Bullet Bob:
1)Thanks!
2)I just contacted Smith & Wesson and following is the information that they gave me, regarding cleaning the aluminum alloy cylinder(etc.):
a)There is no coating on the Model 617's with the aluminum alloy cylinder-as it is just has a polished finish. So, no worries about any finish peeling off!
b)Do not use an Lead-Away cloth to clean the cylinder-nor, anything else that is abrasive(Mild or otherwise?)!
c)Do not use bronze bristle brushes to clean the cylinder holes(Nor, stainless steel brushes!)as these will scratch the aluminum! For brushes, use only nylon bristle brushes!
d)Birchwood-Casey "Sheath" is good to use to clean the cylinder bores with because it doesn't leave a wet, oily film-but, it drys completely-and, although this is a dry lubricant, this won't cause the .22 caliber cases to back up in the cylinder to bind up the gun during shooting(Like a wet lubricant will do!)!
e)There were no durability or timing problems with these 617's with the aluminum cylinder-because the ejector star is the same steel one, that is used with the stainless(10-shot cylinder)! Also, since the aluminum cylinder has less inertia during rapid firing than does the stainless steel cylinder, there isn't any more of a problem with peening of the cylinder bolt stop notches, than would be with the stainless steel cylinder!
f)That these model 617's with the aluminum cylinder were only discontinued because of poor sales-but, not because of any durability problems!