Retry ....
OK, what I've done is made a length of webbing, with knots in it about 30cm apart. The front end gets tied into the hole for the second rubber (I haven't got the heart to do this twice, so single it is) - the back of the sling gets clipped into the longline clip on the handle. Voila ....
My 100cm gun is pretty stock, 20mm rubbers, 6.5mm spear, 2 wraps of mono, rigged to a breakaway system, I use it mostly for fishing off the kelp beds in the area. I haven't taken very big fish with it, mainly because there aren't many in the kelp around here.
The 120cm gun has got a 7mm spear, also rigged to a breakaway system, but I swap the rubbers between a 20mm and a 16mm, depending on wether I need to reload quick (ie for sharks / lots of fish) or whethere I want to have a bit more kick, ie going for pelagics. I've shot my biggest fish to date with this gun, it was a 37kg Yellowfin Tuna. I've taken quite a bit of fish with this gun.
The 160cm gun has got a 7mm spear as well, 20mm rubbers, some climber's webbing that I tie to my float when I'm done loading, and, yeah, you guessed it, a breakaway system. I've taken some tough fish with this gun, including tuna, cuda, big cob, even tackled some sharks with it. It's the granddaddy of guns - bucks like a mule, and the 2.0m spear is just the ticket for just about any fish ....
The breakaway system is pretty simple, but very effective. It's includes the normal mono chord, as many wraps as you'd like, one end on the spear, the other ending in a loop. This loop should be about 15cm short of the line clip on the handle. I've got a 10cm boingie (bungee) tied into this loop, which I then hook onto the line clip. This keeps tension on the mono, so it doesn't come off the gun. The rest of the system is pretty straight forward as well, I mainly use bungee floatlines, made from latex tubing and mono with either longline clips or swivel clips on the ends. One of these lines would then be clipped to the loop in the mono (the same one as where the boingie is) and the other end clipped to a float. If I'm going deep / shooting big fish, I normally end up with three or more floats connected with bungees or normal floatline.
Finally, yes, I use the RA shafts. BUT I'll be changing that fairly soon. The main reason why I don't like the RA shafts is that the shooting line gets attached to the spear behind the wishbone notch - in other words, if you get a strong 90 degree pull on the line, al snappo .... I haven't broken one of these shafts yet, but I also don't want to lose a good fish because a spear broke ....
Whew. Typeing this stuff the second time was more work than the first time ...
Regards,
Riaan.