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Are 'side tabs' needed on gun

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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Decca

New Member
Feb 17, 2005
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I'm designing a gun that is going to be similar to the Riffe Baja. (They must have had a premonition of what I was going to do and copied it. ) Do you think that the side tabs on the front are required? Why do they use these tabs. I assume that if they were required Riffe would put them on their guns - right?

I propose to make my gun 1.3 m from the rubber attachment to muzzle to the trigger mechanism, use a 5/16 inch (8 mm) shaft with three 9/16 (16 mm) rubbers.

From what I can gather so far, the side tabs are designed to help reduce recoil and stabilise the gun. My gun will be made of jarrah and hence be heavier than the Riffe. I am relying on the weight of the gun to minimise recoil. :crutch Do people have problems with the gun this size 'kicking' ie. the front end moving up or down when the gun is fired?
 
I think alot of people refer to these as 'wings'...

Seems like quite a long gun with three bands so you might indeed get recoil that will force the gun nose up.

What I have found useful is to look at alot of gun designs carefully and try to find videos of them in action.

I am currently convinced that the high mass deisngs are the way to go. By this I mean the ones that Abellan makes (google the site if you like) these are 106cm with two bands and shoot 5m I think. Maybe you need three bands if you are shooting further and larger beasts

Anyway - I have alos added wings to a Mamba 90cm pneumatic gun - but that was for the balance rather than the recoil. For me having a properly balanced gun is very importante !

Cheers
Edward
 
The larger Riffe guns are over powered and underweight, so have a problem with recoil and muzzle rise. Many people add side stocks or muzzle wings to increase the mass of the gun and prevent muzzle rise, so Riffe finally started offering those options himself. Of course a better solution would be to have used more wood and lead ballast in the first place, but he apparently chose to make it optional if you wanted the gun to be accurate rather than change his design.

I had a Riffe Island, and it had a big recoil problem and shot very low until I added muzzle wings. Then the muzzle wings made it much more difficult to get the gun pointed where I wanted it.

If the gun has sufficient mass for the shaft and bands that it comes with (like a Wong for instance) then wings and side stocks are not necessary.
 
I agree.. it is a pain when these people make guns that are not perfect

Going back to the Maorisub Mamba 90... apparently the 110cm was the original one and is perfectly balanced. With the 90cm one they didn't balance it and the nose if very heavy. I wish I had known this before buying one Anyway I bought one - very good gun but I have had to add wings. I went for red cedar as it is light... even then I am needing bigger wings... to the point when I am thinking that maybe it isn't worth having wings on such a short and light gun. I bought it for fishing in currents and by adding wings it makes it more prone to the currents ! Vicious circle....

So wongs.... hmmm ...
 

Thanks. So recoil is a problem. Your experience indicates that recoil causes the gun to kick up. I guess that is a similar to gun recoil. Next question is how do you work out how much mass is required to reduce recoil to an acceptable level? If you use the momentum equation, what do you use as a criteria for recoil velocity.
 
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You got to wonder about the care and effort by manufacturers in designing some of this equipment.
 

I'm afraid I can't give any numbers, but can just state a few principles.

First, recoil is more of a problem if the handle is mounted low rather than behind the barrel and/or butt. All my guns are mid-handle with the handles below the wood butt. When the trigger is pulled, the bands just want to shrink, and are indifferent about pushing the shaft forward or the gun backward. If the shaft is heavy relative to the mass of the gun, then the gun gets pushed backwards. The force of the bands is above the resistance provided by your hand on the handle, so the gun rotates around the handle, the muzzle rises, and the rear of the shaft is pushed up as it leaves the gun, causing the shot to be low.

Of course Euro guns have the handle mounted more in line with the barrel, so they can generally maintain accuracy with less mass and stronger bands, but I just prefer the added maneuverability of mid handle guns.

There are basically three ways that I know of to reduce this recoil and rotation around the handle.

You can make the gun heavier.

You can use a thinner and lighter shaft.

You can use weaker bands, but of course that decreases range.

I have seen all three methods used on Riffe Islands, Riffe Blue Waters, and Riffe No Ka Ois.

Some people using the Blue Water have switched from the standard 3/8" shaft to 5/16", and I know one guy who even uses 9/32".

Some people using Islands and No Ka Ois have switched from the standard 5/16" shaft to 9/32".

Some people use longer or thinner bands than standard.

And people using all of these guns have added home-made side stocks and or muzzle wings.

I had a personal experience that demonstrated to me how a little weight can make a difference. For the first two years using a certain gun with a reel mounted on it, I could hardly miss. Then I removed the reel and started using a float line with breakaway, and started hitting low. About the same time, a friend got the same gun and used a float line from the start, and said he couldn't hit anything. Then I put the reel back on and regained my former accuracy, and my friend put a reel on and got the accuracy that he had never experienced. That convinced me that the gun was on the verge of being overpowered, and that just the weight of the reel was able to tame it.

One other example of ballast and reels. When I ordered a Wong Magnum hybrid a year or so ago, I sent Daryl Wong a 12.25 ounce reel that I planned to mount. With the standard amount of lead ballast in the gun, it sunk with the shaft out when my reel was mounted. He had to remove several ounces of lead to get the gun to float again. When you are dealing with a limited volume gun maker like Daryl who builds every gun to order, you can get it right like that. And of course if you are making your own gun, you can get it right. But there is no way a gun maker like Jay Riffe could fine tune guns like that because he has such a great volume. I'm not trying to lay blame- its just a fact of business.

