Half cocked, if you leave the hammers down with the caps on you could discharge the gun. The hammers will be resting on the caps, hitting or striking the hammers would cause them to hit the caps and fire. There are gizmos you can get that go over the nipples and caps that allow you to rest the hammers without half cocking them. They also protect the caps from getting wet. Get some HotShot nipples, the caps stay on better and they reduce miss-fires. Also, the caps will fall off eventually, so in rough terrain I sometimes put my thumb over the cap to keep it on. You can also try silicone tubing, the stuff the RC airplane guys use for they're fuel systems. Slip it over the cap and nipple leaving enough room for the cap head to be exposed. This will keep the cap on and water proof it. I had to poke a Black Bear in the nose with the muzzle of my Hawkins .50 this Elk season due to a wet cap and miss-fire. Fortunately it was a young bear and ran up away after a snort. So keep yer' powder dry.