[Thorgrim]

When shopping look to the measurement of decibel reduction. The higher that number the "quieter" the muff.

Absolutely. Remember that decibel isn't a linear scale, it's exponential, so a muff that gives even a 2-3 greater dB reduction than another muff is likely to sound twice as quiet in comparison.

 

[Thorgrim]

If you want some really good earmuffs I can't say enough about a pair of Peltor 10's or H10A's

Both are cheap (~$20), comfortable and very effective.

I have a pair of the H10A Peltors that I use mowing, weedeating, and running a chainsaw. I haven't shot in them, but they are great. I forget just how good they are until I lift them to scratch my ear and break the seal.

 

[Thorgrim]

This is good info, I didnt know that.

Actually, I oversimplified it, but the description I used gives a "seat of the pants" idea.

There's an entry on Wikipedia here:
http://en.wikipedia.org/wiki/Decibel#Acoustics_2
that gives you the detailed calculations, with earmuffs the acoustic measurement is used. We used the "A" weighted measure (dBA) in mining to test all work locations for excessive, damaging noise. I no longer remember how to do the math, but I was just reading the meter when I did the testing anyway.