I wouldn't worry about trying the 100gr load with a round ball. The max of 100gr 2F is based on a 400gr bullet. Your RB is less than half that weight and will not produce pressures as high as the 400gr bullet will. The only time you would get into trouble would be if you short start the projectile. Try it out you may find it likes it. The Bobcat is a solid little rifle for the price.

It sounds like your Bobcat is a shooter. I like the 3 I have.

Good luck with it.