I have an Ruger Mark 3 upper. It has been threaded for suppressor (concentric to bore) It was also used for a few years for my bullseye league at the club. The barrel is 4.75" long and the guy who threaded it didn't cut off enough of the barrel and the hole drilled for the front sight can be seen in the treads. (see pics) its a cosmetic thing only and has never been an issue shooting suppressed. This upper has a few handling marks and blemishes in the finish, it doesnt look bad, but just wanted to be up-front.
The LCI (loaded chamber indicator) has been ground flush to keep the brass from jamming up on it. This is a good shooting barrel/upper and would make a great addition to someone who wants to keep there nice MKII original and put this on to go out plinking. Comes with the matching thread protector.
I have a power custom scope mount that could go with it for $20.00
$125.00 + shipping (This needs to go to an FFL)