I posted this same question on a couple of other forums and everyone says the .277 130 grain works so the .308 130 grain should work as well. The thing is both the .277 and 6.5 bullets have a better BC and SD than the .308 bullet to get the similar BC and SD of the .277 caliber I have to step up to the 165 grain bullet. I just don't know if I can get 2500+ fps and still keep recoil comfortable for my daughter.
BTW, the 130 TTSX is actually longer than the 150 Hornady or Partition being all copper vs denser lead. I wouldn't worry about BC for my 12 YO daughter...and don't worry about it for the way I hunt myself since I'm not going to shoot from far enough for BC to matter....SD simply doesn't matter. Good luck.
BC and SD do still matter IMO. The bullet with the best BC is going to retain speed better even at short ranges, delivering more energy at all ranges. More energy to me means the bullet is going to work better to me by opening more violently and rapidly and creating a bigger wound.
If I have three mono bullets of the same weight and shape in 6.5, .277, and .308, the SD of the .308 bullet will be the least. I should reasonably think that it'll penetrate the least out of the three. I'm not saying I won't get an exit with the .308 bullet, just that I have a better chance with the other two. I prefer two holes in an animal, I'm not worried much about bullet recovery.
I'm really not sweating the small details as much as it might seem. I'll just let my daughter's recoil tolerance decide what she shoots, as long as the bullet shoots well. My job is to get her in position to maximize that bullets effect.
Her ability is getting better every year as to what she'll tolerate in recoil as she's getting tougher every year. Hell, she just took second place at her Rodeo Bible Camp in steer wrestling yesterday. If she'll tolerate it she may shoot my .270 or .30-06 as they are both easier to carry around all day than her M700 Classic by being a full pound lighter.
