What is Necksplitting?
Necksplitting is the outcome of over-stretched or resizing of the cartridge. Necksplitting is most common when the cartridge is excessively resized. Necksplittting can be seen as a crack in the cartridge.
Why Do Case Necks Crack on Polymer Cased Ammunition?
True Velocity ammunition is made with carefully engineered polymers. Damage to the polymer may occur during firing if the polymer is required to stretch farther than intended before it receives support from the chamber walls.
How to Solve the Recurring Necksplitting of Polymer Cased Ammunition
Consult a qualified gunsmith to inspect the chamber of your firearm. The gunsmith should ensure that the chamber of your firearm is in compliance with the Sporting Arms and Ammunition Manufacturers’ Institute’s (SAAMI) specifications for the specific caliber or round. Keep in mind that most protocols for checking chambers include an assessment of chamber diameter. Just like brass, if the chamber is too large in diameter, splitting can occur in the cartridge.
What is the Sporting Arms and Ammunition Manufacturers’ Institute?
The Sporting Arms and Ammunition Manufacturers’ Institute, also referred to as, SAAMI, is an accredited association of American manufacturers of firearms, ammunition, and components.
Why Do Case Necks Crack on Brass Ammunition?

The Breaking Point of Brass Cases
Since brass is a mix of copper and zinc. Any type of gas can affect its brittleness. Methane, chlorine, and even gas coming from a pound of decomposing gunpowder can affect the material. Another possibility of why neck splitting is occurring could even be caused by improper annealing from the factory. All brass is annealed and is usually polished afterward.
How to Solve the Recurring Necksplitting of Brass Cased Ammunition
It is recommended to always anneal your brass. It is a good idea to keep the brass separate from primers and powders until it’s loaded. In addition, there could possibly be volumes printed on what could be causing the neck splitting.
Contact Virtus Ammo Today
Our team at Virtus Ammo aims to test our polymer cased ammunition as in-depth as possible to prevent the possibility of neck splitting or other issues. Our manufacturing process is precise and highly accurate. We are continuing to test and compare the polymer cased ammunition to other manufacturers’ products.
If you have more questions about neck splitting in the cartridge, contact the Virtus Ammo polymer experts today. Our team of ammo experts can assist you in narrowing down your issue and solving it.