Double Bands - length/diameter

[Jonny250]

I'm about to order a new Omer gun (HF2) and want to fit a second (circular) band; I cant find any info in the Omer spec's on recommended band length/diameter - any ideas?
For example, if i changed the single 18mm band for 2 x 16mm, which length should i fit for the upper and lower bands?
also, if i buy the band tube and cut it to length, how do i fit the wishbone to it?
Any advice appreciated... Thanks.

[Marwan]

johny
how long is the gun?
i have the HF2 110, still didnt get to try it, it might be good with 2x16mm bands...i decided to leave it with one band for the time being though and try out the original setup with 18mm bands and a 6.5mm spear,
i have a rabitech 110 with twin 16s and 6.75mm spear and it is great. so i firgured id leave the HF2 with the original setup to compare and see what suits me more...the rabitech has an open muzzle for 2x16mms the HF2 doesnt , so im not too excited about using it with twin bands,,i think il leave it as is...did you try it out with the original setup?
let us knw the length of the gun to help u out...

[Jonny250]

Thanks for the reply Marwan, i am looking at just the 90cm gun, although a 110 is tempting... I havent made the order yet...
interestingly I looked at the rabitech guns too, very nice, and Eric was very helpful with info etc, but the shipping cost is huge.
I'd certainly be interested to hear your thoughts on the comparison of the 2 guns.
Interesting comment about the HF2 not having an open muzzle - i thought that it has the same as the XXV Gold - with options on muzzle configuration - is that just your chosen configuration?
One of the reasons for looking at 2 bands is for more power for less loading effort (i am a wimp!) and loading time is not an issue.

[Marwan]

the hf2 has an open muzzle but will only accomodate one circular band, the other band will be a screw in band, so im not sure i like this, with the rabitech the open muzzle allows 2 circular bands...so its a neater setup,
do you need a double band setup on a 90 gun? what are you shooting?
the omer bands are generally soft, i mean the omer 18s are quite easy to load...compared to some of the other stiffer bands like the demka for example....
i suggest you try it forst with the original setup then take it from there...

[Jobogogin]

Do any of you guys know of a way that I can get an OMER HF2 in the U.S.A. without having to pay a minimum of $80 for the shipping?

I figure that since the gun that I want is under $300, that price for the shipping is ridiculous.

[Jonny250]

Yeah, youre probably right Marwan, try the original first.. that's good advice! Thanks.
i'm just keen to get as much power into the gun as possible.
do let us know how the hf2 compares to the Rabitech.

jobo, i was quoted $160 to ship to the usa from GB so $80 sounds pretty reasonable.

[kjflyfish]

I just saw this and have a reccomendation for those wanting to make their own circular bands. There is a simple formula to get the right length:

1. Measure the band stretch, multiply this by two.

2. Subtract the length of the wishbone.

3. Divide by the amount of band stretch you want, 3.5 is optimal. This gives you a 3.5:1 stretch ratio, which equates to the band lengthening by 2.5 times it's original size. This gives a good balance of power and band life.

[kjflyfish]

Assuming 110 cm of band stretch and a 7cm wishbone:

110 x 2 = 220

220 - 7 = 213

213 / 3.5 = 60.86

So the optimum (circular) band size for a gun with 110 cm of band stretch is 60 or 61 cm, or 30 cm for screw-in bands.

[slingshaft]

Hey KJFLYFISH where can I buy 21mm sling rubber?

[kjflyfish]

By sling rubber, I'm guessing you mean for a speargun and not a Hawaiian sling. I've got 3.5 meters of blue 21mm Rob Allen rubber. If you pay for shipping and materials (box and tape), I'll ship it to ya. It's very stiff, but I'm sure it packs a hella punch. PM sent.

[Ron Bakker]

Careful about upping your power, I would recommend using it as is first then consider adjustment. I have used a 90 hf which has good range for a short gun.

[kjflyfish]

Hey Ron, I didn't know you were over here on DB too. How's the diving been up north lately? Did you see that massive 5.2 kg cray from Kapiti?

[Ron Bakker]

Na didn't see it, but it would be good in my gallery.
It has been good up here, quite a bit of snapper. Have you been using the new gun you made?

[bluewaterkiller]

Originally Posted by slingshaft

Hey KJFLYFISH where can I buy 21mm sling rubber?

i ve got some natural bulk latex rubber in 22 mm !!..was for testing those
8/10 M available in case ..was a special order to factory..
i cant load them !!ha!ha!

[kjflyfish]

Originally Posted by Ron Bakker

Na didn't see it, but it would be good in my gallery.
It has been good up here, quite a bit of snapper. Have you been using the new gun you made?

As much as possible. It's dead nuts - an absolute laser. The only problem is that I have to go all the way to Wellington to find good conditions. Hawke's Bay is pea soup.