I dropped some in the snow, dried them off, and shot them. Made me curious, so I also dumped a couple of my hunting loads in a bucked of water, and like you say, they shot just fine on my next outing.Because I hunt in a wet climate, I too was curious about sealing my hand loads. But about a year and a half ago, I submerged one of my 45-70 reloads in a glass of water for 2 weeks to see if it is needed. Guess what? It's not needed. That round grouped right where the rest of the 'dry' rounds went.
If you follow good reloading procedures, you should not need to seal your cartridges.
My $0.02.
James