First, I doubt your gun is choked for long range work, but the surest way to know that would be by doing some patterning. Get your chambers measured by a professional if you can't find the dimensions. It is most likely in millimeters. 3" is approximately 76 millimeters, and 2-3/4" is approximately 70 millimeters. Rather than Hevi-Shot in that gun, you might want to try some Bismuth or some tungsten matrix. I have been exceptionally pleased with the tungsten matrix personally. Any high powered load is likely going to smart a little out of a very light gun, and I have no experience how Bernadellis hold up to long term pounding with heavy loads.