IMO a person will never learn to be an excellent handgunner without reloading, and without a .22. You'll need both, to learn to excel.
On a separate note, regarding 300 gr. bullets, I've been known to use bigger bores than .44 and heavy bullets as well, but if deer and hogs, for example, are the size game you will hunt, a .44 240 gr. will kill any deer that ever lived. No real need for the heavies with that game. But sometimes people want what they want ....