The SFX is a redesign of PMC's Starfire bullet, which utilizes ribs and flutes in order to strategically weaken so it may double its diameter during penetration. This bullet's hard jacket not only ensures that it can penetrate a target reliably, but furthermore facilitates smooth feeding in a semi-automatic. The bullet's profile itself works toward that end as well, so you'll be far less likely to be put over a barrel by a jam when you've chambered an SFX round. The round's brass casing, non-corrosive primer and case mouth that are both sealed against intrusive water, and uniformly loaded propellant are all similarly able to be counted on during a fight, making this round totally worthy of your weapon for self-defense.