Thanks all.  Quite an education on delrin rods.  My Ruger is a 32-40.  Guess I will talk to a local smith about getting one turned for jags and brushes.  I'm not happy with the "from the muzzle" approach.

What case that one can drill out would make a handy muzzle guide for the .321 bore?  A .22 Dewey rod sorta works from the breech but is a pain and not something I want to do alot of.

Yes, Dewey does still make a brass .30 muzzle guide..complete with rubber O-Ring for muzzle protection.  I use one on my .32-20 Colt Bisley..Brownells/Sinclair sells them.

Some years back there was a lot of discussion over on the big benchrest site in the 22rf section about barrel cleaning and rods.   The 22rf BR guys are over-the-top fanatics ---at least out to 50 yards or so .  (I kind of gave up on them when I found little that applied to 100 and 200 yard accuracy) 

But, they change barrels constantly, the min. they think there might be a bit of wear.  So bore wear caused by cleaning is a real hot topic.  
They were pretty uniformly down on the coated rods,, brass rods or plastic rods; Any material might possibly pick up any primer grit, embed it in the surface like a lap, and cause premature wear.  Their solution is a surface hardened one-piece spring steel rod precision-ground to bore dimensions so it can't flex or pick up primer grit.
  There are a couple guys in their "specialty support group" who custom make rods for them.  I did buy a long rod that works in "our" rifles and a shorter non-rotating one for chamber and throat cleaning.

I have "in stock"  1/4" delrin rods with brass ferrule tapped for std 8/32 female for jags and brushes. 
$18 postpaid. I use it to good effect in 32-40 on down to 28 cal 
pm me
beltfed/arnie

If bore wear is a concern all you have to do is wipe the Delrin with a rag between passes. My Douglas barrels used with mild loads 1/25 alloy no antimony and good lubricant never need more than a few patches to come clean.   Take a lifetime to harm a quality barrel with a rod at that rate.

Boats