Off the top of my head, it's a 22 inch barrel and a 8.25 twist.
I have to take off the fore end with all the barrels. I don't see it as a big deal as it adds about 2 minutes to the barrel changing process.
I think they did that to make sure the barrel stays put, rather than as an oversight. I know there are people here with a lot more knowledge about the PSR program who could tell us why that is.