James,

To measure the barrel, close the bolt and drop a cleaning rod down the muzzle until it rests against the bolt face.  Then, just mark the cleaning rod at the muzzle and measure it.  Most cutdowns are 22 inches, although some are 24 inches, and I have heard of a couple cut to 20 inches too.  My sporter is 24 inches!

As for cleaning, I would remove the bolt, and just run some patches down the bore!

Paul