You'll find a bolt to be extremely quiet with a suppressor and regular sub-sonics. I really don't know that you are gaining much by using the quiets with a suppressor.In answer to Throttle....not semi auto because:
1. Already have like 4 Ruger 10/22's and a M&P 15-22
2. Trying to get the quietest .22LR rifle possible and semi-auto's won't cycle the bolt on the CCI quiets.
MOst lever guns has a magazine tube under the barrell which will make is dificult to threat the barrell and attach a suppressor. I'm not saying it can't be done but I am saying it would be a lot more work to shorten teh Magazine and thread the barrell than to just threat the barrell on a bolt gun.