Heebes,
My dive partner and I use the same breakaway setup. All we do is use a small section of light bungee or even a thick hair rubber band (the kind that comes in different colors) and tie it in a loop. We go ahead and rig our shooting line the usual two wraps but also give an extra half wrap so the shooting line extends almost down to the line release. Don't tie off to the line post/hole in the front of the gun. We attach the bungee/rubber band to the end of the shooting line and loop the bungee over the line release. Make sure that the bungee keeps the shooting line tight but not to the point that the stretch of the bungee is maxed out. The float line is then clipped directly to the loop in the shooting line and not to the bungee. This has proved to be a very simple, cheap, and effective setup for both reef and blue water applications. I'm not sure what kind of gun you are shooting but this should work for an Alexander/Riffe line release or even the alligator clip. One thing to remember, once you shoot, the gun is no longer attached to anything so you need to remember to sling up your gun. I had a dive partner use this setup, forget he was shooting a breakaway and clip his float line to his gun. He went ahead and shot a small snapper which quickly ran down the ledge with his shaft unattached to anything else. He started surfacing with this totally confused look on his face. Luckily his line got tangled on a coral head in 70 feet so we got his shaft back. Later in the dive, he clips his float line to the breakaway. He shoots a small grouper and surfaces leaving the fish on the bottom. Feeling kind of sea sick, he flips over onto his back and starts throwing up. When he finishes, he looks for his gun thinking it is attached to the float line. Wrong! His gun has drifted away. We spent a fair amount of time running up and down the coast in the zodiac but couldn't find it. Sling your gun! This also comes in handy when the sharks show up while your still fighting your fish. At least you got a stick and not just your hands. Hope this helps.l
Brad :martial