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Case Priming

Primers are small metal-clad cups that hold priming mixture, an anvil, and a foiling disc. Primers fit into the case’s primer pocket, creating a spark when hit with the firing pin.

Case Priming DiagramConsistent powder ignition is mandatory for ammunition to perform efficiently. You need precise tools that seat primers consistently and under flush.

The case must be primed before adding new powder, so that your gun’s propellant powder can be contained at the bottom of the case.

First, check to make certain you have the right size. Primers for U.S. cartridges come in two diameters — large (0.210”) and small (0.175”) — and two general types — rifle and pistol. Rifle primers have more rigid cups and a hotter flash than pistol primers.

  1. Case Priming DiagramClean the Primer Pocket – Check for any powder and primer residue that may have contaminated the primer pocket, and use the Primer Pocket Cleaner to remove it.
  2. Chamfer any Military Crimp from the Primer Pocket – Never prime military cases without first removing the crimped area that held military primers in place with the Primer Pocket Chamfering Tool.
  3. Primer Seating – To push primers into the primer pocket of your cartridge case, use the Co-Ax® Press, our multipurpose handloading machine, or the Co-Ax® Primer Seater, a tool dedicated exclusively for priming. Insert each primer, open side up, into the priming tool’s cup. (Before handling primers, always wash your hands to remove any oils or lubricant. Powder-free latex medical gloves can help you safely handle primers with greater dexterity.)
  4. Separate any cases with primer pockets that are too loose to hold a primer securely. This situation can occasionally occur if the previous load fired with that cartridge case was too “hot.”

Warning - Always store primers in their original, compartmentalized packaging. Handle them with care and respect. Primers that touch each other are more dangerous than single primers.

As you become more proficient in reloading, you will fine-tune your own process based on your tools/equipment, the type of shooting you do, the guns you reload for and the goals you have for your handloaded ammunition. We suggest that you continue to read, learn and understand various methods so that you can find the system that works best for your needs.

Safety - Please follow all pertinent safety procedures such as wearing safety glasses and hearing protection, being in a well-lit and well-ventilated workspace, and having all reloading tools in top working condition and no flames, sparks or static electricity.

Suggested Further Reading