165dB is *extremely* loud. It was a guess based on the cartridge (a magnum round) but its probably a bit high at the ear (since it was a 26" bolt gun its likely closer to 150-160 at the ear).
My audiologist said long duration lower dB noise is riskier because there is no pain response. Its similar to lasers. A high power green laser (within reason) will cause less or no damage then a much much lower powered IR laser because your eyes natural protection reflexes kick in and its painful (so you avoid it). While the IR laser you could just stare at and your vision would slowly degrade (or quickly degrade, depending on intensity)The same goes for noise.
A single loud rifle shot *hurts* and makes you jump or flinch and usually causes you to do *something* to avoid it repeating. But we actively subject ourselves to very loud music willingly and for much longer durations. If a rifle is say 130dB for 2 ms each shot then I need to shoot 500 rounds to reach 1 second of exposure. While a lower dB noise might go unnoticed in a work environment for minutes or longer.
I have another example from personal experience (honestly its impressive my hearing is as excellent as it is considering). I went to an indoor skydiving place and had an earplug pop out during the flight without noticing. It was 15-20 minutes at more than 100dB im sure (your essentially jumping over an aircraft engine in a stream of 100+ mph wind so wind noise is intense). My ear was numb and ringing for *days*. I had a noticeable loss of hearing in that ear for about 4 days. I got in to see the audiologist about 2 weeks later and my ears measured fine with no residual issues. Had that ear plug falled out during a shooting match id have immediately stopped and DQed. It would have been fairly unpleasant to continue while with the skydiving I didnt even notice it missing until it was over.
Regardless, the advise is the same. Don't exposure yourself to intense sound pressures of even short durations, and just because it doesn't "hurt" doesn't mean its not causing permanent damage. I've met plenty of people with cumulative hearing damage and a only a few with acute damage (like the article is referring too) but it's a significant quality of life issue. Saying "huh?" Or "what?" All the time is embarrassing for people and can significantly impact your enjoyment of day to day life.
So off topic, but if your in America make sure you tell your congressmen/senators that silencers/suppressors are not the tools of assassins, their legitimate safety devices that are outright required in some european ranges to reduce noise pollution and for the safety of the range officers who work there. They should require a 200$ fee and months or years of administrative delays to buy one. Their use should be encouraged not discouraged.
There is a reason the militaries new rifle (the M5) looks like it will be issued with a standard noise suppressor equipped.