You are in a fight for your life and worried about your hearing?

 

Or he is preparing well in advance so in a “fight for your life” he hopefully wins AND doesn’t accrue any hearing damage.

 

I shoot 115 to 147s, although I prefer 124s. No sound difference out of a 5"

 

Like I said….more of a mental learning exercise than anything.

This is what happens when bored engineers start pondering ballistics and ammunition choices.

I’d rather be deaf than dead….

But…

If 147 HSTs were a few decibels quieter than 124 or 115 (with decibels being logarithmic), I would consider that in future purchases.

That’s what I would consider a “free lunch”. A benefit with no extra cost.

 

I have not measured to see if there are differences due to bullet weight. I have shot suppressed outdoors without hearing protection and found my cans are quiet enough with all 9mm, 38 super, 223 and 300bo weights and with 45acp to be hearing safe. The noticeable difference is supersonic rounds will have the supersonic crack and subsonic will not. That Crack happens downrange and is hearing safe outdoors.

147 grain 9mm exerts more force on the slide and will start to over cycle a short slide sooner than 124 and 115gr will. So no 147 is not better for a shorter gun.

 

I have not measured to see if there are differences due to bullet weight. I have shot suppressed outdoors without hearing protection and found my cans are quiet enough with all 9mm, 38 super, 223 and 300bo weights and with 45acp to be hearing safe. The noticeable difference is supersonic rounds will have the supersonic crack and subsonic will not. That Crack happens downrange and is hearing safe outdoors.

147 grain 9mm exerts more force on the slide and will start to over cycle a short slide sooner than 124 and 115gr will. So no 147 is not better for a shorter gun.

.223 and .38 super can never be hearing safe. Non-subsonic 300 black and 115 and 124gr 9mm can never be hearing safe. The supersonic crack is happening behind the bullet as soon as it uncorks from the bore, not just down range. 147 is generally more quiet than any 115 or 124gr. Just because it's listed as 147 and subsonic doesn't mean it's what you want though. Some are loaded for a good competent fpe and will almost always crack. Others are 50/50 despite being listed as subsonic. Then other ammo is mouse fart quiet but has only .380 energy.
No matter if you run a fixed barrel blowback or a slide gun with a booster there will be some tuning depending on what ammo you run. Powders and burn rates can be changed and the good quiet stuff isn't putting anywhere near the forces on a slide that standard ammo would.
Exposure to just 110 decibels for longer than 60 second intervals is enough to cause permanent irreversible damage. The chance for instant permanent harm(from a single shot) starts at 120db.

 

I think it's more than a few db's, most 9mm is around 160 db's where as 147 sub sonic is around 130 db's but in a closed area I'm not sure you would tell the difference.

Sub sonic has the largest impact when supressed

 

Do you have data to support that. That would make it hearing safe without a suppressor. The charts I can find do not break down the bullet weights. It just claims that they are relatively the same for a given cartridge size. The lower end being 150dbs for 25acp.

Very hard to believe 147 gr could be 30dbs lower.

Twice as loud is consider to take a 10db increase.

 

Ok found an article that listed what ammo they tested with. Looks like they tested 115, 124 and 147. The range was 165-167 from a glock 19. It did drop near 30dbs when suppressed. Could that be the 130db number you speak of John?

Silencer Guide with Decibel Level Testing

A Complete Silencer Guide: silencers vs. suppressors, laws involved to buy one as well as field testing to compare noise levels when using a silencer.

www.ammunitiontogo.com

 

Regardless of suppressed or not the crack would be at the same decibel level. The chart above shows 25db-30db drops when testing the same gun and same ammo both suppressed and not suppresses. That drop still occurs even with supersonic ammo. Like I said the crack is not loud. On the location of the crack I was wrong. A search shows why I thought it was happening down range as the info suggests the crack is not locatable. Same info suggested that some are tolerant of said crack and some are not.

 

Why not just run a can on your HD gun, pick ammo based on effectiveness and penetration, have electronic ear pro on standby to give you super hearing and protection, and even a plate carrier if you have time.

 

You can not hear the difference between 9mm 115gr, 9mm 124gr, 9mm 147gr in a gun fight.

This being said, get the 147gr HST if you think you will get a silencer.
AND If you are buying personal protection ammo, don't buy 1 box. BUY A PILE OF WHAT YOU LIKE. You don't want just one box and then have to test a different box and then change brands and then ..... You are much better off to buy a box, test and then buy a pile of the same lot because you know it runs in YOUR gun.

 

Here is a real life experience with 9mm being fired inside. I had a customer discharge his pistol inside the shop.

Glock 43
115gr 9mm FMJ

Open floor plan, ceiling about 9’ high.

I was standing beside him when it happened. No loss of hearing, and no ringing of my ears. The customer across the shop in another room thought someone drop something on the floor.

Like other people already mentioned, in a self defense situation you will never hear the gun, unless you train for it. Too much adrenaline.

What you should be more worried about is over penetration. That 115gr bullet went through 2 sheets of drywall, insulation, a refrigerator, 4 bottles of Gatorade, and finally stopped in a quarter panel of a vehicle. It traveled over 20ft going through stuff.

Just my 2 cents