Slot shape and band alignment

  • Over a year ago I had an idea about shaping the band slot of a wood gun in such a way that it would allow control of how the bands run when the gun is loaded. The idea was hatched the due to the perceived necessity to elevate the bands as close as possible to the level of the spear, so as to reduce muzzle kick. Back then I still thought it was an issue with a wood gun with two bands. The idea was that the band fills the conventional hole when not stretched but when stretched it is forced into the smaller hole thereby raising it.





    Many builders opt for cutting channels/contours into the stock to control band alignment. I've never owned nor loaded such a gun, but I did make up my mind about two things. 1. These contours make the gun stock more bulky. 2. Sometimes for the bands to make use of the contours care must be taken when loading them so that they occupy their respective places, this takes more time and loading effort. I've always maintained the shape that best combines minimum necessary mass and hydrodynamic movement is a straight stick that is taller than it is wide. The addition of the stretched bands on such a gun makes the gun body round. Whereas on a Riffe Euro where the stock is wider than it is tall in the first place, the stretched bands compound the width making it IMO very inconvenient to hold.


    Anyhow I forgot about all this because muzzle kick was no longer an issue. But since I started using a new gun, and I like to load both bands on one tab, a new issue came up. The bands were running/stacking over each other when loaded instead of running in a compact manner from the band slot to the tab. This is very important to me as it makes carrying the gun when loaded inconvenient, I carry it by the stock. If the bands stack one on top of the other it increases dramatically the profile of the gun body and it's hard to close your hand around it. Since this gun already has a bigger all around stock than what I normally prefer to use, the stacking bands increased the inconvenience to the point that I almost concluded I will not be using the gun. So in an effort to salvage it and make the gun more streamlined I remembered this old idea and came back to it.


    This is what it looks like.




    My original thought was to leave each band in its hole so I shaped one hole angling up and one angling down. I though it through carefully before cutting but I f**ked it up, I did it it the opposite way, due to the nature of which band gets loaded first, and the bands stacked even worse than before :dumb: I thought I messed up the gun for good. Then I decided to try one more thing, put both bands in the first hole.


    It worked beautifully, just as planned except well :) I used it all day yesterday. The first band that is loaded occupies the small space. The second band runs right under it without any special loading effort. When both bands are loaded the gun is as tight and compact as can be, I'm very satisfied. And in the end there's room for a third band which I wanted anyways as an option, since the stock on this gun has enough mass to support it. It remains to be seen how this third band will run. But the main point is that for two band guns this type of slot is the shit IMHO! Getting two bands through that little hole required putting one band through the hole and loading it thereby creating space for the second band, and then lubing the second band with dish detergent. However there is no reason not to make the slot extend a little more towards the muzzle, it will not change the alignment effect.








  • I thought there was when I first inserted the 2nd band without dish detergent :) and the safety factor of having to load one band to insert the other. But then like I said you can make the slot a little longer.

  • Very interesting! Little changes can make a big difference! By the way, if you are taking a vote, this avatar INMHO is WAAAAY better than the other one!

  • my thinking is thus...the band is a linear force generator, it pulls equally in both direction until it is at rest. we anchor one side of the bands on our gun and the other to the spear tab so that the linear force goes into the spear and rives it away from the gun...by orienting a band across the flat plane of the spear you are compromising the physics of the band to not just pull the spear in one direction, but now towards the muzzle and down into the stock...this is fine and good for the spear, but the force on the other end of the band now has to go somehwere...since the spear is shot out of the gun and the gun is braced against the shooters hand, the gun will not recoil stright back, rather the force of the band pushes up on the muzzle. this is increased the more the bands are angled as opposed to straight parallel to the spear....ill try to draw something on paint to illustrate it.


    in my opinion there is no denying the fact that the bands to raise the muzzle, i just am not convinced that it does it enough to be a factor

    i like to spear fish

  • in this high tech scematic i have drawn, the blue lines are the bands and the red lines are meant to indicate the forces on the speargun at tension.


    the pink circled area shows, as best i can, the two forces on the muzzle, one pulling the spear through and a second, much weaker on lifting the muzzle

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