Thread: Primer question

Originally Posted by zimmer

Not so much more sensative but a thinner cup. Typically 17 thou versus SR primers at 20 - 25 thou.
I use SP primers in my Hornets and get better results than with SR which have a stronger spark.
There is a risk of puncturing a primer though.

You are right, hence the '' around the more sensitive bit. By way of explanation for anyone not aware of how this works, the thinner cup means less force is required to get the necessary amount of crush of the priming compound between the primer's cup and anvil to successfully initiate priming compound burn when the firing pin is released. It also makes pistol primers easier to initiate during handling, or easier to ignite through improper priming techniques. When primers are shipped the anvil is not pressed home inside the primer cup, this is a way of desensitising the primers during shipping. When we prime cases, we squish the anvil back into the primer cup and against the priming compound layer inside the cup and this sensitises the primer ready for initiation by the firing pin. It's also why pistol primers are easier to ignite accidentally over other grades of primer and why pistol primers are considered easier to pierce when used in rifles but are also considered to have more reliable ignition characteristics.