Sims makes a silencing kit for crossbows. I believe it consists of a set of Ultra Limbsavers, two sets of string leeches and some form of cable slide dampener. This should help considerably. The reason I say this is because I also purchased a Barnett...the RC 150....to use after Christmas during our muzzleloader season. It isn't as loud as the Revolution or Rhino Sport Mag to begin with but I did slap on two sets of limbsavers...a set of Ultras on the inside of the limbs in the typical spot...and a set of mini-limsavers on the outside of the limbs right next to the stirrup. Both sets together definitely made a difference on the noise level.

Hope this helps.