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
Rifles, Bullets, Barrels & Ballistics
Need some help extrapolating my drop data.
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="royinidaho" data-source="post: 373429" data-attributes="member: 2011"><p>Oliver,</p><p></p><p>Me thinks something is goofy........</p><p></p><p>Here's what I came up with entering your real world drops:</p><p></p><p>-------------------------My --------------Exbal.</p><p>-------------------------Exbal----------- Adj.</p><p>------------------------ Run----Diff------Drops</p><p>100yrds -- 0 moa ----0--------0--------0</p><p>200yrds -- 2 moa-----1.25----+.75----1</p><p>250yrds -- 2.75 moa--2.25----+.5-----2</p><p>300yrds -- 3.5 moa---3.50-----0-------3</p><p>370yrds -- 5.75 moa--5.25-----+.5----4.5</p><p>400yrds -- 6 moa------6.0------0-------5.25</p><p></p><p>Reaffirmation of the 200/250 and 370 yard data may be needed????</p><p></p><p>Adjustments (I've only done this for real twice for my 270 AM and 338 RUM thus a grain of salt is appropriate) But both are spot on the 338 to 900 and the AM to 1400.</p><p></p><p>Here we go.</p><p></p><p>Lets either drop the 200 yd data as the 250 and 300 agree. However the the data at 300 and 400 conflicts w/the 600 drop.</p><p></p><p>Now we're stuck.......Exbal wants to know the sight adjustment made for each distance beyond the zero distance. I'm gonna assume that hold over was used as I don't know of many scopes w/mil dots and mil turrets. If that is the case the inconsistencies in the drops may be due to interpolation between mil dots, especially if the reticle is a mil between the dots with no hash marks for 1/2 mil.</p><p></p><p>You may have held zero for all shots and logged the drops below the Point of Aim. Thus there are no adjustment to enter into Exbal......... (Just a Note: when doing this you'll find that your drops are off by the cosine of gravity.<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /> I attended a lecture about that one time. Have no idea of how much it is but for me I'm confident its negligible. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite8" alt=":D" title="Big Grin :D" loading="lazy" data-shortname=":D" />)</p><p></p><p>I'm confident that if these data are entered into excel it will be tough to get R^2 to 1 or at least 5 - 9s. Also I think that if excel were used and the curve adjusted, by dragging the inconsistent points you'll come pretty close to Exbal but with either reaffirmation of the drops will be necessary.</p><p></p><p>I entered the Exbal run drops as "Sight Adj Used" then entered the differences in drops at 200, 250and 370. I also included 300 with a +/- MOA of 0.0.</p><p></p><p>Exbal said the average MOA adjustment was -0.43 MOA and calculated the velocity to be 3000. (The velocity adjustment is the way that Exbal compensates rather than adjust the BC. I think......)</p><p></p><p>Hopefully someone w/more experience w/exbal will chime in. I've been doing things with excel for years with pretty great success but like code such as exbal much better (except for the velocity adjustment thing.)</p><p></p><p>HTH</p><p></p><p>Roy</p></blockquote><p></p>
[QUOTE="royinidaho, post: 373429, member: 2011"] Oliver, Me thinks something is goofy........ Here's what I came up with entering your real world drops: -------------------------My --------------Exbal. -------------------------Exbal----------- Adj. ------------------------ Run----Diff------Drops 100yrds -- 0 moa ----0--------0--------0 200yrds -- 2 moa-----1.25----+.75----1 250yrds -- 2.75 moa--2.25----+.5-----2 300yrds -- 3.5 moa---3.50-----0-------3 370yrds -- 5.75 moa--5.25-----+.5----4.5 400yrds -- 6 moa------6.0------0-------5.25 Reaffirmation of the 200/250 and 370 yard data may be needed???? Adjustments (I've only done this for real twice for my 270 AM and 338 RUM thus a grain of salt is appropriate) But both are spot on the 338 to 900 and the AM to 1400. Here we go. Lets either drop the 200 yd data as the 250 and 300 agree. However the the data at 300 and 400 conflicts w/the 600 drop. Now we're stuck.......Exbal wants to know the sight adjustment made for each distance beyond the zero distance. I'm gonna assume that hold over was used as I don't know of many scopes w/mil dots and mil turrets. If that is the case the inconsistencies in the drops may be due to interpolation between mil dots, especially if the reticle is a mil between the dots with no hash marks for 1/2 mil. You may have held zero for all shots and logged the drops below the Point of Aim. Thus there are no adjustment to enter into Exbal......... (Just a Note: when doing this you'll find that your drops are off by the cosine of gravity.:) I attended a lecture about that one time. Have no idea of how much it is but for me I'm confident its negligible. :D) I'm confident that if these data are entered into excel it will be tough to get R^2 to 1 or at least 5 - 9s. Also I think that if excel were used and the curve adjusted, by dragging the inconsistent points you'll come pretty close to Exbal but with either reaffirmation of the drops will be necessary. I entered the Exbal run drops as "Sight Adj Used" then entered the differences in drops at 200, 250and 370. I also included 300 with a +/- MOA of 0.0. Exbal said the average MOA adjustment was -0.43 MOA and calculated the velocity to be 3000. (The velocity adjustment is the way that Exbal compensates rather than adjust the BC. I think......) Hopefully someone w/more experience w/exbal will chime in. I've been doing things with excel for years with pretty great success but like code such as exbal much better (except for the velocity adjustment thing.) HTH Roy [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Need some help extrapolating my drop data.
Top