I have two sugestions for you.
1. Buy some CCI CB caps and try them in the LONGEST RIFLE you have. Sound level will be very low. Accuracy will be great. Power is OK for squirrel out to 35-40 yards (bullet stops under skin on far side), so head shots up close are a snap. Price is about 5.00/100.
2. Buy a 22 caliber air rifle that can get 800 fps. It will perform way better than the 117 @ 1100 fps. 117 tends to pass thru leaving very little damage. I've never dropped a squirrel with a body shot. Body shots with a 22 puts them on the ground. 200.00 will buy a 800fps 22.
http://www.compasseco.com/
http://www.airgunexpress.com/
Compasseco sells cheaper stuff. REMEMBER: A new spring piston air gun must be broken it to be accurate. 1000 rounds or more. Scopes for airguns MUST BE AIRGUN RATED. They will eat almost any standard scope, now matter how expensive.
I've shot air guns for years, trust me. The lower priced Chinese 22 can be pretty accurate and under 200.00.
http://www.compasseco.com/index.php?...=1&prevstart=0