Why suppress .308 or 7.62x51 guns?

[Deleted member 67409]

Besides the "I want to" or in other countries where a suppressor is considered the best way to be a polite shooter or hunter.

The round is very supersonic, so how much does a suppressor actually suppress on a .308?

 

[308rifleman]

Besides the "I want to" or in other countries where a suppressor is considered the best way to be a polite shooter or hunter.

The round is very supersonic, so how much does a suppressor actually suppress on a .308?

It will diminish the muzzle blast and alter the sound of rifle's report. Unfortunately, like you mentioned, the supersonic "crack" of the projectile would remain an issue. You would need subsonic ammo to get the full benefit of a suppressor.

 

[Randy Lahey]

If you want it quieter, there is sub-sonic .308

 

[Deleted member 67409]

If you want it quieter, there is sub-sonic .308

Yeah but how effective is subsonic .308? The speed of sound is around 1125fps. You'd effectively be shooting something with the power of .32-20 but with a spitzer bullet. Do subsonics even function in semi autos?

 

[Golddiggie]

Yeah but how effective is subsonic .308? The speed of sound is around 1125fps. You'd effectively be shooting something with the power of .32-20 but with a spitzer bullet. Do subsonics even function in semi autos?

For function, that's why they have adjustable gas systems for AR10s.

 

[Randy Lahey]

Yeah but how effective is subsonic .308? The speed of sound is around 1125fps. You'd effectively be shooting something with the power of .32-20 but with a spitzer bullet. Do subsonics even function in semi autos?

Looks like there are a few different bullet offerings in sub-sonic, but of course they will all have less power. Might have to adjust the gas block or recoil springs to get it to function reliably in a semi-auto. I’m curious about it myself.

 

[one-eyed Jack]

In our family we have a Stag AR in 6.8 SPC with a Gemtech "Tracker" can on it. Used for hunting. It tones down the muzzle blast pretty well. For plinking we have the adaptor to mount it on the 5.56 upper. Why not quiet things down a bit? Jack.

 

[Dradian]

While 308 isnt silent when suppressed, it still cuts down on a lot of blast. makes long range sessions a lot more enjoyable

 

[ChevyGuy91]

Suppressing any super sonic rifle round is still going to be loud. Why do it? For the reason you'd suppress a 556 gun, sound reduction and flash elimination.

 

[ChevyGuy91]

Also, don't mess with subsonic 308 unless it's in a bolt gun, and even then, Discreet Ballistics is about the only load I'd bother with.

 

[Deleted member 67409]

Suppressing any super sonic rifle round is still going to be loud. Why do it? For the reason you'd suppress a 556 gun, sound reduction and flash elimination.

A flash suppressor is a much cheaper way to eliminate flash. What percentage of noise reduction is possible on a .308 semi-auto? 25%? 30%?

 

[M1911]

My understanding is that military snipers often suppress 7.62 because it makes locating the sniper harder. The report from the rifle is directional and the suppressor reduces that. The supersonic crack from the bullet travels out from the path of the bullet, not back to the sniper.

 

[Picton]

My understanding is that military snipers often suppress 7.62 because it makes locating the sniper harder. The report from the rifle is directional and the suppressor reduces that. The supersonic crack from the bullet travels out from the path of the bullet, not back to the sniper.

I heard bullets go cracking past a few times. I had a definite sense where they were coming from, even without other evidence.

I could’ve been wrong, of course. I’ll never know. But I think I was right.

 

[M1911]

I heard bullets go cracking past a few times. I had a definite sense where they were coming from, even without other evidence.

I could’ve been wrong, of course. I’ll never know. But I think I was right.

That was not my experience when in the butts at a rifle range. The crack going overhead came from above, with the thump from the rifle report following just a fraction of a second later. The thump from the rifle report was directional.

 

[Picton]

That was not my experience when in the butts at a rifle range. The crack going overhead came from above, with the thump from the rifle report following just a fraction of a second later. The thump from the rifle report was directional.

But you’re in a trench in the butts.

That might make some difference. The first time I heard a bullet crack past for reals, there was a group of four of us. We all looked in the same direction, and when we discussed it later we all agreed on where we thought it came from. I had a very vivid sense of where it flew, how far away it was from me, and its direction of travel.

No flash, no report. The dude shot high and left, fortunately.

 

[ChevyGuy91]

A flash suppressor is a much cheaper way to eliminate flash. What percentage of noise reduction is possible on a .308 semi-auto? 25%? 30%?

A flash suppressor doesn't do much if you have night vision on.

Noise reduction? Idk, I'm not a suppressor nerd, but any can worth a shit is going to take a bare muzzle from 160+db to roughly 140 or so. It is significant enough that I don't like shooting rifles with out cans anymore.

 

[Davidk]

I shoot all my bolt guns suppressed with no hearing protection.

 

[ChevyGuy91]

I shoot all my bolt guns suppressed with no hearing protection.

