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Rifles, Reloading, Optics, Equipment
Reloading
277 170 berger elites
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<blockquote data-quote="barefooter56" data-source="post: 1444070" data-attributes="member: 85389"><p>Just running your altitudes (2400-2700) through our twist rate calculator with the .270 170gr EOL and leaving the defaults of 2650fps , 1-10 twist rate at 59 degrees. Gives a Stability Factor ( SG) in the 1.23-1.24 range. This means that the BC of the bullet would be compromised by 8-9%. So instead of the full BC (G7) of 0.339 it would now be 0.313. A 1-9 barrel twist rate would be optimal where you hunt. What it does NOT MEAN is that the bullet would be unstable. From 0-600 yards you would see vary little difference in condition effects such as wind on the bullet from if it were at its full BC value. From 600 yards on out till the bullet hits the dirt you would see more effects on the bullet by external conditions such as wind on the bullet than if you were at full BC. you can run the numbers on the BALLISTICS CALCULATOR :<a href="http://bergerbullets.com/ballistics/" target="_blank">http://bergerbullets.com/ballistics/</a> to find just how much that would be.</p><p>The .270 170gr EOL bullet is a HYBRID bullet design that is very tolerant of jump. If you will be doing any bullet seating depth testing. I suggest that you start at .015 OFF THE LANDS. Then WORK BACK INTO THE CARTRIDGE CASE IN .005 INCREMENTS. Any bullet seating depth testing should be done at the lowest powder charge listed for the bullet/powder/cartridge combination you are testing. If you need load data please contact us at 660-460-2802 from 8am to 4:30pm EASTERN time MON thru FRI and we will be glad to help you with that or any other questions you have.</p></blockquote><p></p>
[QUOTE="barefooter56, post: 1444070, member: 85389"] Just running your altitudes (2400-2700) through our twist rate calculator with the .270 170gr EOL and leaving the defaults of 2650fps , 1-10 twist rate at 59 degrees. Gives a Stability Factor ( SG) in the 1.23-1.24 range. This means that the BC of the bullet would be compromised by 8-9%. So instead of the full BC (G7) of 0.339 it would now be 0.313. A 1-9 barrel twist rate would be optimal where you hunt. What it does NOT MEAN is that the bullet would be unstable. From 0-600 yards you would see vary little difference in condition effects such as wind on the bullet from if it were at its full BC value. From 600 yards on out till the bullet hits the dirt you would see more effects on the bullet by external conditions such as wind on the bullet than if you were at full BC. you can run the numbers on the BALLISTICS CALCULATOR :[URL]http://bergerbullets.com/ballistics/[/URL] to find just how much that would be. The .270 170gr EOL bullet is a HYBRID bullet design that is very tolerant of jump. If you will be doing any bullet seating depth testing. I suggest that you start at .015 OFF THE LANDS. Then WORK BACK INTO THE CARTRIDGE CASE IN .005 INCREMENTS. Any bullet seating depth testing should be done at the lowest powder charge listed for the bullet/powder/cartridge combination you are testing. If you need load data please contact us at 660-460-2802 from 8am to 4:30pm EASTERN time MON thru FRI and we will be glad to help you with that or any other questions you have. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Reloading
277 170 berger elites
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