Pressure is conserved, or is it not? To PS or not to PS

[gedeon]

I have many stamps and the last one I bought was a Dominus SR circa '21, so I am a pre-PS testing buyer. It seems all suppressor threads are now peppered with PS info and there has been several nagging thoughts I have about the testing methodology.

1) Milspec ammo is loaded to pressure spec and handloaded ammo is dialed in for each particular firearm/barrel as well as projectile, etc. When it comes to say m193, not all m193 are created equal within the same box much less the entire universe of production. Isn't it accurate to assume that pressure variability within particular rounds would influence the test results?

2) Furthermore, let's assume that all rounds have magically identical pressure spec with no SD. Wouldn't all pressure be conserved and, all other things being equal in the firearm, can volume would determine sensor (non-ear) detectable pressure readings? It stands to reason that pressure is conserved, so we are only talking about can volume and exit pathways for the gas over linear time. IE - smaller volume = more pressure OR less air trapped/suppressed.

3) Via the "Ideal Gas Law", I do not see any particular variable to account for baffle efficiency (or less) to drive sensor-detectable (non-ear) pressure readings.

My hypothesis - Given the variability in experienced/heard sound quality, I tend to still lean toward can volume + experienced sound vs. stats because physics. At a minimum, particular ammo pressure variability will drive variability in PS-methodology testing.

TLDR - PS is blackbox snake juice.

Educate me. Thanks.

 

[SuperBoot]

lol, all this sounds like is some corner case bullshit for neckbeards to antagonize mfg’s with.

 

[brianf]

not a can designer but when using scientific methods/process for testing etc, you need as many static variables as possible

EX, using your particular comfort level for sound suppression means nothing to another consumer nor can it be correlated or validated to a future test

what if you have hearing degradation at the freq which the can is loudest/most powerful amplitude

while you find it comfortable, a person with "perfect hearing" find it uncomfortable and damaging to their hearing

very simplistic example..but that is why testing uses electronics not humans


side note, 99.9% of internal can design is done on solid works (or alike) with fluid dynamics/ FEA

in theory, each can in the same price point and same physical size should have the same performance...if not they are not using the optimal design or material or construction.

its not 1980 where some guy takes out the mill and welding cart and magically come up with a super quiet can

 

[mi223]

I have many stamps and the last one I bought was a Dominus SR circa '21, so I am a pre-PS testing buyer. It seems all suppressor threads are now peppered with PS info and there has been several nagging thoughts I have about the testing methodology.

1) Milspec ammo is loaded to pressure spec and handloaded ammo is dialed in for each particular firearm/barrel as well as projectile, etc. When it comes to say m193, not all m193 are created equal within the same box much less the entire universe of production. Isn't it accurate to assume that pressure variability within particular rounds would influence the test results?

2) Furthermore, let's assume that all rounds have magically identical pressure spec with no SD. Wouldn't all pressure be conserved and, all other things being equal in the firearm, can volume would determine sensor (non-ear) detectable pressure readings? It stands to reason that pressure is conserved, so we are only talking about can volume and exit pathways for the gas over linear time. IE - smaller volume = more pressure OR less air trapped/suppressed.

3) Via the "Ideal Gas Law", I do not see any particular variable to account for baffle efficiency (or less) to drive sensor-detectable (non-ear) pressure readings.

My hypothesis - Given the variability in experienced/heard sound quality, I tend to still lean toward can volume + experienced sound vs. stats because physics. At a minimum, particular ammo pressure variability will drive variability in PS-methodology testing.

TLDR - PS is blackbox snake juice.

Educate me. Thanks.

Are you an engineer by chance... yeah I thought so.

 

[hlee]

Are you an engineer by chance... yeah I thought so.

Being an engineer is like being a vegan. You don’t need to ask. They’ll let you know.

 

[b6graham]

is this still available? does it come in HUB?

