Looking good although the barrel looks a little thick or maybe short. That might be the camera angle.
There were two 75mm versions using the round turret. The earlier one had a shorter barrel and a simple, single baffle, muzzle brake. The later version, also seen on the FL-10 turreted vehicle was longer (it was essentially a French manufactured version of the gun from the Panther tank with a new muzzle brake the most obvious change). I think your gun might need a little lengthening.