This may seem overly simple, or vague; If so help me ask the correct question.

It would seem that suppressor makers do not follow OSHA, or NIOSH methods of TWA testing for a NRR; as is done with hearing protectors.

Why not?
Don't you think it would help, being a more consistent way of giving "good" information as to a how much reduction could be offered?

I understand that different operating systems of guns can play havoc with the numbers, but wouldn't it be more helpful if the numbers followed already established methods??

Thank you for any help offered.

Good question Darkker. Reads like a fight within our government though. BATF would have something to say as well. I'll think on that some for now.

Cheezywan

Not sure what point you are trying to make but the TWA doesn't have anything to do with the NRR. You will use the TWA to determine what hearing protection or exposure length is called for but the TWA is not part of the NRR calculation.

What I think you are trying to get at is not really related to the TWA but really just a consistent testing methodology for the NRR. It won't meet the testing criteria but an easy way for shooters to check it would be with a cheap sound level meter and just check the peak dB level. Just fire a shot with and without the suppressor. The dB level with the suppressor will tell you all you need to know. In this application I think that is more important than trying to calculate the NRR. The suppressor would really be considered an engineering control anyway versus personal protective equipment so I am not even sure the NRR formula would even work.

__________________
"But when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security." U. S. Declaration of Independence, July 4, 1776

Darkker I agree OSHA has an easy established system that a good number of us follow every weekday. The different sound thing has no value a pneumatic jackhammer and a grinder is different frequency and they measure that. I was surprised to learn that they did not follow this system but this is just what's going on in my haed

I guess what I am after...
The NRR of ear plugs or muffs, isn't a total reduced Db. It is a value over time and a range of audible human frequency. Thus the TWA(time weighted average) reference. Suppressor makers don't offer clear NRR numbers as do the hearing protection folks do.
It would seem if they follow the rating system of hearing protection, that it would(could?) be a more relevant rating system for folks interested in "how effective" the suppressor is at reducing noise.