Semisane is right. If your going on a Bear hunt, now is not the time to change ignition. you should be thoughly familiar with your gun and it's reliability long before the hunt.
Musket caps will not provide better ignition for you, a clean-dry fire channel with CCI MAG caps or Dynimte Noble (the best!) with a proven clean dry nipple is all you need.
If confidence is the factor you need; pratice at the range with Knight's "Hot Shot" nipple and Nobel 1072 caps.
Musket caps and nipples do have a bigger hole and more fire,,,,but they also throw more garbage into the fire channel,,,gotta tell ya man,, it's about clean and dry.
p.s. take the nipple to the hardware store,,you'll find the right thread. 6x.75 is a good bet, it's either that or 6x1 or .250x28. it's a no brainer, it'll fit or not.