A couple thoughts; first I agree with the fellers above, if it chambers, shoot it. Also if it's just one cartridge, I'd suggest you put it in a "To Deal With Later" box and when you have more experience reloading and understand more about pressures, case capacity, etc., fix it then.
A caution about using factory ammo's powder. The factory powder is not the same powder available to us and some can be blended, at the factory, to achieve specific performance parameters. If you take the powder out of one case, and dump it in another case, that should be OK. But if you change the charge you're in uncharted territory...