There are only two kinds of safety which I have had trouble with, the Greener (almost impossible to use with gloved hands) and the BRNO, which works the opposite from any other safety. As long as the safety is engaged when pushed to the rear and disengaged when pushed forward, then I can use it. With a bolt action, it has to lock the cocking piece, not the trigger.

It is a plus, if there are three positions, so the rifle can be loaded-unloaded with the safety engaged.