Most of the time I hunt with a 360 to 400 grain arrow, but I have the wife setup shooting a 325 grain arrow.

Get the spine, foc, and flight right and you will have no trouble with penetration. A lot of things factor in to good penetration, and weight is only one.

She will have No trouble penetrating deer with her setup if she uses the right broadhead which is more important than arrow weight IMO.

Dan