BC for Federal Fusion

[ndking1126]

Not sure if this is the best place to ask, but I've noticed that Federal lists the loaded Federal Fusion 270 Win 130 grain bullet with a BC of .4 G1, but the bullet-only 130 grain .277 Fusion bullet is listed as .367 G1.

Is this because the bullets are somehow different or an error on their website? If an error, do you know which one is accurate? I've e-mailed Federal the same question, but they don't respond.

Thank you!

 

[Unclenick]

Could be the 0.4 number is for muzzle velocity and 0.367 is an average over a range of likely muzzle-to-impact velocities. Unless a bullet has the same nose shape and flat base as the G1 reference projectile, a single BC number with respect to that reference projectile won't hold up at all velocities.

That said, if you have a scope 1.5" above the bore line and you zero at 200 yards, at the 3050 fps claimed velocity for this cartridge, the difference in point of impact for a G1 of 0.400 or 0.367 that did stay constant is only about an inch at 400 yards, and 4 inches at 600 yards. You have to be shooting some distance for it to matter a lot.

Output Trace from QuickTARGET unlimited with permission from Ed Dillon at NECO to use the occasional output from the QuickLOAD-related programs.

 

[jmr40]

Not enough difference to matter.

BC changes with velocity. Just a guess, but the .400 BC is probably accurate with the factory load. Since they don't know the actual velocity bullets used in handloads will achieve the .367 may just be an average they came up with.

 

[ndking1126]

I like the way you two think. Thanks for chiming in.

I know that the BC is lower when the velocity is lower, so I'm a little disappointed in myself for not even considering the possibility, lol. It's all good, though.

 

[Unclenick]

One of the things Bryan Litz wrote that got my attention was that even within one box of match bullets, BC can vary 3%. It's marketing thinking that gets folks caught up in the whole business of worrying over small BC differences. If you want to improve your shooting, figure a match shooter will gain the occasional point from a 10% BC improvement, while the average shooter will need a 20% increase to begin to affect his sight settings enough to matter in most instances, and that will still only be at 400 yards and out. For example, if you were talking a 0.367 vs a 0.44, then you would be looking at a couple of MOA change in hold at 400 yards and enough drop difference to walk you out of the best deer kill zone. 10% isn't normally enough to change bullets over.