Speargun ballistic

[SpearAddict]

holla companieros

I'd like to start a thread to gather information about ballistic, I mean about the interaction of bands and shaft for penetration, accuracy, range etc.
Your are more then welcome to post links of charts or other valid reference.

Let's start it with my own interrogations.

1-On a RA ZULU 1300mm with 180cm shaft, what would be the difference between 2x16mm bands or 1x20mm band. Beside the 20mm is so hard to load.

2-On the RA ZULU 1600mm and the RA ZULU 1300mm the bands are exactly the same length. What's the impact on the shaft. Can you simply cut your bands to get more power. I know it's all about balance between a few factors. I've totally overpowered a jbl explorer 20 and made the difference between catching something and catching nothing. And i can make really good headshot with it. Maybe it's cause I have it since 16 years!

3-internet sites are proposing different rubbers, but we never mention the type of rubber. It's all about diameter and length. Does somebody know if they really are better rubber than others.

4-On woody gun with a barrel of 28'' who's made for max three bands what would be the differnce between 1x20mm and 3x16mm

5-Why would you use a longer spear than original.

I really really would like your input on this. It might sounds weird that I spearfish since that long without knowing much about bands and gun.
For close than 15 years I used the jbl 20'' same mask, same tuba and same fins. no suit. I live in canada so the season is pretty short and I had never met other spearfisher before a few years ago.
I just rediscover my Passion for spearfishing 2 years ago and it became a sickness. I got geared up ,got good fish and got tons of fun.

Thanks for your help
Accuracy=less injured and more kill

 

[foxfish]

This question or similar comes up quite regularly but, speargun ballistic figures, are very hard to come by!
You would think there would be more info from the manufacturer especially considering that every type of gun you can buy will have those figures available.
Air guns, rim fire, full bore, shot guns - bows, crossbows....all have ballistics available!

 

[Bill]

If you want ball park numbers to start your experiment, try comparing the square of the rubber diameter.
for instance 2x16mm or 1x20
2x16=16x16+16x16=256+256=512
1x20= 400 or 20% less

shorter rubber gives less rubber life and more power
shorter or smaller diameter shaft gives more speed and less penetration.
when you over power the accuracy decreases

 

[SpearAddict]

This question or similar comes up quite regularly but, speargun ballistic figures, are very hard to come by!

That why i would like to gather as much info on this thread so you won't have to answer same question over and over.

Thanks

Simon

 

[Fondueset]

I did a lot of experimenting with a riffe MT0 at one point. I had a 38 inch 9/32 shaft and a 34 in 1/4 shaft. I tried all kinds of bands - the thickest was 3/4 inch - probably 20mm - then 18mm and 16mm. First - there is a formula for band length - it is intended to optimize the performance of the band - so you get the most out of it. Going shorter causes the bands to sort of 'set' - and break down.

I used the long shaft because it was more hydrodynamic than a shorter, wider shaft - and because it flew straight. My goal was to have the gun shoot effectively to about 4 meters. With the 1/4 Shaft and two 16mm bands it was effective for small fish at nearly 4 meters. With the 9/32 shaft I liked to add a third band or mix them.

My preference was for multiple smaller diameter bands because the gun shot with less recoil and felt smoother. The 20mm band felt like it almost lost energy because it snapped so hard and fast. The 18mm bands were better if I was using the larger shaft - but too snappy with the small one.

A combination of one 16 and one 18 worked pretty well for everything.

It was interesting that overpowering the gun seemed to make it less accurate. Shaft flex was not much of an issue with such short shafts, but bands that were too strong make it kick.

My conclusion was that it was best to find a balance between smooth acceleration and power and that this depended upon the weight of the shaft.

With longer guns I would think this even more critical to avoid flex and wobble.

 

[SpearAddict]

Thanks Fondueset

This post really help me
I also like two small bands than 1 big.
I didn't know we can mix band size.

By the way, do you SF in Michigan and where. Cause i do SF a lot in Quebec so it must be about the same.

 

[Fondueset]

We are very limited in what we can legally spear here - just carp and suckers.
But we have very nice waters - check out my photo site below.

 

[SpearAddict]

Dude your picture are terrific and your area look really good.We have so much beautiful lake in north america.
It sucks you can't SF at home. In Quebec it is the same permit for Lines or Speargun the only difference is we(SF) can't catch: sturgeon, maskinongé(really big pike), brown trout and salmon.