Does A Longer Barrel Reduce Noise Of Fired Shot?

[quneur]

Interesting topic. Since sound is just air pressure, the sound should correlate with the fps of the bullet exiting the barrel. Powder type, burn rate, bullet weight all effect fps and barrel length.

The atmosphere would also affect the sound. Less air would mean less intensity. As for the shooter, sound expands in a sphere so the closer to the point of origin (shorter barrel) the more pressure or louder one perceives the sound.

 

[rjmt]

Interesting topic. Since sound is just air pressure, the sound should correlate with the fps of the bullet exiting the barrel. Powder type, burn rate, bullet weight all effect fps and barrel length.

The atmosphere would also affect the sound. Less air would mean less intensity. As for the shooter, sound expands in a sphere so the closer to the point of origin (shorter barrel) the more pressure or louder one perceives the sound.

also your surrounding
if I'm shooting in an open field, my perception of the sound is less since there are no objects for the sound wave to bounce off of
a Ruger Rehawk with full power loads in a 7" bbl sends out a massive blast, but in our field with nothing to rebound off, it's comfortable to shoot without ear protectors, but shoot the same loads in the Forest and the concussion off the trees and overhead branches will kill your ears
when shooting my Garand early in the morning, my perception behind the buttstock is low sound, but I can hear the echo of the muzzle blast off the hills in the River Valley

 

[arakboss]

Interesting topic. Since sound is just air pressure, the sound should correlate with the fps of the bullet exiting the barrel. Powder type, burn rate, bullet weight all effect fps and barrel length.

The atmosphere would also affect the sound. Less air would mean less intensity. As for the shooter, sound expands in a sphere so the closer to the point of origin (shorter barrel) the more pressure or louder one perceives the sound.

Something I am interested in, is experimenting with using faster powders that will completely burn in the early stage of bullet travel through the barrel. This would likely lead to lower velocities but may also lead to quieter shots.

 

[Mike_M57]

also your surrounding
if I'm shooting in an open field, my perception of the sound is less since there are no objects for the sound wave to bounce off of
a Ruger Rehawk with full power loads in a 7" bbl sends out a massive blast, but in our field with nothing to rebound off, it's comfortable to shoot without ear protectors, but shoot the same loads in the Forest and the concussion off the trees and overhead branches will kill your ears
when shooting my Garand early in the morning, my perception behind the buttstock is low sound, but I can hear the echo of the muzzle blast off the hills in the River Valley

Yep. I've fired a .357 Magnum revolver at the beach out over the ocean. Sounds like a cap gun.

 

[rjmt]

Yep. I've fired a .357 Magnum revolver at the beach out over the ocean. Sounds like a cap gun.

you fired out over the ocean without a backstop? Isn't that dangerous to the Orcas
I think Jay Inslee passed an executive order against that

 

[teflon6string]

Just some food for thought...

In addition to lessening noise, a longer barrel can deliver higher muzzle velocity by making full use of powder burn (inside the barrel and behind the projectile), but only to a certain degree. Once powder is fully burned, any remaining barrel can actually scrub speed off of the bullet.

I forget the exact numbers, and it varies by caliber/load, but muzzle velocity for .45acp (for instance) tends to increase with barrel length only up to about 16 inches. Beyond that, all the powder has burned and any remaining barrel will introduce drag.

Experts with measuring equipment and access to multiple weapons/ammo can speak to the specifics.

 

[Provincial]

So with a long enough barrel, Mini-Mags can be subsonic! Cool!

 

[rjmt]

for those who have never fired an Mosin M38, a standard Mosin 91/30 has a 28" bbl - ammo and powder designed for this length
a Mosin M38 has an 18" bbl
mull that over in your mind for a while

View attachment 1249596

the above photo is an M38 with Russian military ammo
last night I fired an LVE commercial 200 grn hunting load out of my M38 - in the dark
acceptable recoil and minimal muzzle flash, even out of the 18" bbl
didn't loose my night vision
with modern powders, the 7.62x54R is a controllable load in these short carbines
I can't see a need for a bear rifle where I live, but if needed, the open sight M38 would be it!!
weighs only 7.5 lbs (about the same as an M4 with 30 rnd mag) and the power of a 30-06 with 200 gn ammo

the Russian's and indigenous Alaska people have been using these on Polar Bears for generations

 

[ma96782]

A simple experiment.

