Unlicensed Dremel
Moderator
What twist rate do you suppose is need for this Federal factory .280 Rem ammo?
Federal Trophy Copper 140s:
https://www.federalpremium.com/products/details/rifle.aspx?id=974
Seems like it's a pretty long bullet, being all-copper, but I don't see any info on twist rate there at Federal's site.
My rifle is 9.5 and I'm guessing this would need at least 9.25, 9.0, or maybe tighter.
Anyone know the bullet length?
People say these are a variation of Nosler E-Tips, and the 140 E-Tip is 1.350" long.
http://www.nosler.com/e-tip-bullet/
If that is the length, then I actually get a stability factor of around 1.48 at 3500 feet and 45 F, which is just under is acceptable, to my surprise, but in reality would be acceptable - BC would be compromised a smidge, but it should be accurate. I thought it would be way under 1.5.
http://www.bergerbullets.com/twist-rate-calculator/
But the Federal bullet has body cannelures to the E-tips smooth body, so it can't be the exact same bullet - the Federal version may be longer.
If it's 1.375" instead, for example, my stability factor drops to 1.40 at 45 F and 3500 feet, which is even with a very optimistic 2900 MV.
This bullet has a BC of .489, and would be an ideal elk bullet for me in the .280, if it shoots - don't want to shell out to buy it unless it has a high chance of shooting - I could be anywhere from 3500 to 7500 feet when hunting, and anywhere from 10 F to 45 F. So the worst case scenario is 3500 feet, 10 F, in which case stability is at best 1.37, even if it's only 1.350" long. I'd like to stay over 1.4 at least. But most likely I'd be at higher altitude.
Thanks.
Federal Trophy Copper 140s:
https://www.federalpremium.com/products/details/rifle.aspx?id=974
Seems like it's a pretty long bullet, being all-copper, but I don't see any info on twist rate there at Federal's site.
My rifle is 9.5 and I'm guessing this would need at least 9.25, 9.0, or maybe tighter.
Anyone know the bullet length?
People say these are a variation of Nosler E-Tips, and the 140 E-Tip is 1.350" long.
http://www.nosler.com/e-tip-bullet/
If that is the length, then I actually get a stability factor of around 1.48 at 3500 feet and 45 F, which is just under is acceptable, to my surprise, but in reality would be acceptable - BC would be compromised a smidge, but it should be accurate. I thought it would be way under 1.5.
http://www.bergerbullets.com/twist-rate-calculator/
But the Federal bullet has body cannelures to the E-tips smooth body, so it can't be the exact same bullet - the Federal version may be longer.
If it's 1.375" instead, for example, my stability factor drops to 1.40 at 45 F and 3500 feet, which is even with a very optimistic 2900 MV.
This bullet has a BC of .489, and would be an ideal elk bullet for me in the .280, if it shoots - don't want to shell out to buy it unless it has a high chance of shooting - I could be anywhere from 3500 to 7500 feet when hunting, and anywhere from 10 F to 45 F. So the worst case scenario is 3500 feet, 10 F, in which case stability is at best 1.37, even if it's only 1.350" long. I'd like to stay over 1.4 at least. But most likely I'd be at higher altitude.
Thanks.