I was at the range Monday night for our long range league night. I offered to spot for a 12 year old kid who was shooting his dad's AR-15. When the kid squeezed the trigger, I could hear the hammer release, but there was no mark on the primer from the firing pin. Each time we would need to beet the charging handle back to extract the round. He was shooting some reloaded ammo. I'm not sure of any specifics of the gun or the ammo. The father kept trying to blame the new mags on the issue, as last time there was no problem. It sounded like it was a fairly new gun though with only about 50 rounds through it. Everybody else that was present seemed to agree that it wasn't a mag issue but we weren't able to reach a consensus on what the problem likely was.
I thought that he may have loaded the rounds to long. When the round was chambered and the bolt closed the bullet was shoved into the lands of the barrel making it difficult to remove. Because the round was to long the bolt didn't fully close. When the trigger was squeezed the hammer was released but it didn't actuate the firing pin. Hence no primer strikes on the primer.
I'm not really sure of the mechanics of an AR15 so maybe one of you guys with experience could chime in and let me know if this seems plausible or if there is something else going on. Mostly I just want to make sure that if the guy comes back next week I don't have a gun blown up next to me, or worse, in a kids face.