Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Rifles, Reloading, Optics, Equipment
Long Range Scopes and Other Optics
How accurate are angle cosine indicators?
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="Brent" data-source="post: 17449" data-attributes="member: 99"><p>Darryl,</p><p></p><p>I appreciate that whole picture explaination of your success with it, makes sense. <img src="http://images/icons/smile.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /> </p><p></p><p>I'll keep my range limited to what I feel sure of, and that's still under 1000 yards by a ways. Keeping POI within 8" of POA every shot is still my personal range limitation test. This gives me a little wiggle room on a moose, with the wind being by far the worst variable, range determination will definitely come into the picture as the range increases.</p><p></p><p></p><p>The M43 relies on a laptop to work, so does PressureTrace. The tests are saved and then printed at home on the printer here, although you could bring a printer along with you too. It's too easy to replay the test on the computer if I need to see it at the range tho. </p><p></p><p>The computer and strain gage leads are hooked to the M43, sky screens too if you're measuring MV or down range velocity, which I usually do as well. The computer is plugged into the DC charger and into the cigar lighter socket in the truck, or into the battery booster pack I bring along. </p><p></p><p>If we're in the field testing and not at the local range, the computer sets on the truck seat next to the bench, with the on the bench.</p><p></p><p>I use a PDA with Exbal for my drops when shooting LR. The Kestrel graphs the wind speed at the muzzle in 2 second intervals. The predominant condition and its duration is identified and then used as a referance.</p><p></p><p></p><p>* * * </p><p></p><p></p><p>After doing a little checking, I found if you multiply the total bullet drop from the muzzle by the cosine of the angle, which the ACI will give you, you will indeed end up with the exact solution predicted by the programs with that angle entered in. </p><p></p><p>Take the example given in the Sierra handgun manual for instance:</p><p></p><p>44 Mag</p><p>240gr JHC</p><p>1400 fps</p><p>.186 BC</p><p>Standard conditions at 5000 ft:</p><p>Temp = 41.2</p><p>BP = 24.52</p><p>Hum = 78</p><p>Adjusted BC = .2159</p><p></p><p>Sight height = 1.2</p><p>Impact range = 500 yards</p><p>Incline angle = 60 degrees (cosine .500)</p><p></p><p>Drop = 375.56" or 71.72 MOA = (375.56 * 1.047 / 5)</p><p>Path = 35.86 MOA = (71.72 * cosine of .500)</p><p></p><p></p><p>Path on program = 35.86 MOA also, so this is indeed the formula they use. At least that's explained now. <img src="http://images/icons/smile.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p></blockquote><p></p>
[QUOTE="Brent, post: 17449, member: 99"] Darryl, I appreciate that whole picture explaination of your success with it, makes sense. [img]images/icons/smile.gif[/img] I'll keep my range limited to what I feel sure of, and that's still under 1000 yards by a ways. Keeping POI within 8" of POA every shot is still my personal range limitation test. This gives me a little wiggle room on a moose, with the wind being by far the worst variable, range determination will definitely come into the picture as the range increases. The M43 relies on a laptop to work, so does PressureTrace. The tests are saved and then printed at home on the printer here, although you could bring a printer along with you too. It's too easy to replay the test on the computer if I need to see it at the range tho. The computer and strain gage leads are hooked to the M43, sky screens too if you're measuring MV or down range velocity, which I usually do as well. The computer is plugged into the DC charger and into the cigar lighter socket in the truck, or into the battery booster pack I bring along. If we're in the field testing and not at the local range, the computer sets on the truck seat next to the bench, with the on the bench. I use a PDA with Exbal for my drops when shooting LR. The Kestrel graphs the wind speed at the muzzle in 2 second intervals. The predominant condition and its duration is identified and then used as a referance. * * * After doing a little checking, I found if you multiply the total bullet drop from the muzzle by the cosine of the angle, which the ACI will give you, you will indeed end up with the exact solution predicted by the programs with that angle entered in. Take the example given in the Sierra handgun manual for instance: 44 Mag 240gr JHC 1400 fps .186 BC Standard conditions at 5000 ft: Temp = 41.2 BP = 24.52 Hum = 78 Adjusted BC = .2159 Sight height = 1.2 Impact range = 500 yards Incline angle = 60 degrees (cosine .500) Drop = 375.56" or 71.72 MOA = (375.56 * 1.047 / 5) Path = 35.86 MOA = (71.72 * cosine of .500) Path on program = 35.86 MOA also, so this is indeed the formula they use. At least that's explained now. [img]images/icons/smile.gif[/img] [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Long Range Scopes and Other Optics
How accurate are angle cosine indicators?
Top