Freedivers gun questions part 2

[mishu1984]

ok. so after my question regarding the quality of freediver's guns i went ahead and bought one from my local diveshop

now it seems like an amazing gun, and every1 has given it positive reviews.
the model i bought is 130cm lenght. it was advertised as coming with 20mm bands and in my excitement, i failed to notice that the bands were infact 16mm instead of the advertised 20mm. it comes with a single notched shaft (polished notch) made of spring steel. with dyneema wishbones.

i havent had the chance to test it in the water but im fairly certain that it will be underpowered with a single 16mm band. furthermore, that single band, withouth stretching it, come half way down the barrel. now the simplest fix is to just shorten the band, the question is to what lenght? and then the really newby question is, do i measure the overall lenght of the rubber (in other words from one end to another- its a circular band) or do i measure the lenght of each side?

it seems logical that when it comes to shortening the rubber, i will only have to cut one side and re-insert the wishbone, but maybe im mistaken.

any tips, or advice will be much appreciated

 

[mishu1984]

****bump****

 

[cww180]

What size shaft did it come with a 6.6, 7, or 7.5? If it is a 6.6 then a single 16mm band will be sufficient in my opinion. If it is a 7mm shaft I would go with a single 18mm or 20mm band but a lot of people do two 16mm band on a 7mm shaft. I like a single band for faster reloading. I just made bands for my my 140cm gun and they were 31" and 29". So I'm sure that a 27 or 28" band would be sufficient. Yes just cut the constrictor knot on one side pull out the wishbone cut to proper length and re-insert and tie a double constrictor knot and you are set.

 

[Mr. X]

Hi Mishu, Are you certain they are 16mm rubbers? If the ad says 20mm & they are particularly long, I would check in case it is just the long gun making them seem smaller.

If you search the forum for something like "rubber chart" & perhaps "Rob Allen"/"Rabitech" you will find charts with recommended band lengths (the length of the entire rubber, no including wishbone) for various barrel lengths. They've been posted numerous times (Adrenaline's website usually has the Rabitech chart). Might be worth trying them at the current length before shortening, to see how you get on loading them. Loading might be more of an issue than lack of power with 130cm gun.

Look forward to hearing of your adventures with the 130cm gun.

 

[mishu1984]

CWW: it came with a 7mm shaft. for the time being i cut 2.5'' from each end of the band, thus i reduced it by a total of 5''.

Mr.X: im positive its 16mm. when i got home i took out my calipers and measure everything. i have the RA chart that shows gun lenght and suggested band length along with a step by step tutorial to tying constrictor knots. i tested the gun last nite at my friend's pool, and with a single wrap of mono the shaft droped 4 inches at the target which was well within the gun's range, and we also tested some of our other guns and they didnt drop one bit.

hopefully wednesday after classes il be able to get out and test the picasso 110 with a single 18mm and my new 130 after modifying the bands.
****note to self: cutting rubber is a bit*h***
attached is a pic of the gun previous to shortening of the bands.



[img=http://img390.imageshack.us/img390/2409/dscf0640fx0.th.jpg]

 

[cww180]

Yeah if you have a 7mm shaft then a 20mm band would be ideal an 18mm atleast.

 

[slingshaft]

Hey Mishu, which model did u buy? Was it the 'Bluewater?