A high strength polymer-based cartridge casing can include a first end having a mouth and a neck extending away from the mouth. Next, a shoulder extends below the neck and away from the first end. The cartridge can have a frangible portion capable of being split upon discharge of a projectile. A projectile can be disposed in the mouth and a relief can be disposed on the neck near the mouth and projectile. The relief can form a gap between the neck and the projectile to receive an adhesive.