Ok guys, you are all correct insofar as understanding the more internal volume a moderator/suppressor has, the greater air/gas it can displace before the pellet/bullet exits the muzzle. That displaced/temporarily-absorbed and/or slowed pressure, be it air from an airgun or gases from a powder burner, is released with a whoosh...if you will, rather than the sudden blast you obviously get when said pressure is at suddenly released full-on-purge into the atmosphere from the muzzle of an unsuppressed weapon. Suppressors, when used on firearms also serve as most excellent flash hiders, because...since the gases are slowed way down prior to release, there's not as much burn remaining to exit the suppressors terminal end when the projectile exits.
So, what you're asking is length vs girth for effectiveness right? It's not really length vs volume, or girth vs volume...because adding more of either, adds volume; and, the more USEABLE volume you have...the more pressure you displace, therefore the quieter the moderator/suppressor...but, as someone previously stated here in...a 6" diameter unit that is 1" in length wouldn't likely work very well, and that was exactly right.
What you have to do is realize what's going on INSIDE that unit, after the trigger is pulled on a LOADED weapon; and, really, all you have to do is slow it all WAY, WAY, WAY down in the minds eye to understand this. In a properly vented and/or baffled unit...the first few, and the last, baffle may be vented for enhanced effect but this all depends on the guns caliber, velocity, etc. As the projectile enters the first "decompression chamber," if you will, said chamber...the space between the entrance of the unit and that first baffle, is pretty much instantly pressurized. Second chamber...between the first and second baffle, more pressure is displaced and so on & so on.
For this reason, longer suppressors are way more effective than shorter suppressors, especially if there's bleed-back venting here and there. The reason, is that the projectile spends more TIME in the longer unit, and therefore has the chance to bleed off more pressure before entering the atmosphere at the units terminal end.
That's why, essentially, a unit with say that previously noted (6" diameter & 1" length), would be useless, the projectile would exit into the outer atmosphere faster than that 6" diameter could even fully pressurize, displacing sufficient pressure to make a difference. With the 1" length and say a single exit disk at the terminal end...no intermediate baffle, the rest of that pressure is easily going straight out that short passage length and into the outside atmosphere...with a bang.
So, if you compare two units, volume being the identical, but one longer and one of a larger inside diameter, the longer unit will be more efficient at striping, decompressing/displacing more pressure before the projectile exits the unit.
There is SO much to this subject-(or that's been the case with powder burner experience and...it's all the same relative physics just much less pressure in the airgun field), bleed back/vented baffles, unvented baffles, where to place which type, spiral unicore/single piece billet baffling systems, terminal endplate venting vs non vented terminal endplate use, etc., etc., etc., I could go on for days...but, yes, the more volume the better, and that volume is more efficiently/effectively represented in length vs girth, all other physical aspects being the same. Then there's the Hollywood crap where you see a four inch suppressor with a 2-1/2" diameter on a handgun and, to top it all off, it's a .38 S&W Special or .357" REVOLVER. I just couldn't resist bringing that up. We all know the gap at the cylinder-face and the forcing cone of the revolver prevents fully effective suppression of a revolver...with the exception of the Russian Nagant with the cylinder which cams forward over the forcing come with each ridiculously difficult cocking of the hammer...besides, that same short fat suppressor wouldn't do much of anything on say a 1911 in .38" Super. Just too much pressure, too much bore diameter, and not enough decompression time in the short tube. Another thing...but this manifests itself only in powder burning semi auto weapons. You almost always must reduce the recoil spring pressure if you want to maintain semi auto function on a truly quiet weapon, because...unless the weapon is a handgun that is already utilizing a sub sonic round....45 ACP, .380 ACP, you'll have to handload, down-loading to reach a subsonic velocity, or purchase readily available subsonic ammo, in order to prevent the downrange crack that occurs when the bullet breaks the sound barrier. The exception to this rule is that, if the round is specifically designed for this use...as inn the .300 Blackout...where you maintain chamber pressure and thus a working slide or jolt in semi auto...just by buying ammo with the higher grain wt projectile...keeping pressure up and dropping velocity into subsonic or just transonic, depending on the load.
I know you guys have all had a break barrel that would crack like a .22 LR when using polymer rounds or 7.9's or 8's in .177" but would go almost silent less the muzzle report when you used 10.5 gr stuff. So, especially with the hpa/pcp guns like my modded Talon-P carbine, my Escape, the Condors, and some other really fast airguns that we are seeing today, DEPENDING on how quiet you want it to be, projectile choice and/or pressure-(velocity)- regulation, are all things to consider.
