USUALLY... the front trigger fires the most open choked barrel (for closer flushing game)... and the back trigger fires the more tightly choked barrel (as the range to the game lengthens). This arrangement is normally what you find the most useful for upland game hunting (rabbits, pheasants, quail, grouse, partridge, etc.) as the game flushes, then flies or runs away.
However, this arrangement is the OPPOSITE of what you want when dove hunting. Usually, when dove hunting, you take a "stand" and wait for the doves to come to you. Thus, as they "come in", they are further away than they will shortly be, so you use the tightest choked barrel you have FIRST (the BACK trigger). Then as the doves fly closer and pass over or closer to the left or right, you shoot the most open choke (the front trigger).
Look at the symbols or letters at the rear end of your double's barrels and determine the choke of each barrel. Here's examples of the "codes" or 'symbols" at the breech end of the barrels if your double has fixed chokes... and their meanings.
BROWNING SUPERPOSED CHOKE SYMBOLS:
Symbol = Meaning
*** = full choke
** = modified choke
**- = Imp. Cylinder
CHARLES DALY CHOKE LETTER:
SS = Skeet #1
Strength & Honor...
Ron T.