You can leave triple seven for a little while, but like all powders.. it will sooner or later start to damage the bore of your rifle. Temperature and humidity in your area will influence the rust clock a great deal. I ran a test with that powder and actually it did not start to rust a lawn mower blade for over five days. Now a lawn mower blade is not the same steel as your rifle barrel. So thatwith a grain of salt.

Its your rifle, if you want to take the chance of a couple days without cleaning between shots.. you will probably get by with it. If you are worried about rust then clean it when you shoot it. Cleaning that night or the next day is fine.

Triple Se7en is a great powder. Remember in loose form it is 15% (approx) stronger then Pyrodex RS or Goex 2f. So keep that in mind when you work your loads.. Good luck with your rifle.