The Sniper Carcano M91 is, as is, is not as strong as it should be, because of 3 main reasons. The first, is that the normal M1891 Carcano rifle is already on BR1, and that the rate of fire is significantly lower than the normal version for some reason, only 46 RPM (with 55 for the normal version). The third reason is that the Sniper Carcano 7.35mm is on BR1 as well, and for a negligible difference in damage of only 0.7, it has a much faster rate of fire of 62 RPM and shares the same reload speed. Below is an image comparing the main stats of the 3 weapons, all values found in the Enlisted Resource.
Because of those reasons, I suggest buffing the rate of fire to 55 RPM to match the normal version’s speed, and to move it to BR1, since it will be very similar to the normal M1891 Carcano, as is similar with other guns and their sniper versions.