BTW, I decided I didn't like the drag on that heavy reel, so I substituted one that weighted half as much. In order to keep recoil under control, I added 4 ounces of lead in the handle.
 
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Bill,

You make some good points. The examples you have given have prompted much thought. Thankyou.
 
Decca: Get yourself a physics textbook. Recoil isnt that hard to work out when you have the basic physics equations in front of you. Its hard to explain, however I'll have a go.

IF a gun was braced directly in line with the center of gravity, there would be no muzzle lift. If you lie down to shoot a rifle there is little muzzle lift, if you stand, the gun goes up! This is because the recoil force is acting on a pivot. In the case of a rifle, its the human body, in the case of a speargun its the fact that the handle is mounted BELOW the centre of gravity. So the recoil will make the speargun pivot.

The recoil is equivalent to: Mass of the shaft x the speed of the shaft.

To work out the speed of the shaft, you need to guess a little.. as acceleration is not constant.. I'll get back to you on that.

To work out the amount of mass needed at the tip of the gun to eliminate recoil lift.... hmmmm.... I need to go grab my physics textbook.. been a while since I did rotational maths..

One thing: A heavy butt end, past the handle, will actually make the muzzle lift more than a lighter butt end. Its a bit like a seesaw..
 
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Portinfer said the following:

What I have found useful is to look at alot of gun designs carefully and try to find videos of them in action.

I would be interesting in seeing any links you may have to such videos.

Shadowkiller,

I am familiar with the methods used to model the forces and motion of the gun as it is fired. It is complicated.

Recoil causes two problems. One is inaccuracy, the other is the risk of personal injury. Ideally I would like to find out a bit more about an existing gun without wings similar to the one I am going to build that does not have these problems.

As stated in the OP, my proposed gun design is as follows:

I propose to make my gun 1.3 m from the rubber attachment to muzzle to the trigger mechanism, use a 5/16 inch (8 mm) shaft with three 9/16 (16 mm) rubbers.

I would be very grateful if to hear from someone who owns a similar gun that doesn't have wings and doesn't have problems with muzzle kick and recoil.

If you have such a gun, do you have any ideas on how the problems were overcome? I would be very grateful if you tell me the gun barrel mass and spear mass.
 
The mention of videos reminds me of a very dramatic one that a friend showed me. It showed a guy using a Riffe Island to shoot a white sea bass. My friend showed me the video one frame at a time so that you could see the progress of the shaft down the gun and the movement of the gun. I believe he said that each frame represented 1/5th of a second, although I'm not sure of that.

In the first frame after the trigger was pulled, the muzzle of the gun appeared to have already risen about 6 inches. When the shaft was half way off the gun, it was bent in a huge bow over the muzzle with the rear half still being pushed up by the rising gun while the front half was being held down by water resistance. By the time the shaft was off of the gun, the muzzle seemed to be at least 12 inches higher than when the trigger was pulled.

I was not surprised to see the muzzle rising as "conventional wisdom" had told me that this was why my Island shot low, but what was remarkable to me was the big bow in the shaft before it was off of the gun. It would seem that the fact that the shaft would have to straighten itself out could not be helpful to accuracy.

I guess I should mention that before I sold my Island, I installed the muzzle wings, and whereas it had been inaccurate with three 5/8" bands before, it became accurate with even four 5/8" bands. As a side benefit, I always felt that if my boat's engine failed, I could use my gun for a paddle to get home.

But in spite of that, I didn't like the added difficulty in maneuvering he gun, so I moved on to a different brand.

BTW, the guy in the video hit the white sea bass dead center.
 
I'm getting the picture here Bill. The movements due to recoil can be significant. Thanks.
 
Sooo.
Do you guys think muzzle lift is less of a problem with a shorter gun - because the shaft is off the gun quicker?

I have an Mt0 I've been experimenting with - for maximum accuracy and range. (I have another gun too - but it is allready perfect ) I like the 0 because it fits in my fin bag - and it sinks I've noticed the Riffe MT guns have less butt behind the handle. It is also amenable to lots of different configurations.
 
how long is the mt0? from muzzle to spear notch.. just out of curiosity, my short gun is very innacurate, only really useful in holes, and only has somewhat decent punch with a 6.5 spear... i shot it freeshaft a few times, which kind of improved aim and range, but still i wouldnt consider it a gun for shooting free moving fish
 
The whole thing is only 32 inches long - so quite short. Right now it seems quite accurate with two wraps - 12 feet - with good penetration at 11.5 feet - that being for the soft fish that live around here and a 1/4 inch shaft and 5/8 and 9/16 bands (one of each). I was shooting a 38 inch 9/32 shaft but this allways felt a little heavy to me - too much recoil - and not very accurate - I think I'd have to heavy up the gun a bit to shoot that one. Seemed like I could feel the bands accelerating the shaft - whereas with this lighter one it's just 'snap!' and gone. The difficulty is with aiming - short guns are harder to aim - short mid-handles being probably the hardest - I think it actually shoot quite accurately though.
It also has an enclosed track.

The only thing I'd fault it on is the grip - I'd like to see a grip like the one on Riffe's euro series on these mid-handles - better angle and closer to the line of thrust.

Iyadiver did quite a bit of experimenting with his MT0 - I don't know if he still uses it much or not - but he was shooting really big things quite far away A search on MT0 will show up his posts.
 
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