I have read that the 45-70s they had heated up after a few rounds and the fired shells stuck in the chambers. I belive some of the shells they recovered showed evidence of being pried out with knives.
Sounds like custer was focused on being a hero, and at the start of the battle was worried he would be outshined. He probley thought this would be the very last indian battle and it would be his last chance at being a hero again. This would make him president! This would absolve him for heat he took hanging deserters. This would outshine him for running back to illinois on a unauthorised leave. He probley thought most the indians would run in fear when they opened up on them, and certainly they could easily kill the few that stood. Take care of them, then run down and kill all the slow ones that they could all the way back to the reservation. Remember he even took a young nephew to witness the last indian battle. Seems I recall he also took a reporter too? Aint sure about that one.