When you say not very effective, what do you mean?

Do you mean that the sound aggro for zombies is the same as if you were shooting without a silencer?

Please clarify and expand your bug report.

Can expand on this, Sound is still the same sound as is when firing without a silencer and yes zombies are still aggro'd as if no silencer was in place. Confirmed myself last night with a Prestine silencer just to be sure!

There is no SD ammo yet

Sound not modified. still aggro zombies and players :)
But with silent ammo it might works, you're right.

This is a duplicate report. Please use the search function before posting an issue.

Refer to 0001104: Suppressor loudness for further development or to provide additional information on the issue.

Thank you.

Duplicate of #0001104

Please consider closing duplicate reports and commenting/voting up the original in order to make it easier for the devs.

Also, before reporting, please use the search function to check if the issue has already been reported.

We all profit from that. :-)

Regards,
Johnny