Light Primer Strike on Mossberg Shotgun, Photo
This actually happened with Mossberg shotgun which had the firing spring broken, but I have taken a photo to show you how light primer strike looks like:
If you see such marks on extracted shells which failed to fire, you need to check and replace hammer spring to fix this problem.
Read also: Infographic: Remington 870 vs Mossberg 500
Vitaly, the first rule for such shells in not to touch them after ejection, slow detonation possible…
Stan, thanks for this advice, I have forgotten to write about that. I have taken those shell after some time, not immediately after extraction.