So I know these are two very popular cartridges, but I wonder if the 40 has surpassed the 9mm in gun and ammo sales in the past 5 years in America? Without a doubt the 9mm is more popular world wide, but America seems to have taken favor to 40 based on gunships chatter, and discussion in friend circles. What do you think? posted using Outdoor Hub Campfire Wanna kill these ads? We can help!