[Bill McIntyre]

Here is a way to rig a breakaway with no holes in the barrel.

Size the shooting line so that the loop in the rear end of the mono or cable is a few inches from the trigger-activated line release. Stretch a loop of bungee cord from the shooting line over the line release and clip the float line to the loop in the shooting line. When you pull the trigger the shooting line and float line are released.

This set up is commonly called the Hawaiian Breakaway. Its simple, cheap, and fail-safe.