Speargun too heavy at muzzle

[Villette]

Hi guys,

Recently, I made a home-made invert roller speargun.I try to strike the perfect balance, but the gun is a bit muzzle-heavy. In salt water, the speargun is slightly positively buoyant with the shaft in(Vertical with muzzle down). How should I adjust my speargun? Should I add more wood to the muzzle?

Thanks in advance for your feedback.

 

[Bill McIntyre]

Hi guys,

Recently, I made a home-made invert roller speargun.I try to strike the perfect balance, but the gun is a bit muzzle-heavy. In salt water, the speargun is slightly positively buoyant with the shaft in(Vertical with muzzle down). How should I adjust my speargun? Should I add more wood to the muzzle?

Thanks in advance for your feedback.

I'm afraid I've never built a speargun so I'm not the best one to answer your question, but since none of the people who have built one have replied I'll take a crack at it. Do you want the gun to be positive with the shaft in? I wasn't until the last few of my 70+ years of spearfishing that I I got guns that were positive, and then I wondered why all guns for free divers were not built that way. It's so nice to throw the gun off the boat and have it wait for me, or turn loose and adjust my mask with both hands while the gun sits there beside me. In my case the guns were Abellans and Ulusubs that has compartments for adjustable ballast fore and aft, so I was just a matter of removing lead from these compartments. If the gun was muzzle heavy I removed more lead from the front compartment. But that probably isn't an option for you. I wouldn't know how to add wood to the muzzle but I would think that would be difficult after the gun was finished. So assuming you want the gun to remain positive, how big a deal is it that the gun floats vertical? I had a couple of guns from which I couldn't remove enough front ballast to get then to float horizontally, and it turned out not to be a big deal for me. If I placed the gun horizontally in the water and it took several seconds before it ended up vertical, then I wasn't even noticeable when I dove with the gun. It's not as if it was hard to hold the tip up to aim a a fish. It was just a matter of ounces difference between the buoyancy of the front and rear of the gun and It didn't matter whether the gun floated muzzle low or muzzle high. I couldn't feel it.

I hope a speargun builder will come along and help soon.

 

[Villette]

I'm afraid I've never built a speargun so I'm not the best one to answer your question, but since none of the people who have built one have replied I'll take a crack at it. Do you want the gun to be positive with the shaft in? I wasn't until the last few of my 70+ years of spearfishing that I I got guns that were positive, and then I wondered why all guns for free divers were not built that way. It's so nice to throw the gun off the boat and have it wait for me, or turn loose and adjust my mask with both hands while the gun sits there beside me. In my case the guns were Abellans and Ulusubs that has compartments for adjustable ballast fore and aft, so I was just a matter of removing lead from these compartments. If the gun was muzzle heavy I removed more lead from the front compartment. But that probably isn't an option for you. I wouldn't know how to add wood to the muzzle but I would think that would be difficult after the gun was finished. So assuming you want the gun to remain positive, how big a deal is it that the gun floats vertical? I had a couple of guns from which I couldn't remove enough front ballast to get then to float horizontally, and it turned out not to be a big deal for me. If I placed the gun horizontally in the water and it took several seconds before it ended up vertical, then I wasn't even noticeable when I dove with the gun. It's not as if it was hard to hold the tip up to aim a a fish. It was just a matter of ounces difference between the buoyancy of the front and rear of the gun and It didn't matter whether the gun floated muzzle low or muzzle high. I couldn't feel it.

I hope a speargun builder will come along and help soon.

Thank you for your valuable advice. I want the speargun to float horizontally and slightly negatively buoyant with the shaft in. (I think this is the perfect balance for a speargun.) Currently, I am considering redesigning the muzzle to make it wider or thicker.

