Gnoahhh,
As you already noted a long barrel helps to keep the noise down significantly.
I shoot CCI Standard Velocity out of a CZ with a 24.+ inch barrel and it is hearing safe and very accurate. About $450/case right now (that's shipped).
https://www.targetsportsusa.com/cci...40-grain-lead-round-nose-0032-p-895.aspxTen shots CCI SV @ 50 yards out of a Tikka T1X, the black square is one inch;
I had two cases of CCI Quiets. I dedicated a Remington 580 single shot with a 4X scope for the round. No where as accurate as CCI SV, but quieter. I used it on eggs at 50 yards and surprisingly even with the poor trigger on my 580 I could almost do as well as I could with CCI SV in my CZ (Shooting offhand). I could never get these to run in a Ruger 10-22 until I took Volquartsen's 22 short Kit and tweaked it for the Quiets (Also tweaked this kit to run 22LR Birdshot). The "Semi-Auto" 45 grain Quiets which CCI came out with later ran in my 10-22 just fine though.
https://www.targetsportsusa.com/cci...40-grain-lead-round-nose-960-p-3345.aspxI tried CCI segmented Quiets in my 580 and was disappointed only because they did not hit to the same point of aim as the regular 'Quiets'. However, it was much better for vermin.
https://www.targetsportsusa.com/cci...-segmented-hollow-point-970-p-58637.aspxI tried CCI CB Shorts (in a LR chambered rifle) & Longs, Aguila Colibri, Aguila Super(?) Colibri and Aguila 60 grain SSS. None were accurate enough for a head shot beyond about 12 to 15 yards. Colibri's come with a warning about sticking in rifle barrels, however, I never had a problem.
For those with 22 Short chambered rifles, the CCI CB Shorts and Target Shorts are both extremely Quiet. The CB's were as accurate as the Target Shorts in my rifle, however the target shorts are approx. 100 fps faster.
Browning SA-22 in 22 Short;
Jerry