I shoot a YHM Phantom on my 308 and it is hearing safe, haven't wore ear pro since I bought it unless I'm around other shooters that are not suppressed. The subs out of the 308 are stupid quiet and if I shot from a bolt gun would be even quieter, but I shoot from a LR308. Had a guy send me a message after this last hunters rifle challenge and ask about my suppressor, he said it sounded quieter than the others that were shooting suppressed. Love my YHM Phantom.
I also have a can that was made on a form 1 so I guess you can call it a custom suppressor. I run it on my 22LR upper and my 223 upper. The can is only 5 inches so if it had more volume it would be quieter, but I wanted something as short as possible to put on my SBR. 223 is still hearing safe sounds like a HV 22LR round, and takes away the concussion felt when shooting the 223 SBR. I've never tried sub sonic 223 rounds, I don't really see the point in them. The 22LR is very quiet when shooting with the can on.