how does this railgun setup sound?

[Marwan]

making a "bigger" gun for these one off trips...i have a rabitech apex carbon 120, deicided to install 2x16mm bands instead of the 20mm, also decided to use a slightly shorter and heavier spear. instead of 7mmX160 cm, i will use 150cm X7.5mm i think this will be a bit quickr than my standard setup and provide a bit more punch:ko ... what do you think...

 

[Dan Man]

A 160cm spear on a 120cm gun is already too short! A 170cm spear is the best size for a 120cm gun, using a 150cm spear will cause accuracy problems.

I only use a single 16mm rubber and 170cm x 7mm spear on my 120cm gun and it seems to be fit for the job

But for what you seem to want 2 x 16mm rubbers and a 7.5mm x 170cm shaft will give you a good amount of punch.

 

[Marwan]

thanks dan, it actually my mistake the shaft i already have was a 170 as you say, which i felt was maybe too long, im not the expert on railguns, but i know that part of the advantages of it is that you could use a shorter spear...why do you think there will be accuracy problems though? it cant be for spear whip as you aready have the rail and its a thicker spear...
cheers and good cobia there mate

 

[gert]

hi

two 16mm rubbers is fine but just be carfuly not to make them two strong as it tends too make the spear wip badly and you end up shooting miss

cheers gertjie

 

[Old Man Dave]

First off I must say that I am not an expert in these bigger guns for large fish but I have tested a few euro style guns to see what effect upping the power has. I also built a special test gun so i could adjust various parts to see the effect.

Because of their light mass and thin spears most euro guns quickly become inaccurate if overpowered. Personally I found that for 90cm guns a 6.5mm spear on a rail gun with a single 18mm band was the limit for accurate shooting. More power or a thinner spear gave more range but was too inaccurate. Recoil and shaft whip were the main causes. For a 20mm band you need a 7mm spear a rail, a better trigger and some luck to hit your target.

Spear overhang is a factor in accuracy. Rail guns usually use shorter spears because they are high powered. Fitting a longer spear than standard with no other changes caused a marked decrease in accuracy. This seemed to be caused by a combination of shaft whip (the % of the spear supported by the rail decreased) and recoil (the spear tip suffered an increased lever effect as it was further away).

Double bands were always a disappointment on euro guns. To make double bands work you must have more mass in the stock. Overall I would say use a single 18mm band and a 6.3 spear for long range, small fish a 6.5 spear for medium fish at range and a 20mm band with 7mm spear for big fish. Beyond that you need more mass in the stock and definitely not more mass in the spear.

That's what I think, for what it's worth.

Dave

 

[ihab]

Hi Marwan:

The setup you've just mentioned comes stock with the Tuna RA guns....so I guess you are on the right track....BTW, I'm setting up the same configuration for the same Trip...except with an added Real, 50m capacity....coincidence ??:martial

 

[Marwan]

Thanks guys, ill play around with some of the ideas here....,
Ihab, if the intention is blue water hunting, í would not recommend the reel...a big fish will strip the 50 of your reel before you could say REEL, attach a longer float line to your foam float and that would be safer in my opinion...alternatively, you could rig the gun as a breakaway system, again directly to the float (that way yu get to keep your gun)

 

[covert]

Heya Marwan i also have a rabi apex 120. Keep in mind this gun was designed to shoot larger fish. So there is by default more than enough power acuracy and range for blue water hunting. I also like it because it can have a dual function for my shore dives.

I would not shorten the spear as shorter spears (might) affect accuracy. Putting on two 16mm bands will increase the power but might flex the 7mm spear a bit also sacraficing accuracy for power. I will speak to the guys at Rabitech to see what they say, but to my mind put on 2 x 16mm bands and up the spear wheight to 7.5mm dont mess with the length though.

 

[Marwan]

Thanks covert... had a chat with louis and he sorted me out....2X16mm with an 8mmshaft x160 cm
cheers

 

[SpeerO]

Hi Marwan:

The setup you've just mentioned comes stock with the Tuna RA guns....so I guess you are on the right track....BTW, I'm setting up the same configuration for the same Trip...except with an added Real, 50m capacity....coincidence ??:martial

Hey guys... Trip?????????????? when? where? who? how? why? what?


Zane...

 

[Marwan]

hmmmm its very hush hush... ill tell you but i have to kill you later

 

[covert]

hmmmm its very hush hush... ill tell you but i have to kill you later

look on the bright side 2 x 16mm on a 8mm shaft should penetrate a human :crutch muahahhahahhaha

 

[Marwan]

Good point covert, good point