A posted stated that a 357 is twice as loud as a 357. Allow me to put some simplified math here so as many as possible can understand this.
Every 3dB gain is 2X as much, every 10dB gain is 10X as much.
The difference between 140 and 143 dB is 2X as much.
The difference between 140 and 150 dB is 10X as much.
100dB is a jackhammer.
130dB is the Pain Threshhold
140dB- 150 dB is standing 10 feet from a jet engine.
170 dB is having someone crack off a 30-06 with the muzzle 1 meter from your ear directly to the side.
A measurement of a particular caliber from a standard weapon 1 meter from the muzzle in either the wide open or an acoustics chamber only gives you the base value. A near by thunderclap rates 120dB and that alone can cause permanent damage. That is 1% of a gunshots Sound Pressure Level (SPL). Remember 10dB is 10X as much and 20dB is 100X.
Resonance can change these numbers. Being close to a wall can add 3-6 dB (2-4X) depending on the surface, distance and angle. A corner can add 9 dB (8X). A narrow hallway can really jack the numbers up. Crack a short barrel 22 off in a hallway and you WILL be over 140dB. That is a low pressure round without a lot of powder behind it. You will be in permanent hearing damage territory.
Then add in muzzle flash. If your chosen ammo can make you see spots in an indoor range, imagine what it can do when you are half awake and in the dark. Those wonderful loads of Blue Dot that you have fun with at the range will be blinding at night. When I go to the desert for some R&R, I like to practice some night fire; especially when there are Noobs present. My SP101 3" with 125 gr. pills behind a suitable dose of W296 are real attention getters. You get 2-4 feet of bright flame out the front and about a 1 foot cylinder gap flash out the sides. It pretty much matches my SBH 7 1/2" with 240 gr. loads. You would also be surprised what several popular semi auto loads produce. My 12 ga. 20" with 3" mag.s has been described to me as squeezing a bright orange beach ball out of the muzzle. Personally, I blink when I squeeze at night so I'm not blinded like the rest of them.
If possible, I recommend some night fire / low light exercises so you understand what you are bound to experience. As to hearing loss; personnaly I can deal with that. If I am alive and the threat is neutralized; that to me is an acceptable trade off. You may not have time to put glasses on, muffs on, get your gun, and get ready. Remember, you may be awakened by someone coming in your bedroom window.
The picture is one frame from a P&S camera video but it should shed some light on night time muzzle flash.