The safety on the Lefever is simply a block to the triggers, operating on the blades. Wear on the upper surface of the left trigger blade could cause your problem. Another thing to check is to be sure it is coming to the proper position. Operating the opening lever pushes the safety back past safe to the rear fire position. upon closing the gun it should return to safe unless locked out by the screw. Open & close the gun & then check by feel if the safety has actually returned to it's detented position. If it should move slightly forward & then both bbls be on Safe, it probably just needs a good cleaning. I make it a habit upon loading my Lefevers to always run my thumb on the safety & make certain it set properly.
