C4 Graphite Accuracy

[Mark Laboccetta]

By the way great to see some old names on this thread at Deeper Blue, Pete hey there and Rob same to you. I thought you would have sold your Co. by now. I'm guessing COVID19 has you back on the forums Hope you guys are staying safe. Real mess here.

Hugo, let me tell you about your gun. Take it, put it on Ebay or Craigs List and sell it. I know that gun well and if in my life there is a time I nearly smashed a gun and threw it in the ocean it's that one. I generally feel that C4 is an amazing carbon fiber fin and product Co. but they "missed the mark" there. You can't fix the problems of that gun, or at least the 116.

The gun is new, 2 x 14.5 mm micro bore , 7mm shaft 7 mm.
I can’t get why it shoots so badly. I am not a newbie, 20+ experience in spearfishing...

If you want to verify the reason you are missing everything and attribute it to the gun it's simple. Lay the shaft on the track of the gun. Look at the distance or gap between the bottom of the shaft and the track. Should be none or close to none, you might see some light on the muzzle and handle ends.
Now load it somewhere you can do it safely. You'll notice a huge gap now between the shaft and the stock. It's because that gun flexes like a banana. That's why you're missing everything. The good news is it's not your fault.

The smaller sizes up to the 99 are fine, it's the longer ones that do it.

I see Pete above is showing some details of the Urukay, that gun is extremely capable and precise and incredibly well balanced and ballasted. I'll go as far as to say it's the most powerful traditional 120cm gun on the market for the simple reason you can put up to 4 14mm bands on it and it kicks ass. It's right at home with 3 bands and a 7,5mm-8mm shaft. And it's heavy so it absorbs recoil. The Graphite, not so much...

 

[Mark Laboccetta]

The rail on my Grap is pretty much flat there is no real guide and it is actually make loading more complicated because you have to guide the spear right into the handle and sometimes you have to try several times, not easy when the surface is a bit rough , or when you’re drifting in a strong currant. The only real guide I see Is at the muzzle and it’s 10 mm long.
Regarding possible overpowering, I used the recommended length of rubber from C4:
610 and 630 mm of 14.5 mm for a 120cm gun.

Overpowering/underpowering it won't matter, with sufficient power, and you need at least sufficient power it's not accurate. I shot a 200lb Bigeye tuna once with a 132cm Graphite (at night under the boat in the lights) and the only reason I hit the fish is because it was so damn big. Not because the gun was accurate eh eh.

 

[Mark Laboccetta]

Would you like to sell it? I have a friend wanting one...

Sell it to him...There is a reason yours is accurate and his isn't and it has to do with production. If you do the same test I mentioned to him I bet yours doesn't flex as much.

 

[Hugo63]

Hi Mark, so what you say is :some guns will be ok and some won’t ? I chose that gun for its look (best looking one I had ) but also because it looked very well built and designed, super light and very stiff. How carbon can be that soft ? I will do the test to load it and watch if there is a gap, but shouldn’t it be changed under guarantee then ?

 

[Hugo63]

So I did the test, and you were right the shaft is lifted by about 2mm and only rest in the rail for its first 1/3. Is that because the muzzle side of the barrel bend down?

 

[popgun pete]

When the C4 guns are molded a pressurised bladder inside squeezes the uncured gun frame outwards against the outer mold surface, but the bladder does not absolutely control where everything goes before the resin thermosets, so I expect that there may be some thickness variation in some parts of the gun even though the embedded carbon fiber sheets limit too much variation. On another forum a guy chopped the front end off his C4 Monoscocca and we could see that inside was not entirely uniform. Could be this is what varies between guns that outwardly seems like peas in a pod.

Here is a Graphite 132 shooting at 7 meters,

 

[Kodama]

When the C4 guns are molded a pressurised bladder inside squeezes the uncured gun frame outwards against the outer mold surface, but the bladder does not absolutely control where everything goes before the resin thermosets, so I expect that there may be some thickness variation in some parts of the gun even though the embedded carbon fiber sheets limit too much variation. On another forum a guy chopped the front end off his C4 Monoscocca and we could see that inside was not entirely uniform. Could be this is what varies between guns that outwardly seems like peas in a pod.
View attachment 55946

That is an interesting picture! Also quite worrisome since the wall thickness is thin on the sides and thick on the bottom and top. Exactly the opposite of what you want regarding stiffness.
I was under the impression these guns where solid in the handle and at the front.

