What is the quietest suppressor for 6.5 Creedmore

What is the highest decibel reduction suppressor for 6.5 Creedmoor? I am thinking about getting one but am completely confused which one has the best performance.

I’m not hung up on it being an actual 6.5mm suppressor, .30 is fine, I’m just looking for the most objectively effective.

You worried about length? What’s the use of the rifle?
 
I'd recommend seeing what comes out at SHOT.
Lots of suppressor manufacturers will be releasing new cans in January to coincide with the market opening back up once the $0 tax stamp goes into effect.
 
Now you are moving the goal post. I would pick the suppressor for your application. "Quietest" suppressor would actually be lower on my list of what I would want in a suppressor. Most of them are going to be decently quiet. It's hard to tell a lot of suppressors apart, and there is a lot of tonal differences in them as well. Meter numbers are not the end all be all when picking a suppressor.