Nick,
I hope you have better luck than I did. I tried several times and gave up after being on hold for an eternity. When I finally did get a hold of someone, I apparently stumped them with the part I needed. She transfered me to "technical assistance" which turned out to be Remington. I got an answering machine where I left a message two weeks ago. I still haven't received a response.
By chance, does the forearm on your Sidekick have a spring-metal retainer that keeps the ram rod in place? That is the part I need. According to the person at H&R, the schematic doesn't show this piece.
Bill