Band Risers

Here are a few examples of band elevators I have used on some builds with conventional band slots.

MN

Well I'll say this. Those are a LOT more aesthetically pleasing and they do not detract from the look of the gun. I would rather see builders make the band elevator also be a stabilizer wing. If you are going to do it, kill two birds w one stone.

With an open track gun, wouldn't some down force on the shaft be desirable? To keep it being guided by the track?
Band elevators make perfect sense in description, but I have never tied one. if the band slot is as high to the shaft as possible.... isn't that good enough? I have been positioning the top of the band slot at a 1/4" below the bottom of the track and the results with 3 bands on a 55"-57" gun are very accurate.
Perhaps I need a bigger gun with more rubber to see the problem.

Arrows shot from bows have no track....just the correct spline cycle for the wt. of the bow. The arrow bends around the bow before going into true flight.

Cheers, Don

If you really want to split hairs about gun accuracy....band elevation does become a vital issue.
Accuracy is relative...I have the chance to test guns in pool at least once a week, 12 months/yr for 2-3 hrs for the past 3 years or so.
IMO designing a speargun should start at the muzzle..that is if you are too concerned about accuracy.
By accuracy I mean that you hit bullseye at the maximum effective range of the gun....so for a 100cm gun....I go for 4 meters and extend beyond to determine deviation & power of spear...any gun will be accurate at 1 to 2 meters....so no use for this.
During testing at the outer limits of gun...the muzzle...i.e., band alinement does come into play...and very much so.
The more the bands are in line with the shafts plane...the more the accuracy since muzzle flip becomes more of a horizontal direction during recoil...which remains in line with the direction of the pointed spear to target.

Take an enclosed track gun for example...this too has a long debate about ET being more accurate than OT........IMO.......ET are more accurate not for the enclosed track itself (unless you are overpowering the gun) but simply because for this type of track you find the spear embedded lower in stock than usual and the bands are higher...i.e.....the bands become more closer to the plane of the shaft.

When I first started designing spearguns...I couldn't dive more than 5 meters...everyone around me was doing 10 to 20 meters....so my emphasis was on taking long shots....long shots need accuracy...thus my concentration on muzzle design became a priority...and from there everything else follows....with the right stock, balance & ballast.....etc....you'll have an accurate shooting gun.

Ihab