The monoscocca is an older model though you would think they have figured it out by now.

 

[Mark Laboccetta]

Hi Mark, so what you say is :some guns will be ok and some won’t ? I chose that gun for its look (best looking one I had ) but also because it looked very well built and designed, super light and very stiff. How carbon can be that soft ? I will do the test to load it and watch if there is a gap, but shouldn’t it be changed under guarantee then ?

They are indeed beautiful guns. The problem is that as Pete eluded to, vacuum bagging carbon fiber spearguns is not a perfecct process like it now for C4. If you overbuild it accounting for these variables like they did with the Urukay then it is stiffer than most anything for it's weight. The Graphite in the longer sizes was an after thought of the more common Euro sizes 80-100's class guns Europeans are used to. By comparison my 132 is massive in comparison to the 116. See related images. This image is 6 years old. Those guns came out in 2010 or 2011. The new way they are producing the C4 Gladius is entirely different and more precise.

 

[Kodama]

How is it different? From another tread I understood these guns are made in a mould with a interior pressure bladder.
Did they chance this production method? Where did you get this information from?

 

[Mark Laboccetta]

Look this whole thing is interesting, I mean this thread. I haven't participated on deeper blue in a very long time but this thread somehow made itself into my Inbox. I'm having major Deja Vu here seeing Bill McIntyre and all these old friendly names on here, 10 year DB relapse...

I'm just happy to be able to contribute and help Hugo63 dispel some of his frustrations. I have literally been in the same boat. I bombed some world class fish with that 116 gun and I felt like you need to know its not you and it is the gun. Cannot go into what M.Bonfanti did exactly when he produced your gun but he made each gun himself and it WAS by far NOT a perfect science. The guns didn't have tracks because it was too much of a pain in the ass to produce.

If you look and compare any carbon fiber speargun designs, meaning all in one, monoblock/monoscocca, designs regardless of the brands you will see one diver loves his while the next with the same exact model hates theirs. This thread is testament to that. The only way to fix that mistake was to massively overbuild them and make them heavy examples: Bleutec and C4 Urukay. That is because again, that was an imperfect process as much as it could be as closed to streamlined in a production style setting at the time. We're talking about ten years ago and he was coming off the success of the Monoscocca model.

This gun was never clear to me because if I was going to buy a carbon fiber speargun for my personal use it was for one reason only: because I wanted a light gun, lighter than wood or aluminum and stiffer, Euro rear handle, light on the wrist and easy to point and train on the target and shoot.
And that is why, in my opinion, his fins are so popular and the guns were not. He got it right on the Monoscocca, the Mr Dark and the Urukay as a BW gun. As I said that was 10 years ago, things have changed. The Graphite is only made in 2 sizes now, the ones that work. The new gun from C4 is a light gun and a stiff gun, the entire point of using carbon fiber for a gun. Well suited for one or two strong bands and a thin shaft, not for up to 3 and a thick shaft like the Graphites were purportedly sold.

 

[popgun pete]

The problem may be occurring where the fat and wide body section transits to the much thinner long nose end of the gun as thickness variations there in the walls could create a flex point. Flex as in a bow limb, not a hinge. I used to work in the tyre industry and there flexible rubber bladders squeeze the “green” (unvulcanised rubber) tyre outwards in all directions onto the surrounding mold shell using steam pressure that both shapes and cooks the tyre. However a tyre is like a doughnut, it is the same in all radial directions, but a cucumber shaped speargun is a different matter and the inner bladder may only be an approximation of the desired internal shape, and each bladder, which stays in the gun, may not expand uniformly every time and you would then get wall thickness variations.

 

[Kodama]

Of what I understand today C4 is not just Bonfanti anymore.
The Gladius supposedly is designed by Marco Ciceri.

 

[Bill McIntyre]

I'm going to reveal my age here. Carbon fiber is pretty but wood works. It isn't going to bow because the walls are too thin, and you can drill holes in it. I have drilled holes in every gun I've owned. I had one Wong with three different sets of inserts for different reels. I've drilled holes in both of my Abellan and in my Ulusub. And since when did light weight become an advantage in a speargun. Here's an example of why I drill holes.

