I'm looking into starting reloading. My safe is starting to fill up and I'm beginning to wonder, where do you keep all the stuff that needs to be locked up?  Right now I got my guns and my ammo in the safe, I'm not sure if I'm going to have room to keep powder in there. Buy another safe?  What do you guys who have a lot of guns, ammo, and powder do?

Lockable cabinet.

Why do you think that your ammo needs to go in the safe?

I use ammo to add additional weight to the safe.  

You probably do NOT want to keep powder in a safe.  

Containers holding powder are designed with low pressure limits in mind because the really big explosions happen when powder is ignited and the expanding gases are trapped in a tightly sealed container.  As such, the low pressure containers let the expanding gases vent out to prevent the huge blasts.  In fact if you have over a certain amount of powder the recommendation is likely to build a plywood or other wooden cabinet which can accomplish the same thing.