Polymer cartridge with enhanced snapfit metal insert and thickness ratios

A high strength polymer-based cartridge, comprising:

• a polymer case, comprising:
• a first end having a mouth;
• a body formed below the mouth and having a propellant chamber and a longitudinal axis;
• a back end, opposite the first end, and formed below the body, comprising:
• a first snap ridge comprising a first ridge angle;
• a first snap spacer having a first snap length depending from the first snap ridge and away from the mouth;
• a first snap slope depending from the first snap spacer and away from the mouth;
• a second snap ridge, positioned closer to the first end than the first snap ridge;
• a second snap spacer having a second snap length depending from the second snap ridge and away from the mouth;
• and
• a second snap slope depending from the second snap spacer and away from the mouth;
• wherein the second snap length is shorter than the first snap length;
• and
• an insert configured to engage the back end.