trajectory help please...

grit

Well-Known Member
Joined
Mar 23, 2005
Messages
1,375
Location
Utah
Did some shooting today. I recorded my poi's, to build a data card. I've played with a couple ballistics calculators, and can't quite tweak them to get the same results.

Rifle: Winchester 70 24" sporter
caliber: 270 win
load: 140 grain sst bc-.495
RL19 56.4
federal 210
remington brass
Mv: unknown

Come ups required for poa impact:
500 yards- 8 moa
600-10.75 moa
700- 14.25 moa
800- 18 moa

Temp: 55 degrees
Elevation: 4000
Cant: 5 degrees

Can someone help me build a card from this info? Why can't I get a match?
 

Tim Behle

Well-Known Member
Joined
Mar 16, 2002
Messages
367
Location
McNeal, AZ
I'm in the same boat as you. It would be nice if someone would come up with a ballistics program that would allow you to put in actual drops and bullet speeds for each shot, then adjust bullet's BC and create a working drop chart.

One load I worked up a few days ago, the Point Blank program said that I'd need 16 3/4 MOA to be on target at 800 yards. Turned out I only needed to come up 12 MOA. But it won't let me Input the actual numbers.

Sometimes I think these Ballistic programs are designed by Dan Lilja. Because by the time I get a barrel figured out, it's shot out and needs to be replaced!
 

CAM

Well-Known Member
Joined
Jan 2, 2002
Messages
385
Location
Utah
grit

I don't shot a 270 so I could be way off base here.
with the info you gave, the key is 10MOA between 500 and 800

Try 2935 Fps with a 150 yard zero

CAM
 

edge

Well-Known Member
Joined
Nov 4, 2005
Messages
1,088
What is the height of the sight above the muzzle?

Are you Zero MOA @ 100 yards?

Best guess as to MV?

Adjusted B.C.( 0.570 ) or Sea Level B.C. (0.405 )??

edge.
 

royinidaho

Well-Known Member
Joined
Jan 20, 2004
Messages
8,950
Location
Blackfoot, Idaho
You entered the realm where I once was. The problem is that I'm still there /ubbthreads/images/graemlins/grin.gif

Gotta run to work at the moment, will respond later today if some one else doesn't nail it.

If you have some time and have microsoft excell build a table of you data and graph it. Then generate the equation for the curve. Do whatever gets the best fit. R = 1 for perfect.

If all of this is jibberish, I'll do one for you and send it.

You don't have to worry about the unknown velocity. Just so the drop chart works.

Heck, all you wanna hear is "bonk" /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
 

edge

Well-Known Member
Joined
Nov 4, 2005
Messages
1,088
[ QUOTE ]
SNIP

You don't have to worry about the unknown velocity. Just so the drop chart works.

Heck, all you wanna hear is "bonk" /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

[/ QUOTE ]

For your needs Roy in Idaho is right.

If you want to use a program then you either need more info or just play with the numbers.

I would like a few of the closer drops for back testing your curve.

edge.
 

Dave King

Well-Known Member
Joined
May 3, 2001
Messages
2,366
This is close although it may be of no value. You'd need to check your 100 yard zero and some of the other intermediate ranges.



Velocity (fps)......3060
Bullet Weight (gr)..140
Bullet BC..............0.430
Start Distance......0
Range Increment...25
Altitude (ft)........4000
Temperature (F)....55
Scope Height (inch).1.75
Mil Value (3.44, 3.6).....3.440
MOA value (1.0, 1.047)..1.047
Zero Range (yds)........100


