The truth?

[Okanogan]

There was a long thread on the forum a few months ago about using suppressors on magnum hunting rifles. If you care to look up and review the thread it has a lot more discussion.
Overall, I would say the opinions in the thread were mixed about the effectiveness on magnums. Suppressors are just a tool/ accessory and the success or failure in meeting a user's objectives depends a lot on expectations. If you don't like the results on a magnum hunting rifle, you can always switch the can to another platform where you feel the results are more effective.

 

[Philward]

I've worn foam plugs most of the time at work and tried muffs alone and with foam plugs. Seemed to me the mugs caused more echo inside them and it seemed louder with them on when wearing plugs too. Plus we were required to wear safety glasses and the muffs don't seal around them. Been next to steam joint failures with 70psi steam blowing out and you see your co-worker lips moving but can't hear anything, can't hear yourself either for that matter. That with both hearing protection in. I prefer the standard yellow EAR foam plugs for everything unless it's just intermittent cuts on tablesaw then I'll use muffs.

 

[bengineer]

I have some experience here.
In the ear plugs measure about 5dB reduction. Muffs measure closer to manufacturer rating in the ear canal. The biggest reason is bone transmission of sound.
I demo cans for the uninitiated to familiarize them with what to expect. I have sold cans since 2008 without a disappointed customer. These facts are related.

To the OP: consider your expectations in your disappointment. Where or how did you get the expectation? Salesman? Video? Want? If you start over in that process, you may find you are happier with your purchase.

Lastly, we have several sources of sound. The round going off is one, and it gives us muzzle blast and some guns give action noise. Then we have the bullet traveling. Subsonic flight is quieter than supersonic. We cannot affect the sound from flight other than launch speed, but we can mitigate it by being away from large, flat surfaces that reflect that sound back to us. Even bushes can reflect some sound from a supersonic bullet back to us. Avoid those and you cut down a lot of noise. Conversely, using sound absorbing surfaces helps us at the ear. Ever shot from a hay stack? Amazing sound reduction. Using fixed actions cuts ejection port noise and icky combustion gases into our faces/eyes. Being aware of these things and setting realistic expectations will go a long way toward end user happiness.