Returned 3 of them.
I'd go to MDW, numrich and HKWebshop to request notification for when they receive replacement 762 barrels. They seem to come into numrich and mdw more than hkwebshop.
Once you land one, send it to someone and have it chopped. You can look for a Burk MR308 AGB for it as well. Then you'll have the closest clone to real as you can get without blowing $0000's on a real used assaulter barrel.