 

[gedeon]

Are you an engineer by chance... yeah I thought so.

i wage war with money

 

[gedeon]

not a can designer but when using scientific methods/process for testing etc, you need as many static variables as possible

EX, using your particular comfort level for sound suppression means nothing to another consumer nor can it be correlated or validated to a future test

what if you have hearing degradation at the freq which the can is loudest/most powerful amplitude

while you find it comfortable, a person with "perfect hearing" find it uncomfortable and damaging to their hearing

very simplistic example..but that is why testing uses electronics not humans


side note, 99.9% of internal can design is done on solid works (or alike) with fluid dynamics/ FEA

in theory, each can in the same price point and same physical size should have the same performance...if not they are not using the optimal design or material or construction.

its not 1980 where some guy takes out the mill and welding cart and magically come up with a super quiet can

physics is not influenced by hearing loss. fluids are also not gasses. on a flow basis, the most efficient muzzle device would be nothing, or a blast shield, but a bare crown because that's what would let the most gas escape without resistance and minimal amounts of gas would be forced through the gas block and the receiver/action.

 

[roostercogburn98]

neckbeards

There’s a memo out, this term is offensive

 

[E. Bryant]

Mass and energy will be conserved. Pressure is not necessarily so, since one of the primary mechanisms of suppression is heat transfer from the discharge gases to ambient via the suppressor, and so the gas characteristics at entry will determine how the energy leaves the can.

Differences in ammunition will certainly cause measurable differences in free-field perturbation, although the effect on the human ear is not necessarily significant. Semi-autos make evaluation of these effects more difficult, since there is a secondary flow path through the ejection port, and the timing of the bolt opening will be affected by the pressure curve of the selected ammo.

 

[gedeon]

pressure = force applied to area
force = energy transfer

so pressure would still be conserved in the context of the same firearm, same cartridge and varying cans.

as far as i can tell, there is very little heat dissipation scholarship built into suppressors so far, but it stands to reason that an aluminum can would dissipate heat the fastest. for a variety or reasons, we know aluminum is generally an inferior can material for centerfire cartridges. if one was inclined, the energy lost to thermal conversion is possible but it's baked into the cake as far as a discussion of suppressors and, more specifically, whether or not PS is snake oil info/subscription.

 

[E. Bryant]

And I'm tapping out. Hopefully there's a self-proclaimed expert who wants to jump on this grenade.

 

[hlee]

And I'm tapping out. Hopefully there's a self-proclaimed expert who wants to jump on this grenade.

I took high school chemistry. P1V1=P2V2 only applies in a closed system. A bolt gun kinda-sorta approximates a closed system only until the bullet exits the muzzle of the barrel. Even then there is some amount of gas blow by. And all bets are off once the bullet gets to the suppressor. And, and anything semiauto might as well be considered an open system. So, those “ideal gas laws” can go in the trash.

 

[salks]

I put bullets in gun, gun goes bang. it's not that hard.

 

[Huskydriver]

There’s a memo out, this term is offensive

#reported

 

[iceng]

Aluminium is a good conductor of heat. Aluminium suppressors work for centre fires, I've done it, quite a bit.

Be aware they heat up WAY faster than anything else (stainless, steels, inconel, etc) and corrode way faster as a result also. Generally I only rated (past tense, I currently don't make them anymore) mine to bolt action only, no semi or whatever.

 

[Clayman]

whether or not PS is snake oil info/subscription.

Are you trying to say the waveforms and db(impulse and pressure) readings he posts are fake?

I'm not entirely sure what you're even saying/asking.

Are you trying to say that volume + exit aperture should be the only determination for pressure readings at the muzzle regardless of what the baffles are doing?

very little heat dissipation scholarship built into suppressors

You realize this is how suppressors work right?

They try to trap hot high pressure gasses and cool those gases. Slows, cools gases and dissipates energy.

I do not see any particular variable to account for baffle efficiency (or less) to drive sensor-detectable (non-ear) pressure readings.

You don't think baffle efficiency (it's ability to trap, cool and dissipate energy) has any effect on performance?