Not really defending JES but, during any machining process, things can go wrong. Likely that during the rifling process, something didn't go as planned. Maybe a cutter broke and scored the bore. In which case the barrel is now useless. At least by boring to 358 you have a functional barrel that you can either use or sell for another barrel.
Does seem like a detailed explanation and a heads up would have been a nice courtesy however.
I've seen other smiths who would've just handed you the screwed up 338 and acted incredulous when you discovered the issue. So kudos to JES for fixing and refunding. If you've ever tried to call, you know it can take multiple messages and a few days of phone tag to finally connect. So I'm not totally surprised he just went ahead and did it. (Though I would've appreciated a voicemail.)
For everyone saying Jason should have just rebarreled, this is really an anomalous result based on usual reports of JES guns and at $250 it's still way more economical than ordering a barrel, waiting for it, then paying a smith to install it *correctly.*
