That is a clever setup. Be careful though relying on the clamp to hold the tube locked in place as you can easily crush it out of round. Most folks use some sort of stop that the breech block or receiver end can butt up to to provide a way to keep the reciever from sliding forward when a lot of pressure is applied to the main spring assembly like with a magnum springer. That way you can just snug the center clamp without having to use a lot of pressure to lock the tube in place.
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