Pat,  Have you ever figured out why the beautitians and fingernail artists have a rep for being "ditsey"?  occupational disease, just like the "mad hatters" back in the previous centuries when mercury was used to process the fur into fel and shape it into hats.

aside from that.  I mostly use a rod every couple relays to push the crud out of the bore.  however the new ruger has a real tight match chamber---I have to use a breech seater.  and the lube build up in the chamber mouth needs cleaning every so often so I'm starting to pay more attention to bore and chamber care.  There is a whole lot of anecdotal material and theories about bore cleaning and conditioning out "there".  However in the 22rf world we have a whole different set of conditions that centerfire and centerfire BP.  This is one of the reasons I started this thread.  To see what kind of data/experience/belief/convictions we have here in the ASSRA/rimfire community.  I suspect that the BR50 guys and the NRA smallbore competition shooters may have a bunch of info/experience we can tap into and apply to our end of the game.

Re the use of sub calibre rods:  As I understand it a properly fitted rod will be just a precise slip fit in the bore. anything less can allow the rod to flex and bang against the interior.  I suspect that it is the action of pumping the rod back and forth that has the most potential for damage.
In theory the first tight patch through should push out anything not cooked onto or embedded in the bore.  
 I've never, in recent years, used a brush.  I simply push patches through until they come out clean.
However I'm researching and reconsidering my practices. 

The best bore quides have an insert placed on the rod which is then inserted in the actual quide itself, it's tight, properly fitted you cannot push a brush, for instance, through the insert. 
 Since you mentioned the chamber, here is another little update-curveball for you. You'd be surprised at how a lot of match chambers are being cut these days. Some of the best of the best match chambers no longer engrave much if any of the drive band . A good friend that has made barrels for a substantial number of IR 50/50 hall of famers cuts a chamber with no engraving at all. I am currently shooting a one-off chamber reamer that only engraves about 1/4 of the drive band. Lots of this stuff is designed to deal with the fouling in the throat. 
 Also just an FYI,BR50 is today essentially dead. Today the largest organizations in decending order are probably IR 50/50, ARA and RBA. Go over to the home page of BR central, all the org's have their links there, you can see the targets,records, etc. it's all pretty neat... horrribly frustrating. I'm up in Syracuse, N.Y. and we shoot IR50 about 3 out of 4 weeks a year from April thru October. If I can help anybody with the care and feeding of quality .22's I'd be happy. Also, I don't want to sound preachy here but again this .22 BR stuff has taught us a lot about .22's particularly in the last couple years, once you can get past digesting $10-$12 a box match ammo, the rest is easy.