Stand next to someone firing a M91/30 Mosin Nagant rifle.
Then, stand next to someone firing an M44.

It's the same rifle and same cartridge.....though one has a shorter barrel. Yeah...and also check out the fire ball.

Aloha, Mark

 

[ilikegunspdx]

Just some food for thought...

In addition to lessening noise, a longer barrel can deliver higher muzzle velocity by making full use of powder burn (inside the barrel and behind the projectile), but only to a certain degree. Once powder is fully burned, any remaining barrel can actually scrub speed off of the bullet.

I forget the exact numbers, and it varies by caliber/load, but muzzle velocity for .45acp (for instance) tends to increase with barrel length only up to about 16 inches. Beyond that, all the powder has burned and any remaining barrel will introduce drag.

Experts with measuring equipment and access to multiple weapons/ammo can speak to the specifics.

Agree but it should be noted that optimum barrel length varies.

Note that frictional losses shooting 22lr subs or cb 22s in long barrels can actually prevent the bullet from leaving the barrel! I'm looking at you Aguila Colibri (POS ammo IMO).

 

[rjmt]

A simple experiment.

Stand next to someone firing a M91/30 Mosin Nagant rifle.
Then, stand next to someone firing an M44.

It's the same rifle and same cartridge.....though one has a shorter barrel. Yeah...and also check out the fire ball.

Aloha, Mark

I have a wide range of 54R ammo
it's not all the same - from 147 gn to 200 gn
Mil Surp, Barnaul and LVE ammo
new commercial ammo has different powders and ballistics
and your massive fire balls and window shaking concussions are gone with LVE ammo

 

[ma96782]

KISS.
A simple test does not include playing with ammo. Same ammo used....but two different platforms.

Did I really have to explain that?

Aloha, Mark

PS....as for the "fire ball". Sure.....ammo can be formulated with flash suppressants. Duh.

 

[rjmt]

now I bought some pre WW2 Turkish 7.92 Mauser ammo from a forum member

now, THAT will rock your World!!

when I shoot my Mauser M24, it registers as a "THERMAL EVENT" on the satellites

 

[rjmt]

KISS.
A simple test does not include playing with ammo. Same ammo used....but two different platforms.

Did I really have to explain that?

Aloha, Mark

must have been Mil Surp if you experienced fireballs out of an M44
did that only once out of my M38
I only shoot Barnaul 174 gn and LVE 200 gn out of my M38 now
Barnaul has a 203 soft point hunting load I need to try

 

[rjmt]

KISS.
A simple test does not include playing with ammo. Same ammo used....but two different platforms.

Did I really have to explain that?

Aloha, Mark

PS....as for the "fire ball". Sure.....ammo can be formulated with flash suppressants. Duh.

but if you want to impress the guys at the gun club, and light up your Rang Safety Officer, shoot a Mil Surp 147 gn from the '70s out of an M44

that ammo was loaded for the RPK and they didn't care about flash suppressants

sure - modern commercial 54R has flash suppressants - but what fun is that if your shooting at a gun club with a roof and baffles and shooter beside you

 

[ilikegunspdx]

Shorty 308s always give a pleasant glow of fireballness.

Is this video author a member here I wonder?

 

[Mike_M57]

you fired out over the ocean without a backstop? Isn't that dangerous to the Orcas
I think Jay Inslee passed an executive order against that

This was in California in the mid-80's. There was probably a bale of marijuana floating around out there as a backstop.

 

[rjmt]

This was in California in the mid-80's. There was probably a bale of marijuana floating around out there as a backstop.

that's how I got my Chinese Type 56 AK
back in '89, the Coast Guard chased down a Chinese freighter and they dumped all these crates overboard
waterproof cases with type 56 drifted up on the beaches in Oregon for a week
I was down driving on the beach south of Gearhart and found this crate on the beach
that's my story and I'm sticking to it

 

[Flopsweat]

that's how I got my Chinese Type 56 AK
back in '89, the Coast Guard chased down a Chinese freighter and they dumped all these crates overboard
waterproof cases with type 56 drifted up on the beaches in Oregon for a week
I was down driving on the beach south of Gearhart and found this crate on the beach
that's my story and I'm sticking to it

So you got a floater.

 

[rjmt]

So you got a floater.

Poly Tech AKS from factory 386 were only imported for one year and never sold by any dealer in Oregon
how else would I get one?