Sarg-

Funny -- the *only* squib round I've ever popped was *the first round* through my Whitworth .458

My mate at the ranch had a container of loaded ammunition he wanted to give me (350gr, evidently medium loads) and I know him to be an ultra skilled handloader.
Turns out (via the little card at the bottom of the case) his nephew loaded the ammo and didn't neck-size the brass properly.
We immediately pulled all the bullets and dumped the powder.
I then detailed all the brass and loaded it back properly.

Gotta say, at the bench the sound of a hiss-pop definitely pinched my heartbeat for a moment. Secondary ignition would/could have been quite a bitch with a plugged bore!

A bolt gun action full of powder is no quick self-cleaning proposition either!

Cheers
Tinker