How Primers Are Made — Video from Federal Factory
Do you know how gun primers are made — how the explosive elements are applied into those tiny cups? Find out by watching this video filmed at a Federal ammunition factory. It starts out with empty primer cups loaded, 1000 at a time, into trays using vibration (0:05 time-mark). While much of the process is automated, there is still a significant role played by production workers who apply a green, paste-like charging compound to the inside of hundreds of primer cups.
At the 0:17-second time-mark you can see the factory worker “charging” the primers with the priming compound. After the cups are filled, then the plate of cups “mates up with a plate of anvils” (0:40 time-mark). Then the primers are unloaded from trays and inspected.
Primer “Mysteries and Misconceptions” Article
There is an excellent article about primers on the Shooting Times website. This authoritative Shooting Times article explains the fine points of primer design and construction. The author reveals some little-known facts about primers and corrects common misconceptions. Here are some highlights:
Video find by Boyd Allen. We welcome reader submissions.
Size Matters
Useful Trivia — even though Small Rifle and Small Pistol primer pockets share the same depth specification, Large Rifle and Large Pistol primers do not. The standard pocket for a Large Pistol primer is somewhat shallower than its Large Rifle counterpart, specifically, 0.008 to 0.009 inch less.Magnum Primers
There are two ways to make a Magnum primer — either use more of the standard chemical mix to provide a longer-burning flame or change the mix to one with more aggressive burn characteristics. Prior to 1989, CCI used the first option in Magnum Rifle primers. After that, we switched to a mix optimized for spherical propellants that produced a 24% increase in flame temperature and a 16% boost in gas volume.Foiled Again
Most component primers have a little disk of paper between the anvil and the priming mix. It is called “foil paper” not because it’s made of foil but because it replaces the true metal foil used to seal early percussion caps. The reason this little disk exists is strictly a manufacturing convenience. Wet primer pellets are smaller than the inside diameter of the cup when inserted and must be compacted to achieve their proper diameter and height. Without the foil paper, the wet mix would stick to the compaction pins and jam up the assembly process.
