I bought another barrel off of Gunbroker and upon receiving it on Monday, I see two holes in the barrel extension, directly across from each other. It is a Green Mountain barrel that I bought off a third party seller. Wen I called Green Mountain barrel today, I had to leave a message that they have not yet returned.

What the heck are the holes for? Is it safe to mount and fire?

Before anyone says "Take it to Bert", know that I have already consulted with the firearm magician extraordinaire (and I say that with all seriousness as he is great!) and he does not know either.

Click image for larger version.  Name: get-attachment (1).jpg  Views: 69  Size: 254.4 KB  ID: 33229

Any thoughts?