JBL Shark Fin Shafts

Riffe, mori, etc should fit JBL fine as long as it is the squared American shaft, not euro mech.

Are you sure? I think the Kitto mech uses round shafts. I don't know if the gun he's asking about has the Kitto mech.

Post a pic of your current shaft that works with the gun.

I think the only reason that the top is squared off is to prevent the turning only the shaft in the mech. I have a few old undersee mechs that accept the standard American mech, but are made for the old Australian standard round top shafts that have the American notch cut in. Post a pic of the shaft you currently use

a riffe shaft will fit in a old jbl handle but you will have to grind off the last shark fin . the new elites will take any style 5/16" dia shaft ,and a jbl 9/32" shaft . it will also take a abbiller shaft if you cut off the last 1/4" of the tail of the shaft . guy left the top of the mech round so the mech is more versatile to what shafts you can use, and the shafts are much stronger since there is more meat above the notch on the shaft .

here is a good how to on how to modify a older jbl
Freediving and Spearfishing Technical Tips
phil

The flats on the JBL shaft tail are anti-rotation measures, whereas Riffe places a flat on top instead and squashes down the roof of the sear box. JBL have tabbed shafts for their Elite line, but the old style shaft tail may need those flats filed in. Also the rounded rear end helps reset the sear lever by pushing the sear lever backing projection fully down.

Ahh interesting. Sorry for the misguided information

Fungineer, can you post a link to your gun.

Quote from Fungineer

JBL Spearguns

The JBL Custom is a short gun, in fact my "Travel Magnum Combo" has the "Custom" as its short gun alternative without the forward barrel extension fitted. I have never used the gun in the "Custom" configuration, but the shaft length is 24" without the speartip fitted. Such a short spear is not likely to sustain big bending loads, so strength around the wishbone notches is not really going to be an issue, unless the shark fin tabs are your preference for band loading.

Fungineer, looks like you're getting into all kinds of upgrades/modifications with this gun. I suggest you leave it as is for now and get a better gun when you can. Trying to make this gun better is not going to get you anywhere.

Quote from Dan

Fungineer, looks like you're getting into all kinds of upgrades/modifications with this gun. I suggest you leave it as is for now and get a better gun when you can. Trying to make this gun better is not going to get you anywhere.

you are right dan he would be better off with a better gun ,but ,if it was me i would still modify the gun its how you learn what helps or hurts a gun and with a few tweaks and changes , that gun will shoot as good as any euro on the market (if you put 3 5/8" bands on most euros the trigger pull will jam up also and will fail quickly). as long as he dosent overload the trigger by using more than 2 bands . you cant compare a stock jbl with a 5/16" shaft with a euro with a 1/4" shaft and have a fair comparison of performance, rig then the same and performance will be dam near the same. after all a speargun is just a stick with a couple rubber bands on it that flings a stick at fish
phil

My experience has been that when doing modifications of this sort one has high hopes for the outcome. This gun will be a disappointment no matter what. Taking the time to chop up a muzzle is not a big deal, but the $75 destined for a Riffe shaft would be put to better use paying for a performing speargun, hell even a better JBL if that's what it has to be. But that's just what I'd do.

Yes I agree a speargun is just an underwater slingshot. But it's the well thought out small details that make it a pleasure or frustrating to use, and the same small details that will allow the diver to shoot and successfully land an unexpected 100lb AJ when all he intended to hunt was 3lb hogfish.

two very god posts.

i think that as lon as one's expectations are inline with reality and safety stays paramount, them one should mod and tinker away.

just dont think it will make a 36" gun shoot like a 54" one

Quote from LunkerBuster

two very god posts.

i think that as lon as one's expectations are inline with reality and safety stays paramount, them one should mod and tinker away.

just dont think it will make a 36" gun shoot like a 54" one

The "Custom" 4D33 is a 32" gun, so it really is pointless changing it. At that size it can do the job as is, gun mods are more beneficial on a gun that shoots further and can be aimed with more certainty at longer ranges.

Not for sure but looking closely at the OP maybe he was not looking to improve range or performance, but going to sharkfin/open muzzle so he could tie his own bands in the "spectra/dynema. Nothing was mentioned about improving, range etc. per se, only looking for options to make his gun more usable. It's only a thought
Bo

Quote from hydroid

Not for sure but looking closely at the OP maybe he was not looking to improve range or performance, but going to sharkfin/open muzzle so he could tie his own bands in the "spectra/dynema. Nothing was mentioned about improving, range etc. per se, only looking for options to make his gun more usable. It's only a thought
Bo

Well when and if he responds we may find out, but everyone here is pooling their knowledge and experience and he can take from it what he wants. Those wishbones will work on an ordinary shaft once the sharp edges are smoothed off, that is if there are sharp edges as we do not know how old the gun is.