[Magpie]

I'll try and explain the basic concept.

In a normal airgun the spear gets pushed into the gun forcing the piston back down the barrel, compressing the air in the gun. Ok. But, when you push the spear in a load of water gets into the space vacated by the piston because the spear shaft does not fill it totally.

So, when fired, the piston has to push both the spear and all this water out.

Now, a mamba has a small sliding collar on the spear and a new muzzle. When you put the spear in the gun, before loading, you push this collar into the muzzle which creates a water tight seal around the spear. Now when you push the spear in to compress the piston no water can get in and a vacuum is formed within the gun. So when fired the piston only has to push the spear resulting in greater velocity.

Make some sort of sense? I can do some pictures later on if would help.