Bolt guns all day long. If I'm just cracking a few shots on an open range, I'll shoot my ARs without ear pro. Any more then that, and I wear my over ear protection.

 

[Deleted member 67409]

A flash suppressor doesn't do much if you have night vision on.

Noise reduction? Idk, I'm not a suppressor nerd, but any can worth a shit is going to take a bare muzzle from 160+db to roughly 140 or so. It is significant enough that I don't like shooting rifles with out cans anymore.

140 / 160 = 0.875, about a 12.5% noise reduction. Hearing safe is approximately 85dB.

 

[308rifleman]

My understanding is that military snipers often suppress 7.62 because it makes locating the sniper harder. The report from the rifle is directional and the suppressor reduces that. The supersonic crack from the bullet travels out from the path of the bullet, not back to the sniper.

If the sniper does his job correctly, the enemy combatant will be on the ground, dead in a pool of his own blood, before he hears the ballistic crack of the bullet that killed him.

 

[Dradian]

140 / 160 = 0.875, about a 12.5% noise reduction. Hearing safe is approximately 85dB.

not exactly. Gunshot hearing safe is around 140 for limited exposure.

Also, Dbs are logarithmic not linear. 140db is significantly quiter than 160.

I think it is every 3db increase is double the volume. so 20 db would make it 6 times louder? I'm sure someone here can correct me.

edit: I had to look it up. It is every 10dbs sounds twice as loud. so 140 to 150 is double, then 150 to 160 is double again.

 

[one-eyed Jack]

If the sniper does his job correctly, the enemy combatant will be on the ground, dead in a pool of his own blood, before he hears the ballistic crack of the bullet that killed him.

Also, the deer. Jack.

 

[Davidk]

If the sniper does his job correctly, the enemy combatant will be on the ground, dead in a pool of his own blood, before he hears the ballistic crack of the bullet that killed him.

The benefit of the suppressor to the sniper is not in regards to his target, its toward the other enemy. The suppressor eliminates the flash and the sound signature is scattered, so the sniper's position is not given away.

 

[M1911]

If the sniper does his job correctly, the enemy combatant will be on the ground, dead in a pool of his own blood, before he hears the ballistic crack of the bullet that killed him.

Yes, but what about his six buddies?

 

[ChevyGuy91]

140 / 160 = 0.875, about a 12.5% noise reduction. Hearing safe is approximately 85dB.

If you don't want a suppressor, don't buy one. Those of us that have them, use them, and understand them, enjoy and buy them.

 

[7OGlock]

140 / 160 = 0.875, about a 12.5% noise reduction. Hearing safe is approximately 85dB.

No, logarithmic, it’s a 20db change, which is 10^(20/10) = 100 x increase from 140 to 160. So going from 160 to 140 is a 99% decrease in sound pressure I.e. “substantial”

 

[whacko]

Besides the "I want to" or in other countries where a suppressor is considered the best way to be a polite shooter or hunter.

The round is very supersonic, so how much does a suppressor actually suppress on a .308?

I fired an internally suppressed ar10 up at camp Jericho Vermont a few years back. No ear pro needed at all. Yes there was an audible crack but not needing ear pro was cool. Was quieter than a 22lr. We were engaging targets at 600 to 800 meters. I assume at that distance it would be very difficult to tell where the shot came from. So it has a military application for sure. Plus where legal to suppress a gun when hunting ......it don't piss off the neighbors.

 

[Deleted member 67409]

If you don't want a suppressor, don't buy one. Those of us that have them, use them, and understand them, enjoy and buy them.

A suppressor is a minimum $500 + $200 +/- investment on top of the price of a gun, an optic, an optic mount, extra magazines, etc. Not including other costs like setting up a NFA trust. That's why I want to understand the math behind suppressor noise reduction. A 12.5% decrease in noise reduction is pretty marginal in comparison to the amount of money spent on a suppressor and could better be invested in better hearing pro. But a 99% noise reduction, like @7OGlock said, is clearly worth the money.

 

[one-eyed Jack]

A suppressor is a minimum $500 + $200 +/- investment on top of the price of a gun, an optic, an optic mount, extra magazines, etc. Not including other costs like setting up a NFA trust. That's why I want to understand the math behind suppressor noise reduction. A 12.5% decrease in noise reduction is pretty marginal in comparison to the amount of money spent on a suppressor and could better be invested in better hearing pro. But a 99% noise reduction, like @7OGlock said, is clearly worth the money.

On the other hand, with adaptors, a single can will work for several guns. You can also build your own. Jack.

 

[7OGlock]

But a 99% noise reduction, like @7OGlock said, is clearly worth the money.

Just a quick search found this, which seems reasonably clear:

http://www.idc-online.com/technical_references/pdfs/electronic_engineering/What_is_a_Decibel.pdf

To be fair though, 140 is still extremely loud:

https://www.osha.gov/SLTC/noisehearingconservation/loud.html