kiwifruit

Thank you all for your very helpful responses! I am quite relieved that I haven't bungled things up as it were.

Just a bit of background. This is my first firearm purchase, and I really just know the bare essentials (if even that). I'm slightly concerned I have screwed up the tail portion of my M4 bolt assembly. Heck, I don't even know what this piece is called. History: I shot about 7 buckshot rounds initially, then 30 Winchester birdshot rounds. After shooting the M4 I cleaned out the entire gun with Otis 085 Solvent. Just about 6 months later I took the gun out without further lubricating it (idiotic, I now know). I shot about 50 Winchester birdshot rounds, had a few failures so I poured in some Otis 085 Solvent into the chamber. There were repeated failures during the day, in total about 250 Winchester birdshot rounds were shot. From reading the forums here I think I did three things wrong 1. shot about 20 rounds from the hip 2. did not lubricate well prior to shooting 3. did not use a better lubricant. I get home, open up the gun, and the pics below show what the part (the name of which I do not know) attached to the bolt assembly now looks like. My question is whether I've really just screwed the part up here, or whether this is normal wear and tear. Thank you and best wishes

Ignore please, duplicate post.