the use of "heavy for caliber bullets", especially of the round nose design, will reduce the velocity at the muzzle. Also, heavy, round nose bullets cause the bullet to shed velocity quicker after leaving the muzzle.
In other words, if you can find a 150 grain, round nose bullet for your wife's .270, that would likely be the answer, for her situation. On the other hand, the recoil would probably be increased.
You might look for some Remington "Reduced Recoil" ammo. It uses light weight bullets loaded to low muzzle velocity, essentially making her .270 more like a 30-30 velocity class shooter, and reducing recoil, as advertised. Perfectly good for close range deer. I know Remington loads Reduced Recoil for 30-06, but not sure about 270.
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