ups?
 
to be completely honest, no I still dont understand MOA. I understand clicks though. I know how to divide by 4, get the number on the scope, then add the remaining 1, 2, or 3 clicks. I have a chart taped to the side of my stock with the range from 250 yards, to 1000 yards in 25 yard increments with the corresponding # on scope to range. That way in the field all I have to do is range, then look at the side of stock, see what # to go to, then click up. I dont count clicks in the field. Thats way to slow. MOA is just a different language to me it seems, I never have really understood it, and I dont see anything wrong with the way I have been doing it. It works for me, so I haven't changed. For instance if I had to go up 113 clicks, that 4 goes into it 28 times with 1 remaining. On leupold scopes, you have 60 clicks for one full revolution. So I would go past my "0" 1 time, thats 15x4=60 clicks, then I have 13 moa left, plus the extra 1. so 13x4=52, so I would have to put it on 13.1, after 1 full revolution. May sound confusing, I have a hard time putting it into words maybe, but I can do this way in my head pretty easy.
 
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It works for me

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Can't ask for more than that. /ubbthreads/images/graemlins/laugh.gif
 
Went to that BigGame site and down loaded the SureShot software for the Pocket PC, Ipaq in my case.

Took a while to get it running. His instructions for downloading the .NET thinger didn't work. Had to download the DotNetSDK thinger (25mb) When installed everything took off.

Do your base load on the web. Then sync in the SureShot program on the Ipaq and then all you're asked for are the atmospheric conditions and up/down shooting angle.

The bummer is that it only shows the Path in Inches and the comeups in clicks.

Like Kirby, I'm a mil dot hold over user. But I run into the bottom post at 890 yds. Think I can sneak closer than that to an Elk????

Thanks, again
 
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