308 Winchester 16” v 20” barrel length noise question

[mavracer]

compare the noise and fireballs

Noise and fireballs aren't necessarily a 1 to 1 ratio.

albeit done with 556 is in line with what you suggest and with what I've read elsewhere. Not to say that a 16" 308 isn't loud and blasty, but that the numbers being used to describe it aren't right. 20dB would be 100X the energy (louder).

Yeah that study looks more inline with most of the meter testing I've seen.
Looking at his testing on the difference between 14.5 and 20 inch 5.56 and then looking at this chart on muzzle devices.
What you screw on the end will make way more difference than a couple inches of barrel.

 

[Dr T]

An issue is in the perception is not with the math, but how the sensor systems work. Human senses tend to work on a logarithmic scale and Decibels are a Ratiometric scale. If A is twice the size of B, then 3 dB = 10 LOG10 (A/B) which is 10 LOG10 (2). And "twice as loud" does not mean that the sound pressure is twice as high; it means that the Human PERCEPTION of the loudness is twice as high I think that this is because the cochlea is a logarithmic spiral. (But, I can be wrong and often am).

Back to the OP's Question. For years I hunted with an uncompensated Ruger 77 Frontier in 308 (16.5" barrel). I also have another bolt gun in 308 with a 22" barrel. In open air hunting and range situations, I don't recall the Frontier as being significantly louder. However, I certainly have no issue with the observations that a compensated semiauto 308 will be significantly louder with a 16" barrel. Also, I find that guns with Stoner semiauto actions are much louder than bolt guns (all of those moving parts).

However, this is a YMMV issue. For example, I have a Ruger Security 6 with a 6" barrel in 357 Magnum (uncompensated), and a Taurus 357 Magnum with a 4" barrel and a built-in compensation that is tilted slightly forward. I find the Ruger is significantly louder with full power 357 Magnum loads.

 

[DustyGmt]

It's weird how much a 2"-4" difference can make in sound, at least perceived sound. The Socom M1A 16" vs the Scout M1A 18", seemed to me to be completely different. The Socom seemed to pop you right between, behind the eyes and get your nasal passage whereas the scout, while not quiet by any stretch was much more pleasant to shoot.

I've heard that an 18" bbl .308 is pretty much maxed out and anything between 18" and 22" is pretty much negligible, but that the 18" is better by leaps and bounds than the 16". Dunno how much truth there is to it, not a load data ballistician or expert by any means, don't have a chrono so my $0.02 cents aint worth a penny....

I know the 18" .308 is definitely alot more blasty and recoil harder than a 22".

 

[Walkalong]

I don’t want a .308 any shorter than 20”, shorter than that isn’t any handier to me.

 

[mavracer]

It's weird how much a 2"-4" difference can make in sound, at least perceived sound. The Socom M1A 16" vs the Scout M1A 18", seemed to me to be completely different.

Yeah probably nothing to do with the SOCOM having a muzzle brake

 

[TonyAngel]

My basic understanding of how the human ear perceives changes in volume stems from my teenage years when having a loud sound system was cool.

As I understand it ... given any level of volume, the volume level must be increased by 3db in order for the human ear to perceive a change in the volume level. In order to obtain that 3db increase, you have to double the power. For example, upgrading from a 50 watt Amp to a 75 watt Amp won't get you anything in terms of max volume. You have to go from 50 watts to 100 to be able to perceive the difference. This is represented by the display on some amplifiers that will show their output on a scale of something like 1.5 ...3...6...12, etc as a representation of what the Amp is putting out at any given moment.

Still, this whole argument is largely academic. The shorter barrel is going to be louder than the longer barrel. I'd go with the shorter barrel because it makes the rifle easier to deal with and it looks cooler, unless you NEED the velocity. How offensive it will be depends on the muzzle device you use and whether your friends are real shooters.

 

[DustyGmt]

Yeah probably nothing to do with the SOCOM having a muzzle brake

Forgot about the brake on the Socom but thanks , I had the Scout for some years, only Socom I ever had an experience with was the guy next to me had the Socom and was just shooting fast and stupid and obnoxiously to my left. Was just cranking the dials on the rear sight with no rhyme or reason, I just remember thinking that sum'bxxxx is loud as heck....

 

[silicosys4]

I have 16" SFAR,
18" M1A scout,
20" LFAR,
22" bolt rifle.

Its the muzzle device that makes the first two obnoxious to anybody standing beside the shooter. The noise difference to the shooter is negligible through muffs or plugs, but the concussion from those short barrel .308 rifles with muzzle devices sucks.

Yeah probably nothing to do with the SOCOM having a muzzle brake

The 18" scout squad has an obnoxious brake on it too. If anything its more aggressive and obnoxious than the SOCOM

 

[mavracer]

The 18" scout squad has an obnoxious brake on it too. If anything its more aggressive and obnoxious than the SOCOM

It's really not since it doesn't have any kind of restriction at the end to make an expansion chamber to force the gasses out of rhe ports like the SOCOM brake has.

The SOCOM brake has a smaller exit diameter making an expansion chamber to force more gas out the ports.

 

[citizenconn]

The most offensive I've heard are AR pistols with 7-10" barrels.

For me particularly the ones in .223/5.56. My .300 Blks, .350 Legends, .450 Bushmasters, even 6.5 Grendels in short barrels are not nearly as loud and that is with me using brakes on all of them.

 

[mavracer]

For me particularly the ones in .223/5.56. My .300 Blks, .350 Legends, .450 Bushmasters, even 6.5 Grendels in short barrels are not nearly as loud and that is with me using brakes on all of them.

Yep the more over bore a round is and the higher the operating pressure is the more muzzle pressure you'll have

 

[bbqncigars]

The brakes on my fifties have a blast area about thirty to ninety

degrees to either side of the bore axis. Most lighter stuff will get displaced within that area. The chrono display in the picture is just on the edge of the area.

 

[Roverguy]

16” 308 is silly and obnoxious.

 

[silicosys4]

It's really not since it doesn't have any kind of restriction at the end to make an expansion chamber to force the gasses out of rhe ports like the SOCOM brake has.
View attachment 1161478
The SOCOM brake has a smaller exit diameter making an expansion chamber to force more gas out the ports. View attachment 1161477

I've shot and been around both. They are both pretty obnoxious. The Socom is louder, imo, but the Scout is more "blasty", especially to the sides. Neither is as bad as the SFAR with the boomer brake.

 

[gotboostvr]

16” 308 is silly and obnoxious.

Not necessarily

 

[mavracer]

Not necessarily

I Agree

 

[gotboostvr]

I Agree
View attachment 1161664

How you like that Crimson Trace?

Looks like they're only making lower budget stuff now, but I really like my 4-20x on the Cross

 

[mavracer]

How you like that Crimson Trace?

Looks like they're only making lower budget stuff now, but I really like my 4-20x on the Cross

It's pretty nice not sure it's worth MSRP but I bought this series 5 1-8x and 3 of the 1-5X series 3s when Midway was closing them out for like 1/2 price.
I like the simple reticle and glass is very good.

 

[gotboostvr]

It's pretty nice not sure it's worth MSRP but I bought this series 5 1-8x and 3 of the 1-5X series 3s when Midway was closing them out for like 1/2 price.
I like the simple reticle and glass is very good.

Yeah I snagged mine during that sale too haha