Has anyone had luck contacting S&W for a new barrel? I'm considering getting one, 18" lightweight. Mine was having cycling issues with 7.62x51 when it was new, so I opened the gas port from. 068" to .073" (at least that's what the gunsmith claims) but now it appears to be overgassed. I'm getting a ton of cycling and ejection issues. I have tried an XH buffer and spring, new extractor spring, adjustable gas block, and it's still jamming with live rounds and spent brass in the chamber. Very annoying.
So I'm considering trying again with a new barrel.