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
Drag Function question.
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="jeffjackson" data-source="post: 287579" data-attributes="member: 14728"><p>Nathan,</p><p> </p><p>For those distances/cartridges I would not expect different drag curves to produce significantly different results.</p><p> </p><p>For instance, here are some results of one of my 6.5x284 loads, comparing</p><p>1. Using Sierra provided multiple G1 BC/velocity values</p><p>2. Using just top Sierra G1 BC value (0.595)</p><p>3. Using top Sierra G1 BC value converted to G5 BC with G5 drag curve</p><p>4. Using top Sierra G1 BC value converted to G7 BC with G7 drag curve</p><p> </p><p>2775 fps Sierra 142gr MK, sight Height 1.8. ICAO standard conditions.</p><p> </p><p>This is generated with some software I wrote, but you could easily compare with any of the other packages out there.</p><p> </p><p><span style="font-family: 'Fixedsys'">Drop (in) 600 yd 1000 yd</span></p><p><span style="font-family: 'Fixedsys'">1. Multi-G1 -82.2 -322.3</span></p><p><span style="font-family: 'Fixedsys'">2. G1 -81.4 -314.7</span></p><p><span style="font-family: 'Fixedsys'">3. G5 -82.0 -321.5</span></p><p><span style="font-family: 'Fixedsys'">4. G7 -81.5 -316.2</span></p><p> </p><p>I would suggest using the Sierra multi-BC values where you have them with the G1 curve. If you have a vendor supplied or measured BC for another drag curve then use that. Converting a G1 BC to another drag curve is just another place to introduce some error, since most of the time you don't know the velocity range over which the G1 was calculated.</p><p> </p><p>Jeff</p></blockquote><p></p>
[QUOTE="jeffjackson, post: 287579, member: 14728"] Nathan, For those distances/cartridges I would not expect different drag curves to produce significantly different results. For instance, here are some results of one of my 6.5x284 loads, comparing 1. Using Sierra provided multiple G1 BC/velocity values 2. Using just top Sierra G1 BC value (0.595) 3. Using top Sierra G1 BC value converted to G5 BC with G5 drag curve 4. Using top Sierra G1 BC value converted to G7 BC with G7 drag curve 2775 fps Sierra 142gr MK, sight Height 1.8. ICAO standard conditions. This is generated with some software I wrote, but you could easily compare with any of the other packages out there. [FONT=Fixedsys]Drop (in) 600 yd 1000 yd[/FONT] [FONT=Fixedsys]1. Multi-G1 -82.2 -322.3[/FONT] [FONT=Fixedsys]2. G1 -81.4 -314.7[/FONT] [FONT=Fixedsys]3. G5 -82.0 -321.5[/FONT] [FONT=Fixedsys]4. G7 -81.5 -316.2[/FONT] I would suggest using the Sierra multi-BC values where you have them with the G1 curve. If you have a vendor supplied or measured BC for another drag curve then use that. Converting a G1 BC to another drag curve is just another place to introduce some error, since most of the time you don't know the velocity range over which the G1 was calculated. Jeff [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Drag Function question.
Top