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
GPS and/or topo maps for ranging
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="cronhelm" data-source="post: 20698" data-attributes="member: 98"><p>I used a Garmin GPS II to measure a 1900 yd shot a few weeks ago. This was a borrowed unit so I was not familiar with all the bells and whistles but it was reasonably easy to use.</p><p></p><p>The unit showed the range in 10m increments. I do not know if it is possible to increase the sensitivity or if this is as good as it gets. </p><p></p><p>I think that 10yds is probably good enough. Conventional wisdom is that one only needs to know the range to within 25yds of the actual distance to get onto the target.</p><p></p><p>At these sorts of extreme ranges there is a lot more error in the ballistics table than there is in a GPS ranged distance. I did some reading and the G1 drag model that most ballistic computers use is not at all good at estimating drop when velocities are close to or below the speed of sound.</p><p></p><p>In my case I found that the actual drop was about 23 MOA greater than the calculated drop.</p><p></p><p>If you want to read about my 1900 yd adventure and see a few pictures go to:</p><p> <a href="http://www.nucleus.com/~cronhelm/index.html" target="_blank">http://www.nucleus.com/~cronhelm/index.html</a> </p><p></p><p>FWIW This shot was performed with a run of the mill .243 Winchester and a 1:8 barrel.</p><p></p><p>Peter Cronhelm</p></blockquote><p></p>
[QUOTE="cronhelm, post: 20698, member: 98"] I used a Garmin GPS II to measure a 1900 yd shot a few weeks ago. This was a borrowed unit so I was not familiar with all the bells and whistles but it was reasonably easy to use. The unit showed the range in 10m increments. I do not know if it is possible to increase the sensitivity or if this is as good as it gets. I think that 10yds is probably good enough. Conventional wisdom is that one only needs to know the range to within 25yds of the actual distance to get onto the target. At these sorts of extreme ranges there is a lot more error in the ballistics table than there is in a GPS ranged distance. I did some reading and the G1 drag model that most ballistic computers use is not at all good at estimating drop when velocities are close to or below the speed of sound. In my case I found that the actual drop was about 23 MOA greater than the calculated drop. If you want to read about my 1900 yd adventure and see a few pictures go to: [url="http://www.nucleus.com/~cronhelm/index.html"]http://www.nucleus.com/~cronhelm/index.html[/url] FWIW This shot was performed with a run of the mill .243 Winchester and a 1:8 barrel. Peter Cronhelm [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
GPS and/or topo maps for ranging
Top