Aspects of gun design.

[scallywag]

Just thought I'd throw the question out there to the more experienced gun builders on the site. Now that I've dipped my toe into the realm of speargun construction and gone about the design in a somewhat "organic" manor, I'd now like to understand more fully what makes a good speargun apart from looking nice. I've been thinking about a skeletal carbon design to minimise drag in the horizontal tracking plane but am concerned about the lack of mass having an adverse effect on recoil. Is there an ideal weight for a gun of a given length or is it all about shape and balance?
Any thoughts or input welcome.
Thanks.

 

[Tin Man]

Every design is a compromise. I might give up mass, in exchange for greater maneuverability and sharper recoil, to hunt in murky water. Or I might want a heavier gun, to provide stability for taking longer shots in clear water, but accept that I can't swing it as quickly if a fish appears suddenly. Similar trade offs for shaft diameter, overhang, handle placement, balance, band size / quantity, and on and on.

To me, it all starts with an honest evaluation of what you want to do with it, and what parameters are most important to you.

But then, that's the fun and addiction of building guns. Pretty soon you've got an arsenal to choose from. Thus insuring that you will always grumble to yourself, "I should have brought the other gun . . ."

 

[foxfish]

Absolutely agree the more guns the better
When you build a big bulky gun, but one that is perfectly balanced underwater, its like firing a recoilless sniper gun & is perfect for sniper style fishing.
However when you build a tiny slim profile lightweight, high power gun with a short spear it kicks like a mule but tracks like a shotgun.
Only one choice build loads..
I have been (still am) very busy with house renovation & boat building so I haven't built any guns for the last 6 months.
I did start a new project using a 120 airgun, making a mid handle & a carbon cover for it but the gun still sits in my shed waiting for me....

 

[scallywag]

Thanks for your answers. my current train of thought is to make a minimal mass skeletal carbon gun around a foam core structure and add mass back in to counter buoyancy and counter recoil (active anti recoil device?). I probably won't start it untill the autumn but it doesn't stop me from day dreaming!

 

[foxfish]

Great idea, think about a 28mm carbon barrel gun like the ones readily available - they mostly sink with the spear in place and are muzzle heavy!"
So to go any more minimal is not going to work!
The most important aspect of any gun is the balance in the water, if the gun sinks like a stone or is not balanced then I consider the gun a failure.
I like to have my guns just hovering in the water if you let go of it, the gun should just hold position in a horizontal plane.
Food for thought.....

 

[scallywag]

I was thinking perhaps of a mechanism so when the spear was released some sort of counter balance moved rearwards to negate the recoil, think Newtons third law. I know of a top end spring powered air rifle which has a similar system. Lightweight speargun with little or no recoil? hmmmm.