I would guess the shorter coal is to reduce the volume of the space the power charge occupies. They would be using a light charge of fast burning power as charge weight contributes significantly to recoil
I like where this is heading but I think there is still a lot of room for improvement, especially in the grip area. I humbly submit for critique a quick concept sketch I did which I feel addresses some of these areas
It is very easy to calcuate with an online volumetric calculator and the materials specific gravity. You didn’t need to cut the end off your barrel to find out.
I have one of these scopes . At 720 grams I find it okay regarding balance and weight. Overall I am fairly unimpressed by it. Eyebox is fairly tight, its optically unremarkable, lowlight performance is a little disappointing and the illumination knob on the eyepiece has come unglued and fallen...