<font class="small">Code:</font><hr /><pre>
Range Vely Energy Total Bullet MOA Mil
yds fps ft/lbs Drop Path Drop Drop
0 3060 2910 0.0 -1.8 0.0 0.00
25 3010 2816 -0.1 -0.9 -3.6 1.05
50 2961 2725 -0.5 -0.4 -0.7 0.21
75 2912 2635 -1.1 -0.1 -0.1 0.02
100 2864 2549 -1.9 0.0 0.0 0.00
125 2817 2466 -3.1 -0.2 -0.1 0.04
150 2770 2385 -4.5 -0.7 -0.4 0.12
175 2723 2304 -6.2 -1.5 -0.8 0.23
200 2677 2227 -8.2 -2.5 -1.2 0.35
225 2632 2153 -10.4 -3.9 -1.6 0.48
250 2587 2080 -13.0 -5.5 -2.1 0.61
275 2542 2008 -16.0 -7.5 -2.6 0.76
300 2498 1939 -19.2 -9.8 -3.1 0.91
325 2454 1871 -22.8 -12.5 -3.7 1.07
350 2411 1806 -26.7 -15.5 -4.2 1.23
375 2368 1742 -31.0 -18.9 -4.8 1.40
400 2326 1681 -35.7 -22.7 -5.4 1.58
425 2284 1621 -40.9 -26.9 -6.1 1.76
450 2242 1562 -46.5 -31.6 -6.7 1.95
475 2201 1505 -52.5 -36.7 -7.4 2.15
500 2161 1451 -58.8 -42.1 -8.0 2.34
525 2120 1397 -65.9 -48.2 -8.8 2.55
550 2080 1344 -73.2 -54.7 -9.5 2.76
575 2041 1294 -81.0 -61.5 -10.2 2.97
600 2002 1245 -89.2 -68.8 -11.0 3.18
625 1963 1197 -98.1 -76.7 -11.7 3.41
650 1925 1151 -107.5 -85.2 -12.5 3.64
675 1887 1106 -117.5 -94.4 -13.4 3.88
700 1850 1063 -128.2 -104.1 -14.2 4.13
725 1813 1021 -139.8 -114.7 -15.1 4.39
750 1777 981 -151.9 -126.0 -16.0 4.66
775 1742 943 -164.7 -137.8 -17.0 4.94
800 1707 905 -178.3 -150.5 -18.0 5.22
825 1673 870 -192.5 -163.8 -19.0 5.51
850 1639 835 -207.7 -178.1 -20.0 5.82
875 1606 801 -223.4 -192.9 -21.1 6.12
900 1573 769 -240.1 -208.6 -22.1 6.44
925 1540 737 -257.9 -225.4 -23.3 6.77
950 1508 706 -276.1 -242.7 -24.4 7.09
975 1477 678 -294.7 -260.4 -25.5 7.42
1000 1448 651 -315.5 -280.3 -26.8 7.78

</pre><hr />
 

royinidaho

Well-Known Member
Joined
Jan 20, 2004
Messages
8,950
Location
Blackfoot, Idaho
Here ya go Grit....

Here's what you posted:
332Grit_s-Numbers.jpg


Here's the drop chart. The numbers track real well with your numbers.

You have no email address on your bio or I would have sent the spread sheet.

I keep things pretty simple. When you ground truth the chart you'll be ready to go.

Keep in mind that it is good for only the elevation, humidity, barometric pressure, up or down angle you were shooting and, the way you were holding your mouth the day you charted the numbers. /ubbthreads/images/graemlins/grin.gif

Sorry for the smallitity (new word I just invented), kind of hard on the eyes but is the best I can do in the time I had.:(

Also no quality control applied. Verify all number. Not responsible for any misses you make. Though, will take credit for any hits.;)
332Grit_s-Drop-Chart_1-med.jpg
 

grit

Well-Known Member
Joined
Mar 23, 2005
Messages
1,375
Location
Utah
[ QUOTE ]
Gosh, this site sure has a helpful bunch of guys.

[/ QUOTE ]
Len's right. You guys are fantastic!

Roy, I updated my profile to include an e mail. Please send me the spreadsheet. [email protected]

About the bc: The bc I was putting in the program (eskimo.com something, from this forum) is the one listed on the hornady website (what's it based on?). Adjusted bc?? The bc changes with altitude and velocity? How do I figure an accurate bc to plug into the programs?

Thanks gentlemen!!

I just realized I made a mistake. Let me clarify a couple things.

I realized I stated a five degree cant on my initial post. What I meant was I shot at a five degree inclination. What I want to do is get a match on a ballistics program I can save and vary as necessary. I don't know how much difference a five degree inclination makes.
 

James H

Well-Known Member
Joined
Jan 15, 2006
Messages
505
Location
Nebraska
Dave KIng

[ QUOTE ]
This is close although it may be of no value. You'd need to check your 100 yard zero and some of the other intermediate ranges.



