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To balance your speargun, insert the shaft and attach the tip to your gun. Distribute ballast weight across gun until it balances (in water while resting on your finger) just in front of the handle. Machine recesses into gun in the places determined by the weight distribution step. Insert the appropriate amount of weight into these recesses.

Note balancing does not mean the gun will be neutrally buyoant. See ballasting details for more information.

Here is a message from Kitto concerning distributing the mass to maximize the second moment of intertia to achieve more stability.

"I had posted to the list a question about how to distribute the mass of a gun to achieve the ideal balance about two weeks ago. To summarize the previous post - the gun should be neutral with the shaft and tip in it. This basically means no matter where you are in the water column - if you let go of the gun - it stays right there where you released it. The point raised in my earlier note was that the gun can do this in more than one way. You can, at one extreme, have all the mass concentrated near the handle with the center of gravity slightly in front of the handle. The other extreme would be to have the center of gravity still slightly in front of the handle but with a large mass near the rear of the gun and a smaller but balancing mass at the front of the gun. I had proposed that the centralized mass would allow the gun to swing about rapidly - but the distributed mass would be more stable. Several people sent me private email almost unanimously indorsing that the rapid swinging capability of the centralized mass idea was preferable. I think I later mentioned that I had just made a gun with the centralized design. What I would like to report now is that I changed that configuration last week to the distributed mass concept and took it out last Sunday. The early report is that the distributed method is much better than the centralized one. Let me further describe how you go about doing this and an added side benefit to the approach I took. The gun was an enclosed track Delrin model with a fairly beefy stock (67" long built on 1.5" by 2.3" Teak with a wider margin in the rear) sort of like a extra thick and extra long Alexander Magnum. To this I added Mahogany rear side stocks about 26" long and went through a lengthy iteration process at my neighbors swimming pool of machining pockets and casting lead in the side stocks to achieve a neutrally balanced gun with the center of gravity just slightly in front of the handle. The rationale behind using Mahogany is that it is more bouyant than Teak and this way you have far greater control of where you put the center of mass by the addition of lead when you balance the package. The gun was well balanced but too easy to move for my taste. What I did to distribute the mass was make small triangular shaped side stocks that I counterbalanced with lead until they were neutral (used a bucket of water instead of neighbors pool). I attached these with thru-bolts (same way I did the rear side stocks) but just behind the band slot and right even with the bevel that goes up to the track. This has accomplished two things - the gun now has a large second moment of the mass about the center-of-gravity and it is extremely stable when held on target (it is still easy to move around - just not as easy as it was). The second and now I think important aditional effect was the bands now go up over the front side stocks and pull exactly parallel with the shaft. This means that all the forces go inline with the shaft and there is no downward force that you get in normal band guns. The field report is that it doesn't flinch when shot one handed and the 72" shaft is at the end of the 25' shooting line right on target in light speed. I think all things considered I now far prefer this configuration to the previous one." Bill Kitto