I have always used ear plugs rated for chainsaw work while shooting. They carry 32 or 33 decibel protection I believe. They seem adequate outdoors, even when shooting 460 magnums (though it's probably unsafe in hind site). But I have started going to indoor ranges more lately, and when I'm shooting a 3" 357, the noise level is unpleasant. When my after holiday funds are replenished, I plan to buy some electronic muffs and double up. No reason not to.
I was out shooting an FNP-45 once in the woods when I thought I heard a dirt bike coming. So I pulled one plug out and listened, to make absolutely sure there was no safety concern. I wasn't shooting across a road, because doing so is both illegal and stupid, but I wanted to be safe. Well, the dirt bike moved out of the area, and I raised my gun and fired.
The ringing in my left ear only lasted a few minutes, but it was enough of a reminder to never be absent minded about hearing protection again. I simply forgot to put the plug back in. And that was only with a 45 acp. I immediately thought about how bad it could have been with a magnum round.
It made me totally rethink using 125gr 357 rounds in my HD gun, as I realized that the blast would be horrendous indoors without hearing protection, as is likely going to be the case if caught off guard. Standard 38 specials and 45 acp at the most. No more in home magnums.
It's also a reason to consider a threaded barrel and suppressor.
Protect your ears, and no more experimentation!