bc copper vs lead

[rickiesrevenge]

If you have two identically shaped bullets one being made of copper (like a TSX) and a traditional cup and core bullet will the b.c. be different? If so how much?

 

[Lapua40X]

If you consider the Barnes Triple-Shock X Bullets 270 Caliber (277 Diameter) 150 Grain Hollow Point Flat Base Lead-Free and the Berger Hunting Bullets 270 Caliber (277 Diameter) 150 Grain VLD Hollow Point Boat Tail are near enough to the "same shape", then the answer is yes.
You might also want to include the Sierra GameKing Bullets 270 Caliber (277 Diameter) 150 Grain Spitzer Boat Tail on the comparison list.

 

[CatShooter]

If you have two identically shaped bullets one being made of copper (like a TSX) and a traditional cup and core bullet will the b.c. be different? If so how much?

With two bullets of the same shape, the heavier one will always have the higher BC - with lead core vs solid copper, the jacked lead cored bullet will be ~30% (+/-) higher.

 

[watercam]

The copper bullet will be longer since it is made from lighter material. One would think this would increase the BC but the Barnes bullets have never had optimal shapes to achieve high BCs. They do, however, work exceptionally well on game! The LRX bullets are closer to the length of an equivalent weight cup and core but pricey.
The Hornady GMX bullets look pretty sleek but there is not a lot of variety in weights and they are made with gilding copper. I have no experience with them so can not speak for their effectiveness on game.
I use Barnes TSX bullets exclusively for big game because they work well but I do not consider them as long range projectiles. That being said my brother shot an elk at 400 yds. with a 168 gr. TSX in 30-06 and it dropped in it's tracks. It theoretically should not have worked well at that velocity but it certainly did.
But then 400 yds. so no longer considered a long shot by the standards of some.