 

[Andrew the fish]

c4 has no track. End of story. The problem is right there. Shaft on itself, is unstable, because it is being pushed from rear end. No flex, or shaft harmonics can explain the consistent inaccuracy on a truckLESS gun, which is also combined with shooting high. Shooting consistently high is a sign of shaft flying above the barrel, because this is how trigger mech and bands are aligned on that particular gun. Further to this, thickness and stiffness of a barrel is governed by layers of fiber, not a pool of epoxy. I doubt a bladder can dislodge layers at all. Try this - bend your inaccurate carbon fiber gun over the knee and see how much you can flex it. Keep in mind, that bands, no matter how many, will not generate the same amount of flex, because thier applied force is aligned with the barrel. If it flex like a noodle, than yes, yours is a lemon.

Now something else bothers me. Your gun does not shoot well, and an advice is - sell it. Wow. Pass me hot potato. If the gun is beautiful, as you all agree, why not to tinker and fix what is not right. Add a track, or cut the groove, or sink the trigger. Hell, you can add a few layers of carbon fiber for less than 50$ and some elbow grease.

 

[popgun pete]

For the money paid you don't expect to make big changes to a C4. Guns without a track can shoot OK, such as the old Sampson gun which had no track at all and a big gap between the shaft and the barrel. The gun had an in-line pull muzzle and cranked back grip handle.

 

[Bill McIntyre]

I hated that Sampson handle.

 

[Hugo63]

They are indeed beautiful guns. The problem is that as Pete eluded to, vacuum bagging carbon fiber spearguns is not a perfecct process like it now for C4. If you overbuild it accounting for these variables like they did with the Urukay then it is stiffer than most anything for it's weight. The Graphite in the longer sizes was an after thought of the more common Euro sizes 80-100's class guns Europeans are used to. By comparison my 132 is massive in comparison to the 116. See related images. This image is 6 years old. Those guns came out in 2010 or 2011. The new way they are producing the C4 Gladius is entirely different and more precise.
View attachment 55949


View attachment 55948

Huge fish !!
So

Have you tried contacting C4 about this? Might be worth asking. Perhaps even include a link to this thread? Perhaps something to do with muzzle balance, as somebody mentioned above?

Over the years, I noticed several forum members get a C4 speargun but they don't seem to stick with them. Which surprises me as I would expect them to be the ultimate in versatility. Perhaps fear of loss/damage - or perhaps difficult/different to shoot accurately?

Would be good to have someone from C4, for sure !!

 

[popgun pete]

So I did the test, and you were right the shaft is lifted by about 2mm and only rest in the rail for its first 1/3. Is that because the muzzle side of the barrel bend down?

If the shaft is lifted off the track in the front 2/3rds then the muzzle must be pulling up as the block with the short track section at the muzzle must be raised. That will create the gap that you see. With the band tension off the shaft should sit on the track. You could try slackening the band tension by lengthening your wishbones or moving to a forward wishbone slot to see at what point you don't see a gap, in fact just try loading up with one band. 2 mm is not much, although of course you would rather have no deflection of the muzzle. If the gun tilts early in shaft travel it can lift the shaft up and send it high because the spear flies over the elevated tip, which is different to the muzzle clipping the shaft tail.

 

[Mark Laboccetta]

The problem may be occurring where the fat and wide body section transits to the much thinner long nose end of the gun as thickness variations there in the walls could create a flex point. Flex as in a bow limb, not a hinge. I used to work in the tyre industry and there flexible rubber bladders squeeze the “green” (unvulcanised rubber) tyre outwards in all directions onto the surrounding mold shell using steam pressure that both shapes and cooks the tyre. However a tyre is like a doughnut, it is the same in all radial directions, but a cucumber shaped speargun is a different matter and the inner bladder may only be an approximation of the desired internal shape, and each bladder, which stays in the gun, may not expand uniformly every time and you would then get wall thickness variations.

it’s simple. There is just flex in the front of the body after the bulge. That’s it.

 

[Kodama]

it’s simple. There is just flex in the front of the body after the bulge. That’s it.

Yep and it shouldn’t be there. And there is no easy way of fixing that unless you are going to rebuild it.