Something very strange

[floydster]

Loading on my LNL press, loading 9mm, 147 gr. plated bullets with the Hornady bullet feeder die and the bullet feeder tubes.
I prime off the press so I was just belling the case dropping 3.4 grs. bullseye watching the powder cop die carefully.
Around the 150th round I had a flash, blew the cap off the powder measure, no other visible burns or primer ignition, all else was ok.
No smell of powder or anything, checked all the cases on the shell plate, all where ok.
I have re-loading for 60 years, never anything like this.
Static electricity., other thoughts?
Thanks for a reply, I am stunned!
Floydster

 

[gamestalker]

Sounds like static to me.

GS

 

[Captaingyro]

Except for the flash, it sounds like the cap was blown off the powder measure pneumatically, i.e, by air pressure. If you have the same black plastic top that I do, it seals pretty tight. I'm wondering if there was a pretty steep drop in atmospheric pressure between the time you filled the hopper and the time it blew its top.

With no smoke, no "burns or primer ignition", air pressure is a plausible explanation.