Building a hybrid?

I need a "mid water" gun for hunting cobia, amberjack, and taking longer shots on wary snapper. I find myself intrigued by the idea of building a hybrid. I have never built or even shot a hybrid, and I know that some love them and some hate them. So I would like any input about things you like, or don't like about them. I have a few ideas that I think would generally be improvements, and I'll try to post a sketch later. Starting with:

I'll make the tube myself. Using the techniques that Chad and I have used on our larger carbon fiber guns, I can make a tube 1-3/8" in diameter, but with an open track molded in the top, and filled with the core material we use to add a little mass. The 1-3/8" tube and 5/16" shaft, with an integral open track, is the same height as a much smaller 1-1/8" tube with a shaft sitting in a cheap stuck on plastic track, but double the strength. So side to side tracking should be the same as a smaller tube, with vertical tracking just a little slower. Wall thickness will be a bullet-proof 1/8", including under the track.

An enclosed delrin track in the wood section, slightly raised to allow the use of hard wishbones if I want. Sloped sides on the stock to keep the bands from piling up on top and in the way of good sight picture.

Fully enclosed Delrin muzzle with holes for up to 3 bands of either 9/16" or 5/8" diameter.

A cut out in the bottom of the wood stock to raise the handle more inline with the shaft and band pull. Why don't all the hybrids do this?

Overall length would be 58" or so, and I have calculated the weight to be just over 8-lbs. Every so slightly nose heavy with a short shaft, but able to handle 12" of overhang without a problem. The key to this is the slightly larger tube with greater volume.

Any and all constructive criticisms or suggestions are welcome. It's only on paper now, so this is the time for changes!

Quote from hau

Tin Man---Sorry, i forgot how you dive. Will this be a freedive or scuba gun gun please?

Some of both, I hope.

As for not being real euros, nor real tree trunks, I think that is the idea. In theory, they combine the best of both. Gone wrong, you get the worst of both, I suspect.

And I'll freely admit that some of the attraction is just to see if I can do it, and do it well. But for those who have used them and dislike them, what specifically turned you off? Is it something that could be fixed with a better thought out design, or a few minor changes to better suit your diving style? Or is there some inherrent flaw that you cannot see as fixable?

Very sleek lines. I see that he raised the handle a little. But I'm envisionining something with a little more mass. I think that most hybrids look the same because they are limited to what they can do with the tube. I'm not sure that I'm ready to tackle an elliptical tube because it would be hard to fit into the wood, but the 1-3/8'" with a deep open track should help get the shaft and handle closer together, which can only help, I think?

Interesting how he ran the tube all the way through the gun.

Yes, but I believe that he also said that it left sharp edges that really chewed through dynema wishbones. He built a muzzle that was beautiful, but larger because it had to fit around the outside of the tube because of the dowel inside. My tube will be thicker walled, but hollow at the end, so I can create a more streamlined muzzle, no larger than the tube itself.

I'm going to do some figuring and see how the balance of my design would be affected if I ran the tube all the way to the back. There is really no reason for the rear of the track to be enclosed, and it would eliminate the tube/wood joint as a potential weak spot.

I think that he also said that the tube inside a tube design left sharp edges that destroyed dyneema wishbones. And although his muzzle was beautiful, it had to be large enough to fit on the outside of the tube because of the dowel within. My tube will be hollow at the end, so that the muzzle can be as small as the tube diameter. Nice touch with the little stainless piece between the end of the tube and the trigger mech, though.

I am rethinking the idea of running the tube all the way to the mech. I'll have to do some calculations to see how that affects the balance of the gun.

The only one I've ever used was Chad's, so my perspective may be skewed a wee bit. I only shot twice, but it went right where I told it to. I guess my thought is that if I can keep the cost of the stock and tube reasonable, then everything else can be pulled off and re-used on a new build if I don't like the way it turns out.

As I evolve, I will freedive whenever my skills and the conditions allow. Since my allowable take of snapper has been reduced from 4 to 0 through May, and gag grouper from 5 to 2, I'll be a lot more selective about the fish I shoot as well, and will spend more time hunting Cobia and AJs. The annual migration of cobia off the Northwest Florida coast usually produces a few fish of 90 lbs or better, so there is always that possibilty on the nearshore wrecks.

I'm starting to flesh out some of the details, and understanding why nobody uses a 1-3/8" barrel, at least as far as I know. Ball end router bits are easy to find in 1-1/4" diameter, and 1-1/2" diameter, but no 1-3/8". So if I am hell bent on using 1-3/8", then I have to drill from the end, and cannot run the tube all the way through the stock like the pictures that Pucho posted.