I'm trying to get the handguard off of my Colt M4 to look at the barrel. I found light rust on my other AR barrel and want to make sure I don't have any on this one. You're supposed to pull the Delta Ring away from the forearm stock which should release the two halves of the handguard. Is this just a brute force operation? I can move it almost far enough to see the end of the handguard, but not quite. There's a stout spring behind it.