Did you figure out what happened with your ML? I have a NEF ML that would misfire a lot until I measured the firing pin protrusion from the frame compared to another identical rifle and mine was about half. I ground some metal off the hammer face until it matched the other rifle and it has never failed to fire since.

The funny thing is that I was doing this repair job about 9:00pm the night before ML opening day. Talk about pressure.......

Yes, I found out after misfiring on 2 more bucks in Illinois later that month. It was a breech plug lube that was breaking down and moistening the 777 pellets. After the 3rd misfire I ditched the lube(it was a white colored lube, can't remember the name)and learned to barely apply future lube to threads again.