Daryl,

you are correct that firing a inertia triggered double that has misfired on the first barrel can be achieved by giving it a smack on the butt - either with your hand or by bumping it on the ground. Be careful it's loaded - but this may be inconvenient in a charge.

Matt & 4seventy,

I forgot about the trick with the safety. You're doing more than flicking the safety back and forward you're actually bringing the safety to the rear and pushing it forward and to the right on a Browning (or double with a single selective trigger on it - some aren't selective) if I recall correctly.

Once again inconvenient in a charge but I think it would be quite "do able" if you had the presence of mind at the time.