Priming Kaboom — Primer Flash Sets Off Multiple Primers in Tray

Here is an important safety reminder for readers who employ hand priming tools with trays of multiple primers. In this instance a primer detonated while being seating in a pistol cartridge case. This caused a “flash-over” which instantly ignited multiple other primers in the tray. That, in turn, caused a small explosion which broke the tray and Hornady Handheld Priming Tool. The user, a Forum member, posted this report this morning in our Shooters’ Forum.

Report by Forum Member about Primer Flash-Over Incident
I had a small scare the other day while reloading. My experience might be a helpful reminder to people to keep safe and follow proper procedures and not be sloppy.

A primer popped (went off) when being seated and (while hot) flashed over into the tray causing other primers in the tray to detonate. That, in turn, broke my Hornady Handheld Priming Tool and injured my hand.

Here is my loading area after the incident. Note the damage to the hand priming tool. I’m not not sure where the rest of the pieces are.

Injuries to User — Multiple Cuts on Hand and Forearm
This photo shows the resulting cuts to hand. Fortunately they seem superficial. Note — I was wearing latex gloves so my hand had some protection.

The blast also blew my glasses off my face and they landed about six feet away. Be careful folks and wear your eye protection! EDITOR: Guys — This is yet more compelling evidence why handloaders should always wear eye protection!

More Details — Primers Were Federal LP, Case Primer Pockets Had Been Checked
The forum member noted: “Just in case people are interested, I didn’t notice anything different from usual. Cases were Privi Partizan (PPU) factory brass on their fourth firing. The primers were Federal Large Pistol. The cases had been ultrasonic cleaned and the primer pockets checked prior to priming. I had primed around 50 cases during this session before the accident.”

Here is a close-up of “flashed” primers — note the empty but dented cups and triangular “anvils”:

This incident happened using a Hornady Handheld Priming Tool, as shown below.

Two other Forum members reported feeding issues with this particular handheld priming tool and one other member, Kiwi Greg, suffered a multi-primer detonation causing injury: “I had the same thing happen a few years ago now with the same Hornady hand primer with 50-75 [Federal 215M primers] in the tray. Made a bit of a mess of both my hands, blew primers and tray all around my large workshop. Scared the [heck] out of my employee who was near me at the time. Some stitches, bandages and it was all good, [but with] some wicked scars… I think a primer had turned side-on when being put into Bertram .408 CT brass which had nice tight pockets and required more force than usual. I use RCBS [priming tools] now with a flat bar that slides across to prevent sympathetic detonations. I hadn’t heard of it before, but found out it wasn’t that uncommon after it happened.”