Hi John. Thanks for choosing LuckyGunner.com. RN stand for the design of the projectile. This bullet is a "round nose" design which is an inexpensive bullet, designed primarily for range, and training. Other designations you might encounter might be "SP" or soft point, (an expanding round) or "HP" or hollow point (used for self defense). Give me a shout and we can help you pick the right bullet for your shooting needs. Ross