TBeck, I guess I don't quite understand how this argument can work against you. It seems to me that if the situation was a legitimate case of self-defense, it would be illogical for the DA to even make that point. You just cocked the hammer to increase your accuracy, and decrease the risk to innocent bystanders, etc. Don't you want to shoot this goblin if he is about to seriously harm you or yours? That's the whole point, right? I think a shrouded hammer is a nice thing because it gives you a little extra versitility at little to no cost in concealment and presentation of the weapon.
If it is a legitimate case of self-defense, and the DA suggests you shot the guy on accident, can't you just say that you really did mean to shoot him? It's just your word against his, right? I don't see anything wrong in taking action to increase your chances of success in resisting a violent criminal. To me, It doesn't seem like that would hurt your case any. I'm no lawyer, though, that's for sure, so if I'm missing something, please enlighten me.
(edited for spelling, probably still missed stuff though)