First time I've posted here by the way, new member, long time shooter and Smith of just about anything that can take game or defend the home front. I saw this thread and felt I had to join in. Share some experience.
I hope everyone had a wonderful Thanksgiving.
Thank you.
So, what you're asking is length vs girth for effectiveness right? It's not really length vs volume, or girth vs volume...because adding more of either, adds volume; and, the more USEABLE volume you have...the more pressure you displace, therefore the quieter the moderator/suppressor...but, as someone previously stated here in...a 6" diameter unit that is 1" in length wouldn't likely work very well, and that was exactly right.
What you have to do is realize what's going on INSIDE that unit, after the trigger is pulled on a LOADED weapon; and, really, all you have to do is slow it all WAY, WAY, WAY down in the minds eye to understand this. In a properly vented and/or baffled unit...the first few, and the last, baffle may be vented for enhanced effect but this all depends on the guns caliber, velocity, etc. As the projectile enters the first "decompression chamber," if you will, said chamber...the space between the entrance of the unit and that first baffle, is pretty much instantly pressurized. Second chamber...between the first and second baffle, more pressure is displaced and so on & so on.
For this reason, longer suppressors are way more effective than shorter suppressors, especially if there's bleed-back venting here and there. The reason, is that the projectile spends more TIME in the longer unit, and therefore has the chance to bleed off more pressure before entering the atmosphere at the units terminal end.
That's why, essentially, a unit with say that previously noted (6" diameter & 1" length), would be useless, the projectile would exit into the outer atmosphere faster than that 6" diameter could even fully pressurize, displacing sufficient pressure to make a difference. With the 1" length and say a single exit disk at the terminal end...no intermediate baffle, the rest of that pressure is easily going straight out that short passage length and into the outside atmosphere...with a bang.
So, if you compare two units, volume being the identical, but one longer and one of a larger inside diameter, the longer unit will be more efficient at striping, decompressing/displacing more pressure before the projectile exits the unit.
There is SO much to this subject-(or that's been the case with powder burner experience and...it's all the same relative physics just much less pressure in the airgun field), bleed back/vented baffles, unvented baffles, where to place which type, spiral unicore/single piece billet baffling systems, terminal endplate venting vs non vented terminal endplate use, etc., etc., etc., I could go on for days...but, yes, the more volume the better, and that volume is more efficiently/effectively represented in length vs girth, all other physical aspects being the same. Then there's the Hollywood crap where you see a four inch suppressor with a 2-1/2" diameter on a handgun and, to top it all off, it's a .38 S&W Special or .357" REVOLVER. I just couldn't resist bringing that up. We all know the gap at the cylinder-face and the forcing cone of the revolver prevents fully effective suppression of a revolver...with the exception of the Russian Nagant with the cylinder which cams forward over the forcing come with each ridiculously difficult cocking of the hammer...besides, that same short fat suppressor wouldn't do much of anything on say a 1911 in .38" Super. Just too much pressure, too much bore diameter, and not enough decompression time in the short tube. Another thing...but this manifests itself only in powder burning semi auto weapons. You almost always must reduce the recoil spring pressure if you want to maintain semi auto function on a truly quiet weapon, because...unless the weapon is a handgun that is already utilizing a sub sonic round....45 ACP, .380 ACP, you'll have to handload, down-loading to reach a subsonic velocity, or purchase readily available subsonic ammo, in order to prevent the downrange crack that occurs when the bullet breaks the sound barrier. The exception to this rule is that, if the round is specifically designed for this use...as inn the .300 Blackout...where you maintain chamber pressure and thus a working slide or jolt in semi auto...just by buying ammo with the higher grain wt projectile...keeping pressure up and dropping velocity into subsonic or just transonic, depending on the load.
I know you guys have all had a break barrel that would crack like a .22 LR when using polymer rounds or 7.9's or 8's in .177" but would go almost silent less the muzzle report when you used 10.5 gr stuff. So, especially with the hpa/pcp guns like my modded Talon-P carbine, my Escape, the Condors, and some other really fast airguns that we are seeing today, DEPENDING on how quiet you want it to be, projectile choice and/or pressure-(velocity)- regulation, are all things to consider.
First time I've posted here by the way, new member, long time shooter and Smith of just about anything that can take game or defend the home front. I saw this thread and felt I had to join in. Share some experience.
I hope everyone had a wonderful Thanksgiving.
Thank you.
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