My buddy just called me and he says this fell out of the barrel of his AR that he decided to clean today.
How does this happen? How can this be left in the barrel and he nor I noticed it since we were shooting together at the range last week.

Anybody have any ideas how this happens??

Only thing I can think of is that the rounds didn't have any neck tension (or were jammed into the lands) and right before he packed up he ejected a live round and the bullet stayed. He's probably got a lot of powder and debris hanging out in the barrel extension.

If he's reloading tell him to check that his setup has enough neck tension after sizing. If he's using someone else's (see: Bubba's pissin hot reloads from the gun show) reloads, slap him upside the head and tell him to stop that.

This and tell him to put a crimp on it if he is reloading them.

Could have also been the last round fired was a squib round and yall just got lucky and didn’t shoot the gun again. But if it was a squib it wouldn’t just fall out which leads me to believe it’s what Hickshunter said.

This is wilson combat ammo so no it is not cheap stuff. I have had nothing but excellent ammo from them back when I shot it from my 6.8spc. But anything can happen with any manufacturing process.

This is also a complete 100% Wilson Combat AR that he purchased from them. So typically the machining is very good plus he has at least 300 rounds through it so far without a hiccup.

I have never seen this happen before myself. I still dont understand what happened. ammo or gun?

He is my hunting buddy and we have several night hunts coming up this winter so we need to get this figured out beforehand. He just put the new Pulasr thermion LRF XP50 Pro on it and it is such a nice set up. I do take credit for making him by the Wilson.

He should get a few loaded cartridges and mark the exposed bullets with a sharpie all over. Chamber them and eject them without firing. If the OAL is too long and the bullet is pressing into the rifling it will show now. I would do that first.

Ok testing it is definitely a good idea. Thank you

Hold the case in the hand and tap the nose on tabletop. If the bullet moves, not enough crimp. I do suspect it jammed the lands though.

Looks like 300 Ham'r 125gr Sierra Prohunter bullet. I wonder if he left a completed round in his suppressed rifle. The case/bullets turns green and gets almost stuck in the chamber slash barrel. Looks like there is a ring around the bullet where it touching the rifling. Might have semi welded itself and when he ejected the cartridge it powder went everywhere and left the bullet in the barrel.

I left a chambered round in my suppressed 6.8 and this exact thing happened. Only difference was I couldn't open the bolt; after doing the buttstock-slam it opened and fortunately the cartridge stayed intact. It was green and nasty and tried to weld itself in.

He said when he tore it down there was no casing in the chamber. Just the bullet and gun powder everywhere. So I am guessing it must have been a bad crimp. Luckily he cleaned it before his next trip.

Thanks guys!