Depends. I once left a TC Greyhawk loaded (BP) for about three months. Went bang just fine. Wouldn't try that with 777.
Recently picked up a CO2 discharger. Works like a champ, and no packed powder to dig out like is often the case with pulling a charge the old way. Gotta make sure to have a clear field of fire when you use it! Need to figure out how to get it hooked up to my Knight too.
