when I started reloading I produced a 9mm squib and a 45 acp squib for a revolver.

The 9mm was stuck highly but unable to chamber another.

And as someone said: The revolver squib was deep in the barrel.

Since then I installed a tactical flashlight on my Dillon frame and I look into each brass before seating a bullet on it. I made it a habit to look as I turn the plate to the seating stage. Never any sqibs since then.