Any idea what could be causing this?

[MilitantBEEMER]

So I built a left handed AR, and the Stag Lower was giving me problems.
First, when I would fire a shot it would not load the next round. I took the upper and put it on a different lower and it runs perfect.
I decided to dig into it and change out the mil spec trigger with a Larue. When mounting it in my gun vise, I noticed the buffer is all marred up. I have never seen that before. Any ideas? As always, thank you in advance.

 

[O4L]

The BCG is a little short letting the buffer come too far forward and hit the retainer.



Or there is a rough spot on the BCG beating up the buffer.

 

[GC7]

Yep SOTAR has many vids on this topic.

 

[MilitantBEEMER]

Yep SOTAR has many vids on this topic.

Who is SOTAR? Thank you

 

[Harp13]

 

[MilitantBEEMER]

View attachment 420468

I guess if I had paid attention to the video above, I would have known that. Thank you

 

[mr ed]

Only seen black airsoft buffers. Use the real deal.

 

[MilitantBEEMER]

Only seen black airsoft buffers. Use the real deal.

The buffer came in the buffer kit I ordered with the lower. I did however order an offset pin and a new H2 buffer from KAK this morning

 

[JEVapa]

Check and make sure you have a good carbine spring too and not a rifle spring. I think SOTAR has a discussion on this if I remember right as to how to tell the difference.

 

[MilitantBEEMER]

Check and make sure you have a good carbine spring too and not a rifle spring. I think SOTAR has a discussion on this if I remember right as to how to tell the difference.

Thank you. I have some extra new carbine springs and will switch that out as well.
This issue explains why It would not go all the way into battery.
Thank you OKSHOOTERS for the help and advice