Home Forums Hunting & Shooting Ask The Gunwriters Do different powders create differen noise levels?

You could take someone's eye out swinging that thing around

Hey filaman,

It might have an effect on "felt" recoil but it hasn't got much to do with mechanical recoil. By felt recoil, I mean you might "feel" or believe (big flash, maybe) it's affecting you more when in reality, it's not doing anymore than any other load of the same recoil energy level.
Mechanically, that jet doesn't rely on the atmosphere. If that were the case, spacecraft wouldn't function very well in space since their exhaust wouldn't have anything to push against. Instead, it's all about Newton's Third Law. Others above have already alluded to it so there's no need to rehash it here.
I also agree, exit pressure at the muzzle, the direction of that exit pressure (specific brake), the nature of the expansion wave play (what kind of "flashhider/thing on the end") or even the sheer volume of the pressure wave (artillery/tank) will play the biggest role in how loud something is or perceived.
Additionally, whether the shooter has good hearing or is partially deaf plays an important role. 😁

I’ve had several guys in our club tell me that my 35 Whelen has a distinctive sound.

As do AK 47s. Ask me how I know.

Semper Fi

Same deal with my wife when I was using a .338 Winchester Magnum with a 22-inch barrel to slay whitetails along a certain Montana creekbottom 30+ years ago. She would be sitting a few hundred yards away, and sometimes not only heard the bigger boom, but the thump of the bullet hitting the deer.

Dunno what all this means. Have killed a lot of big game, quite suddenly, with cartridges that made a lot less and (sometimes) more noise than that .338.

My 23 inch barreled 6.5x55 has, to me, a very distinctive sound, much different than the rifles either side of it on the capacity scale that burn the same powders.

There was a guy who used to shoot trap with us who would have, usually, one shell loaded with black powder every round of trap. It made a significantly different sound (as well as a big cloud of smoke.

It's not as simple as just muzzle pressure. Noise measurements are higher in the direction the barrel is pointing than from behind. Partly this is due to the angle the bullet's supersonic shock wave propagates. A German paper I found a while back points to pre-war modeling which assumes sound begins radiating once the front of a gas sphere formed by the muzzle exhaust slows to sub sonic. Said gas ball would be affected by charge weight, powder energy density and burning speed, expansion ratio, etc.

If your company or college has an ISO subscription, ISO CEN 17201-1 provides a way to estimate peak sound. I don't have access (too cheap to pay for it), but I'd be happy to read a copy you send me.

Hmm I was thinking of the barrel being a bell and pressure being how hard you strike it..
But the gas ball makes more sense...
After all a sonic boom is the air collapsing around where the plane was.
Right?



Interesting. So it is an oxygen limited exothermic reaction?

I should go back and read the quickload documentation for % charge consumed....

Smokeless powder is primarily cellulose, C6 H10 05, but in modern rifles pretty much burns up in the first few inches in front of the chamber. Or as I noted, all the powder that's going to burn will burn in that distance. How much burns (and how quickly) depends on the peak pressure, since progressive rifle powders are designed to burn most completely at a certain pressure.

IMR4895, for example, was designed to burn best at a slightly lower peak pressure than most newer powders, because it was primarily designed for the M-1 "Garand." Which is partly why a lot of older handloading information firmly stated the most accurate loads occurred at somewhat under "maximum" pressure: Hundreds of tons of the original military-surplus 4895 were used by a LOT of handloaders in the decades after WWII. Most of today's rifle powders, however, are designed to burn best at around 10,000 PSI more than IMR4895 (either the surplus powder, or today's newly produced IMR4895).

But with any of them, the oxygen content of the nitrocellulose is consumed long before the gas produced exits the muzzle. When the still very hot "oxygen-starved" gas exits, it re-ignites due to the fresh supply of oxygen. This produces muzzle flash, NOT still-burning powder granules.

This is exactly why my 1884 trapdoor Springfield .45-70 shoots very accurately with bullets in the 400-grain range and IMR-4895, yet results in a bunch of unburned granules, both in the barrel and out (which can be seen by laying a sheet on the ground in front of the muzzle). The pressure never gets anywhere near ideal for even IMR4895, but enough burns consistently to result in good accuracy. But despite that there's there's almost no muzzle flash, because the remaining powder granules are NOT burning--and the long barrel results in very little hot gas exiting the muzzle.

QL a computer simulation, which may or may not match reality, in varying degrees. This includes the percentage of powder burned.

I always thought that a shotgun had a hollow sound. I could hear the other hunters shooting across the valley on opening day for pheasants.

https://en.wikipedia.org/wiki/Helmholtz_resonance

http://hyperphysics.phy-astr.gsu.edu/hbase/Waves/cavity.html#c4

0.7" diameter = 0.5^2" area.
Barrel length = 36"
Volume = 18 ^3"
speed of sound = 343 m/s

Using this calculator and these assumptions, the average 12 ga barrel would have a resonance of 60 Hz.

For those of you in Rio Linda, it sounds like the milk jug band.