Well, I'm putting my first build together and I got a little ahead of myself. While inserting the barrel back into the trunion I accidentally damaged a few threads so I wont be able to get a slant brake on there, slightly mushroomed it actually. Anyone have a fix for this, I think I canprobably file them down some but want to do it the right way. Any suggestions for this noob mistake?

Thanks- nhg21

You can try the proper thread file if the mushrooming is slight (very). Otherwise a professional repair is called for. Is there any damage to the crown and/or the rifling? Next time you need to drive a part like this, try to protect the barrel by either threading something onto the barrel that can take striking or use a mallet that is softer than the barrel(or both). Is this type of installation typical on an AK? That is, is there a better tool for this job than banging on the front of the barrel? Be careful and good luck on your build.
Josh

Its slight and I think I can repair it. The top three threads are the issue, I used a piece of wood to try and protect it but this is obviously the wrong choice.  Just did a search on thread file and I think I might need the thread cutter, nope I need a file - I'll have to hit the local hardware shop and see if they got it.

you just need to chase the threads with a die