Always visual check ammo before you load it into your magazines.
What I found when I was rotating my Home defense ammo

I always look the ammo over before I load up my magazines I don't know how I missed this but luckily I found it to day when I was rotating my mags.
Out of curiosity I checked to see if it would chamber in the rifle yes it did..
The neck of the case is still there it has been rolled over and crimped.
What kind of problems could this have caused me??