The 147 gr ELD-X is a rather long bullet.

What twist rate does your sister’s rifle have?

If it is 1-9 or slower, the bullets may not be stabilizing as well as needed for good accuracy.

A solution might come from observing that 100 grain-class monometal hunting bullets tend to anchor game just as well as 150 grain cup and core bullets like the ELD.

These may be enough shorter that better accuracy is obtained ian addition to milder recoil.