The Otis field (cable) cleaning kits come with short brushes. This is one of my favorite cleaning kits when I want to do a better job. Even though I own several carbon fiber and teflon coated rods I almost never use them any longer.
I love the .17HM2 and own (3) at the moment, an Anschutz 1702, CZ 452 Varmint and Volquartsen Standard. I'd love to add one of these uppers to my .17HM2 collection, even more than a dedicated .22lr upper. http://ballisticadvantagellc.com/17M2.php
I use the Walther PS55 sight on my Colt/Umarex. Like the Leapers it uses the battery compartment as a riser to clear the front sight post and it works well. It's the sight Colt uses in their ad campaign photos.
I guess those restrictive Ct gun laws are failing to keep guns out of the hands of the gang bangers. Probably doing a real fine job of neutering the law abiding folk though, huh.