What’s a wildcat cartridge? In simple terms, it’s a way of creating a new cartridge or caliber, by tweaking some aspect of an existing caliber. An easy example are Ackley Improved calibers. The idea is by making a steeper shoulder angle, you can have more straight body in the case, and more capacity. So an Ackley Improved 243 Winchester can be formed by firing a 243 Winchester case in a barrel with the Ackley Improved chamber. As pressure in the case rises, and the brass heats up, it will expand to fill empty space. You may have heard of ‘blowing the shoulder out’ which is what you would be doing. Wildcats can be created by tweaking many aspects of the case. Some are worth the trouble, some aren’t, and we’re going to discuss some of the advantages and pitfalls!