Railgun Shooting high

[shaneshac]

I have just put a JBL rail on my 90 cm eurogun. I have not changed anything else. The rail is on completely straight, but for some reason it shoots really high. I have a 140 cm long shaft which in theory should cause it to shoot low as it was shooting OK with no rail or shaft guide.

Any suggestions???

 

[Amphibious]

A little more info:

Shooting high at what range?

what are you using for bands?

Shaft thickness?

is your rail the proper hight?

 

[shaneshac]

I use this gun for cave and reef hunting and generally do not shoot longer than 3 meters.

THe gun is an Cress- sub Apache 90. I am using 22 cm long 20mm bands. As powerful as it gets with single bands!

THe rail height looks OK. THe shaft sits properly in the muzzle and the rail does not interfere with the trigger release.

I was missing real close range shots. I shot a bream (big round fish) at 1 metre from the tip and aimed at the centre of its body. The spear trimmed its dorsal fin.

Hope this info helps

 

[shaneshac]

Sorry forgot to mention I am using a 140 cm 6.5mm shaft with single flopper on top.

 

[Abriapnea]

OK , everyone here will vouch that I am no great guru on things even remotely tech , but personally I prefer my spears to only just protrude from the gun ; no overhang .
Maybe try a shorter spear ?

 

[shaneshac]

Hi Abri,

The word on the street is that a longer overhang should cause a lower shot.

I'll try your tactics and see if they work. If not I'll just pull the rail off and keep the gun as it was.

I have just got a new Picasso Century Carbon 110 Got any info on these guns. Do I keep it standard or should I also fit a rail.

Had it exchanged for my Omer Alluminum as the Omer's have been called back by the factory due to corrosion.

Thanks again.

I'll let you know how your technical advice went

P.S. You should come over to Gibraltar. Monster Bluefin of over 400 kilos have started to come in. Need to get myself a gun for those beasts.

 

[Murat]

Originally posted by shaneshac

P.S. You should come over to Gibraltar. Monster Bluefin of over 400 kilos have started to come in. Need to get myself a gun for those beasts.

Hey shaneshac,

Let few of those monsters to pass through, maybe one of them decide to come Cyprus. I am just wondering how it feels to see 400 kilos of fish underwater

 

[shaneshac]

Put it this way.

Every time one of these things approaches, the water turns a murky brown

Got more frightened by the 2.5 metre mako shark that swam past me a couple of weeks ago.

Have you seen the Tuna guns made by Totem sub. Look as though they would be able to handle one of those brutes.

Last year a spanish guy was breathing up on the surface when a 300 kilo tuna swam underneath him. With his 100cm gun he ducked his head under and stoned the fish with a brain shot.

THe fish started sinking and nearly took the spearo down with him. They managed to boat it and then sold the fish for 4000 Euros to a Japanese boat. Not bad eh!!!

 

[ivan]

hi Shane

Like Abri my Railguns also have 10cm shorter spears then standard however I remember reading on the www.spearfishing.com.au forum about a guy with the same problem and he was told that it was something to do with how he was holding the handle which can turn the guns accuracy :hmm, but if you were already shooting straight before the only thing I can think of is that maybe those short 20mm bands are slightly whipping that small and short 6.5mm shaft, iy has happened to me before when putting a strong 20mm on a 6.5.

cheers

 

[Murat]

Originally posted by shaneshac
Put it this way.

Got more frightened by the 2.5 metre mako shark that swam past me a couple of weeks ago.

Have you seen the Tuna guns made by Totem sub. Look as though they would be able to handle one of those brutes.

Last year a spanish guy was breathing up on the surface when a 300 kilo tuna swam underneath him. With his 100cm gun he ducked his head under and stoned the fish with a brain shot.

THe fish started sinking and nearly took the spearo down with him. They managed to boat it and then sold the fish for 4000 Euros to a Japanese boat. Not bad eh!!!

