Navarro, you should absolutely heed all of the warnings you have been given about the probable mechanical issues with your rear trigger/sear mechanism. The jolt it receives upon firing the right barrel is apparently causing the left barrel to fire. This condition is commonly known as "doubling", and it is both dangerous and potentially damaging to both gun and shooter. It is only a matter of time until a lesser jolt does the same thing. The damn thing could go off from simply closing the gun sharply. Anything or anyone in front of this gun could get shot.
Fixing this issue shouldn't be very expensive. Not fixing it could get extremely costly.
