Do you remember my home built 38 inch reef gun with the butter-knife trigger? Well I just couldn't help myself! I had to have a 48 inch gun to go with it.
After a summer of hunting with the 38 inch version I found a logical area for potential design improvement. I wanted to try to maximize the potential for shaft speed by removing the material along the gun-stock that the bands come in contact with as shaft and bands travel down the gun. I purchased a large chamfer bit with a guide bearing for my router and removed a good amount of material along both sides of the top of the 48 inch gun barrel. This should reduce the potential for friction between the bands and the gun barrel and help the 48 inch shaft get up to speed faster. Does it really end up making a difference? Well I'm not sure. When the gun is fired underwater I assume the bands are not really making contact with the barrel anyway because I imagine a thin film of water is compressed between the gun-barrel and the bands (hydroplaning) as the wishbone travels down the gun. Perhaps with less contact pressure between bands and gun barrel the "hydroplane effect" will come easier and the spear shaft will reach even higher speeds before it leaves the gun. I also considered "band risers" as a way to reduce friction between the bands and the barrel. I believe that the downward force on the back of the spear shaft that comes without the band risers keeps the back end of the spear shaft firmly in the barrels guide groove as the spear shaft travels down the barrel. In the case of this design I feel it probably adds to the guns accuracy.
Another thing I did with this new gun was a complete redesign of the pistol grip. I created a strong and comfortable grip from hardwood that's secured to the bottom of the gun barrel by a stainless steel base plate. Doing it this way allowed the grip to be mounted without "through bolting" which meant that there was no physical interruption of the surface that the bands ride on.
The trigger mechanism, safety, muzzle, and line system in my new gun is unchanged from the first gun. The performance and durability of those systems have been excellent.
I have a web page that offers more photos and a bit more information about building these guns. Here's a link to that page: http://flshoredives.nexuswebs.net/biggun.html
Through "Spearboard" I've met a diver/ spearfisherman that goes by the name "dagodiver". Dagodiver offered me some much appreciated assistance that allowed me to complete my new gun to the standard that I had envisioned. Dago is a very accomplished machinist who's also built his own speargun and accessories. Thank You Dago!
After a summer of hunting with the 38 inch version I found a logical area for potential design improvement. I wanted to try to maximize the potential for shaft speed by removing the material along the gun-stock that the bands come in contact with as shaft and bands travel down the gun. I purchased a large chamfer bit with a guide bearing for my router and removed a good amount of material along both sides of the top of the 48 inch gun barrel. This should reduce the potential for friction between the bands and the gun barrel and help the 48 inch shaft get up to speed faster. Does it really end up making a difference? Well I'm not sure. When the gun is fired underwater I assume the bands are not really making contact with the barrel anyway because I imagine a thin film of water is compressed between the gun-barrel and the bands (hydroplaning) as the wishbone travels down the gun. Perhaps with less contact pressure between bands and gun barrel the "hydroplane effect" will come easier and the spear shaft will reach even higher speeds before it leaves the gun. I also considered "band risers" as a way to reduce friction between the bands and the barrel. I believe that the downward force on the back of the spear shaft that comes without the band risers keeps the back end of the spear shaft firmly in the barrels guide groove as the spear shaft travels down the barrel. In the case of this design I feel it probably adds to the guns accuracy.
Another thing I did with this new gun was a complete redesign of the pistol grip. I created a strong and comfortable grip from hardwood that's secured to the bottom of the gun barrel by a stainless steel base plate. Doing it this way allowed the grip to be mounted without "through bolting" which meant that there was no physical interruption of the surface that the bands ride on.
The trigger mechanism, safety, muzzle, and line system in my new gun is unchanged from the first gun. The performance and durability of those systems have been excellent.
I have a web page that offers more photos and a bit more information about building these guns. Here's a link to that page: http://flshoredives.nexuswebs.net/biggun.html
Through "Spearboard" I've met a diver/ spearfisherman that goes by the name "dagodiver". Dagodiver offered me some much appreciated assistance that allowed me to complete my new gun to the standard that I had envisioned. Dago is a very accomplished machinist who's also built his own speargun and accessories. Thank You Dago!