Damn ! ! ! He landed 300 kg = 660 lbs Isn't this bigger than Paulo Gaspar's tuna?????
Did he aware that he landed possible world Record??? With 100 cm euro, Brain Shot

I didn't see shark yet but hope too see one. It scary for me but you have to face aginst it somewhere if you want to be good spero :waterwork

I sold my gun, my first choice was Totemsub but they are too expensive. 280 euro +150 shipping + Duty + Tax = more expensive than Riffe. I can't i magine how much will be the tuna gun. But if you have dealer there its just cool. You can get one for those tunas. I have to find something cheaper. Now i am looking somewhere else for new gun.

 

[fuzz]

Originally posted by ivan
I remember reading on the www.spearfishing.com.au forum about a guy with the same problem and he was told that it was something to do with how he was holding the handle which can turn the guns accuracy :hmm,

Explain please :hmm

 

[ivan]

hi

Fuzz I'll do some searching tonight and see if I can find that thread and be more specific

cheers

 

[Griff]

This chap at the dive factory was telling me how people often complain about missing when they first us a railgun. he says its because you aim differently. i couldnt tell you because my first gun was a railgun, but maybe if you drop Rob a line he'll be able to explain it better.

 

[Murat]

I read this in Adrenaline,

If the proble is your aim, this is worth to try....

"Many divers have problems at first because the railgun is so different. When you are accustomed to aiming and using equipment that performs a certain way then change will feel strange and may take a while to get used to. Before getting further in this subject, let us try to visualize two geometric concepts, most important for a better understanding. 1) Horizontal plane: lean down at the head of a long table until your eyes level with the tabletop. Now everything you see on the tabletop, or along it, is in the same horizontal plane of your eyes. 2) Vertical plane: lean one ear against a long wall. Everything you see along or up and down the wall surface, like a picture, is in the same vertical plane of your eyes. That understood, be aware that the main problem area seems to be in the way some divers aim. Most look over the top of their guns while aiming, bringing the gun up onto the target. This tends to make it accurate in the horizontal plane because of the way you are looking over the gun, but not so in the vertical plane. We have found the best way to aim a railgun or any gun for that matter, is to not aim over the top, but rather along the side of the gun. What this does is it helps you to keep it very accurate in the vertical plane, which is much more important than the horizontal because most fish are much longer than they are wide. This is especially true with open water game fish that are difficult to get close to. When looking along the side of the gun, the rubbers, barrel and spear are all in the same [horizontal] plane as your eyes. All you have to do now is lift or lower the whole gun until it is on the same plane with the fish's spine. When this is in line, then the gun is moved from side to side to control the horizontal plane while keeping it in line with the spine vertically. In this way the shot will be on target with the spine but maybe a little out regarding the lateral placement. This lateral, hence horizontal, inaccuracy is not as important considering the spine is as long as the fish is. "

 

[poacher]

Shane
Your gun may be shooting different than before
but if it used to hit where you wanted why did you modify it?
maybe you just need to try some target practice with your gun in calm water and adjust the way you aim untill yu start to hit the target consistantly if the gun is shooting in the same place everytime you only need to change your aiming or sight picture -try looking flatter along the spear when you shoot or aiming a little low a bit of practice and after a few hits you should program yourself to adjust to the right picture to hit without thinking.
regards peter

 

[Abriapnea]

Shaneshac ; you line me up a job with a PADI/SSI/IANTD dive center (must have free internet) , and I am there ...

Tambien hablo Hollandes y un poco de Alleman .

 

[Spearooo]

true that
target practice and maybe a thicker spear.
It would take some b@lls to shot a bluefin with a 100cm single band id like to see a pic of that one. id probably pass unless he was moving at 1 mph and 1meter away. maybe then.

 

[poacher]

Shaneshac
Another thing you could try to make your gun shhot lower is to put an extension onto your front sight of your gun or the top of the spearguide on the muzzle this will make it appear higher therfore you will point the spear lower to aim sight at same place try aout 10mm increase here and see what difference it makes to your shooting.
Regarsd Peter