Velocity (fps)......3060
Bullet Weight (gr)..140
Bullet BC..............0.430
Start Distance......0
Range Increment...25
Altitude (ft)........4000
Temperature (F)....55
Scope Height (inch).1.75
Mil Value (3.44, 3.6).....3.440
MOA value (1.0, 1.047)..1.047
Zero Range (yds)........100


<font class="small">Code:</font><hr /><pre>
Range Vely Energy Total Bullet MOA Mil
yds fps ft/lbs Drop Path Drop Drop
0 3060 2910 0.0 -1.8 0.0 0.00
25 3010 2816 -0.1 -0.9 -3.6 1.05
50 2961 2725 -0.5 -0.4 -0.7 0.21
75 2912 2635 -1.1 -0.1 -0.1 0.02
100 2864 2549 -1.9 0.0 0.0 0.00
125 2817 2466 -3.1 -0.2 -0.1 0.04
150 2770 2385 -4.5 -0.7 -0.4 0.12
175 2723 2304 -6.2 -1.5 -0.8 0.23
200 2677 2227 -8.2 -2.5 -1.2 0.35
225 2632 2153 -10.4 -3.9 -1.6 0.48
250 2587 2080 -13.0 -5.5 -2.1 0.61
275 2542 2008 -16.0 -7.5 -2.6 0.76
300 2498 1939 -19.2 -9.8 -3.1 0.91
325 2454 1871 -22.8 -12.5 -3.7 1.07
350 2411 1806 -26.7 -15.5 -4.2 1.23
375 2368 1742 -31.0 -18.9 -4.8 1.40
400 2326 1681 -35.7 -22.7 -5.4 1.58
425 2284 1621 -40.9 -26.9 -6.1 1.76
450 2242 1562 -46.5 -31.6 -6.7 1.95
475 2201 1505 -52.5 -36.7 -7.4 2.15
500 2161 1451 -58.8 -42.1 -8.0 2.34
525 2120 1397 -65.9 -48.2 -8.8 2.55
550 2080 1344 -73.2 -54.7 -9.5 2.76
575 2041 1294 -81.0 -61.5 -10.2 2.97
600 2002 1245 -89.2 -68.8 -11.0 3.18
625 1963 1197 -98.1 -76.7 -11.7 3.41
650 1925 1151 -107.5 -85.2 -12.5 3.64
675 1887 1106 -117.5 -94.4 -13.4 3.88
700 1850 1063 -128.2 -104.1 -14.2 4.13
725 1813 1021 -139.8 -114.7 -15.1 4.39
750 1777 981 -151.9 -126.0 -16.0 4.66
775 1742 943 -164.7 -137.8 -17.0 4.94
800 1707 905 -178.3 -150.5 -18.0 5.22
825 1673 870 -192.5 -163.8 -19.0 5.51
850 1639 835 -207.7 -178.1 -20.0 5.82
875 1606 801 -223.4 -192.9 -21.1 6.12
900 1573 769 -240.1 -208.6 -22.1 6.44
925 1540 737 -257.9 -225.4 -23.3 6.77
950 1508 706 -276.1 -242.7 -24.4 7.09
975 1477 678 -294.7 -260.4 -25.5 7.42
1000 1448 651 -315.5 -280.3 -26.8 7.78

</pre><hr />

[/ QUOTE ]

Dave do you have a terminal ballistics program that calculates the drop in mils or did you do as I and calculat them from info from your ballistics program.
If your ballistics program does, what are you using?
 

royinidaho

Well-Known Member
Joined
Jan 20, 2004
Messages
8,950
Location
Blackfoot, Idaho
Len
Yep, there are.... But on the other hand /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

Grit,
The program that Dave posted the results from, takes care of changing BC with environmental conditions. You enter all of the info, barometric pressure, temp, etc and it takes it all into account.

That's why I said that what I posted is good for the conditions under which you shot. Recall I said all you wanted was a "bonk".

With the program that Dave used, calcuate once, then enter the values for the day you are shooting, whenever it is, and you get a 'bonk' every time.

Me thinks that Dave gets a 'bonk' about every shot. Unless he forgets which bbl he has screwed on the action. /ubbthreads/images/graemlins/grin.gif

Regarding you 'cant'.

Angle is 5 degrees. Cosine of 5 degrees is .996

1000 yds * .996 = 996 yds. So at 1000 yds you hold for 996 w/a 5 degree up or down angle.

I'm not into the click thing quite yet, using a mil dot so I just nudge up/down as necessary.

There's a thing on that eskimo.com site that does all of the above for you.
 

Recent Posts

Top