TKOverKill

I am proud to announce that I did my first modification a few days ago!
I swapped out the barrel in my SOPMOD. Was nervous at first but got through it without to many issues...

HOWEVER
When I opened my SOPMOD there was some horrible gouging/scratching along the top and right hand side of the top receiver, just behind and above the hop up unit access window. Has anyone else seen this? What might cause it and are there any suggestions on what to do about it...

Thanks.
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Is it because the bolt cover moving?

Yeah... isn't the bolt moving exactly there ?

Put some lubricant dude

Normal. Mine had the same. I didn't do anything with mine. As long as it cycles fine, that's good enough.

thanks all. Q had the magic answer. Just wanted to make sure it was normal