Safety rule on batteries is, always disconnect the ground - first so if your tool or worse yet the ring on your finger touching the tool handle touches ground you do not create a circuit through the ring around your finger causing much pain and distress. Just the tool can cause sparks and battery explosion. As I remember the negative, ground or - terminal can be reached with a long phillips screwdriver after removing the seat and left side cover on my Savage.  Do make sure the lead doesn't fall back on the terminal, either secure it out of the way or wrap it with electrical tape. Then you can do whatever with the postive or + side w/o fear.  Remember the key can be removed in both the off and park lamp position. You would get a spark even on the ground side if the key is in the park lamp position as you make and break the circuit at the ground connector. Remember Sparks is BAD !!

I should have used more words....when I asked if he had removed the + first to see if that might be his problem.

And it can be spectacular when you weld something by crossing the terminals.  Was responsible for a huge bank of batteries in the Navy and every once in a while a nugget would get the DC suprise doing there first maint. on the banks.