 

[xXxorcist]

I have been building timber guns for nearing 2 decades. I never make my guns positively buoyant with the shaft in. I always make them slightly muzzle heavy. The reasoning is if the gun is loaded and the gun released, it will never point at you. This does mean that float lines and floats are my preference and the reasons are numerous. With timber guns, it is easy to machine / router rebates in the stock and laminate lighter timber to get the balance right if you did not calculate the area of the stock, density of the timber and the weight of all of the hardware first. Here is one example:

 

[Bill McIntyre]

I have been building timber guns for nearing 2 decadses. I never make my guns positively buoyant with the shaft in. I always make them slightly muzzle heavy. The reasoning is if the gun is loaded and the gun released, it will never point at you. This does mean that float lines and floats are my preference and the reasons are numerous. With timber guns, it is easy to machine / router rebates in the stock and laminate lighter timber to get the balance right if you did not calculate the area of the stock, density of the timber and the weight of all of the hardware first. Here is one example:

I suppose that its possible that a gun that is positive will point at you if released, although its highly unlikely if the gun is muzzle heavy. Will you release it and then swim under it? A guy on my boat last year saw me attach my gun to a tuna clip and throw it over the side so It wasn't in my hands going off the swim step. Of course it was not loaded. He did the same but unfortunately he didn't know how to attach clip and the gun went to the bottom at 55 feet where the vis was about 2 feet. In Southern California the most dangerous thing we do is to cut white sea bass out of the kelp on the bottom. Even though we may not practice strict buddy diving on my boat we spot each other. I'll go over and hold the float line or reel line while may buddy goes down to cut the fish out. If my gun is negative what do I do with it? I'm using both hands to pull on my buddy's float line or reel line. I can wrap my float line around my arm and let my gun dangle but then a loaded gun is pointing down. So I need to unload my gun and then reload it later. That's a PIA. But with a positive gun I just park it in the kelp next to me. I belong to a SoCal FB group. Very frequently someone will post that he lost his gun coming through the surf, or maybe marked a lobster hole with it and couldn't find it again, or myriad other ways. Guys shoot big bluefin tuna offshore in thousands of feet of water. Of course they are using breakaway float line and big floats but things can get pretty busy chasing the float and it's easy to let go of that gun. Most of these guys are relative beginners but they learn hard lessons losing expensive guns. I used to suggest that they might consider using guns that were positive but I quit doing that.

 

[xXxorcist]

Typically, my guns are attached to a float line and float. For boat diving, I rig it and dump the gun over the side and keep the line looped around the boat cleat until I role in. When I am using a breakaway, I will use my belt reel to keep the now unloaded gun on me. (though I hate these things). Again, always slightly muzzle heavy when loaded to have the gun pointing down. If there is a chance my gun may point at someone, it is always unloaded. My dive buddies welfare is far more important than a little time to load a few bands. Kelp and coral diving do present some unique challenges but a horizontally floating loaded speargun is not a scenario I wish to partake in.

 

[Mr. X]

All my aluminum and carbon tube guns have all been muzzle heavy. I tried sticking a cork in through the hole in the muzzle of one ( probably my old RA Sparid 90cm barrel), it helped but did not fix the problem (as I saw it).

I gather now that this is a common issue for smaller tube guns as they have much less bouancy than longer barrel versions, because the bouancy is mainly from the hollow tube barrel.

Even more of a problem with big, heavy modern roller muzzles. I see Coatesman on YouTube fits his small model with lighter bearings for that reason. Shorter spears and/or less spear overhang can also help reduce muzzle heaviness.

I think the modern reverse-trigger mechanism on my 95cm Apnea rollergun pulls the spear back 5cm, reducing the spear overhang accordingly. It also has a ( vinyl?) cuttle-fish shaped barrel cover which presumably adds buoancy near the trigger mech.

Dano of Mako spearguns offers a "cuttle- fish"-shaped barrel add-on to help with the balance and/or buoancy of his very nice rail guns when switching to a roller muzzle. (See his excellent YouTube videos ).

So perhaps some buoyant wooden cuttle-fish shaped wings on the side of the barrel might help you. Near the muzzle might reduce recoil but inhibit movement. Near the other end of the barrel might increase overall buoancy but not lighten the muzzle so much. If this interests you, it would probably worth checking out other wooden spearguns which use side wings (I've seen images of several, usually big blue water guns).