What makes a good deer rifle is going out and trying different rifles and seeing what you like! Get a 700 Rem in 338 mag and shoot a deer and hit it right and the deer dies! get the same rifle in 243 and shoot a deer with it, you hit it right and the deer dies. The rifle itself is simply a means to deliver the bullet, not much more. So for me a good deer rifle needs to be one I like looking at and handling and shooting. And that is going to change depending on who's doing the looking! As for cartridge, that too is going to depend on who's doing the shooting. Some guy's seem to love high recoiling rifles other's, Like myself, don't care much for recoil. Pretty much a proven fact that the ability to kill come not from the cartridge but from how well the shooter's knows his cartridge and how to use it. Well placed shots for this cartridge or that is what kills, not bullet size. If I could only have one rifle and had to depend on that rifle for food, it would be my 22 mag. No other reason than it's a bit more effective at 100yds than a 22 long rifle! Light rifle, low recoil!
We read all the time about guy's looking for light mountain rifles and then to often want it in some super magnum so a stipulation often is it has a muzzle brake. So now you have your 6# or less rifle giving off 24# recoil that you take care of with a muzzle brake and then have to find some type of hearing protection for the one shot you hope to make! We are mostly all different in what we can handle. Kid here in town loves to shoot but all he's got to shoot is his grandfather's 30-30. He claimed shooting was no problem and recoil didn't bother him. Let him fire my 6.5x55 and he loved it, even better than grandpa's 30-30. Then let him fire a 243 and he's sold! Ask what he want's to shoot and every time it's the 243. I believe recoil sold him on that. And what could he hunt in Oregon a 243 couldn't kill very dead with a well placed bullet? Nothing! A deer killed with a well placed shot from a 338 mag is no deader than a deer killed with a well placed shot from the 243!
The OP's girl might just be one of those that recoil bother's but won't say anything for fear of not being able to shoot again. Start her out with a 243 and let her work her way up. Most likely the 243 will not bother her and going up will only serve to teach her what recoil she want's to live with. Seem's everyone forgets that! I've never shot a 260/6.5 CM but understand the recoil is very light. bet it's not as light as a 243! And lots of people say try the 308, it's not so bad. Those that say that are not 12 yr old girls either! Find someone with smaller cartridges and work your way up! Do not let her shoot something that might hurt her first. Flinch caused by recoil is learned very quickly and over come much more slowly. Best way to avoid it is to not let it in in the first place. Shoot, if it's legal start he out on a 223. A good bullet from a 223 kills just as well as a good bullet from that 338 mag, IF it's placed properly! The present #2 Grizzly bear was killed with a 22 long, yes long, by a woman that knew exactly how to use it!
