most quiet moderator in real life test ????

[BackStop]

Airgun moderator function is simple. Disrupt disperse, and delay flow of chairge air (baffles and volume accomplish this). Dispersing and delaying pressure release. The better these 2 are accomplished the better the result. Sound dampening material like felt can also be used to absorb some of the sound waves addtionally. As stated, this can also be aided by tuning the gun to utilize a smaller, higher pressure charge. Reason being that charge volume is going to be less, which means it is easier to disperse. Often this actually occurs inside the barrel before the mod even begins to do it's job.

In essence, using JUST enough air to obtain the desired fps without using more than is needed for the desired fps with any given pellet (projectile).

Also, I think it has been demonstrated that, as I think you are saying, this is accomplished best by a quick blast of high pressure air as opposed to a very slightly longer blast of lower pressure air. The latter seems to have more "unused" air discharged from the muzzle, wasting air and making a louder report from the muzzle. Once the pellet/slug leaves the barrel, any air leaving the barrel after that is waste and noisy.

For those people who want the most power and efficiency, tuning to the knee (3% less than max fps basically) is the optimum for any airgun. If power alone is essential, the efficiency is not even considered. If efficiency is the only factor, inconsistency of fps is the problem if you want accuracy. Of course, this all has to be balanced with the chosen pellet/projectile which may or may not like the most efficient setting(s). Have I missed anything? I probably did...

Anyway, moderators make the most difference with tunes that are not efficient. So, if you put one on your airgun and are happy that it "hushed" your airgun to your liking... you might want to look at the tune and efficiency of your airgun as it is presently tuned. You MAY have it set where you want for power, but if you can accept lower power, you can have a MUCH quieter airgun, but you will still need a moderator if you fall into this power range if you want a "quieter" airgun. (grin)

Accuracy/precision is more important than power.

JMHO

Please correct me if I am wrong.

 

[Long_Gun_Dallas]

Pretty much dead on, I would jsut add that whether a projectile "likes" certain settings is pretty complex. This CAN be determined by a combination of pellet properties (usually hardness/softness) as well as speeds at which it can stabilize (or not). Diameter can play a role in conjunction will barrel sizing. As well as barrel twist rate or aggression of rifling grooves. In a lot of airguns what we see is that softer pellets tend to almost tear in a button rifled barrel at higher speeds (gettig up toward or past 950fps). In smooth rifling, we see that pellets may be fine at higher speeds than this, but an agressive choke (as is often found) can lead to fast onset of barrel fouling which will eventually cause accuracy to suffer. Which can somewhat be mitigated by bore polishing, and waxing, projetile lube, or all. The ultimate deciding factor if everythign else is in alignment will be harmonics. Harmonics tend to be very nice with a tune as per your suggestion, however, that does not mean that the projectile will leave on a harmonic node, so a slight adjustment in power may yield even more accuracy. Extending nodes can be accomplished by tensioning a barrel, or by bonding carbon fiber to it (or both), these methods stiffen, and make the gun less tune sensative.

Detracting factors to an aggressive tune (wasted air) can be turbulence on the projectile. As well as amplified harmonics. Moderators with very tight clearanced baffles can also reflect pressure waves onto the projectile and exhibit no signs of clipping, but still have a negative affect on accuracy. I alway make sure my mods are in alignment on all of my guns, and I will alter the thread seat face on the muzzle on each gun if it is not aligning. Usually with a small file, but ideally this does not need to be done at all. The reason I alter the gun is because I KNOW my mods are square, and should seat in aligment, assuming the mount on the gun is square.

Overall, in a lot of scenarios, less is more.

Of course, this all has to be balanced with the chosen pellet/projectile which may or may not like the most efficient setting(s).

Anyway, moderators make the most difference with tunes that are not efficient.

And not sure if worded incorrectly, but mods make the least difference with inefficient tunes.

 

[BackStop]

Pretty much dead on, I would jsut add that whether a projectile "likes" certain settings is pretty complex. This CAN be determined by a combination of pellet properties (usually hardness/softness) as well as speeds at which it can stabilize (or not). Diameter can play a role in conjunction will barrel sizing. As well as barrel twist rate or aggression of rifling grooves. In a lot of airguns what we see is that softer pellets tend to almost tear in a button rifled barrel at higher speeds (gettig up toward or past 950fps). In smooth rifling, we see that pellets may be fine at higher speeds than this, but an agressive choke (as is often found) can lead to fast onset of barrel fouling which will eventually cause accuracy to suffer. Which can somewhat be mitigated by bore polishing, and waxing, projetile lube, or all. The ultimate deciding factor if everythign else is in alignment will be harmonics. Harmonics tend to be very nice with a tune as per your suggestion, however, that does not mean that the projectile will leave on a harmonic node, so a slight adjustment in power may yield even more accuracy. Extending nodes can be accomplished by tensioning a barrel, or by bonding carbon fiber to it (or both), these methods stiffen, and make the gun less tune sensative.

Detracting factors to an aggressive tune (wasted air) can be turbulence on the projectile. As well as amplified harmonics. Moderators with very tight clearanced baffles can also reflect pressure waves onto the projectile and exhibit no signs of clipping, but still have a negative affect on accuracy. I alway make sure my mods are in alignment on all of my guns, and I will alter the thread seat face on the muzzle on each gun if it is not aligning. Usually with a small file, but ideally this does not need to be done at all. The reason I alter the gun is because I KNOW my mods are square, and should seat in aligment, assuming the mount on the gun is square.

Overall, in a lot of scenarios, less is more.



And not sure if worded incorrectly, but mods make the least difference with inefficient tunes.

I saw where I was wrong at least in one place where I said "If power alone is essential, the efficiency is not even considered."

If tuned to the knee, that is the optimum efficiency and essentially optimum power setting for any given airgun AFAIK. Unless you consider 3% less than max power to be a limitation.

Of course, I could be wrong and humbly ask that anyone correct me if I am. (smile)

 

[Long_Gun_Dallas]

Well, I have one such gun. The valve in it is a knock open balanced valve. It uses something like 55 bar in a single shot, but the gun only holds about 45cc of air, lol. There is almost no tuning for efficiency, it just makes what power it makes more or less, and it is obscenely inifficient compared to normal valve designs.

Typically, with a normal valve (I'm thinking of my fx crown) and the valve is a semi-balanced valve, so it isn't entirely normal... but it functions like a normal one.... but if we were to tune to the knee of max efficiency. Which for me is something like... with a given hammer weight and given hammer spring tension, at what point do i see negligible power increase for an increase in operating pressure.....? BUT also, where in that adjustmenge range do I find exceptional output where the report of the gun is noticeably tame...? If you tune, you can HEAR when the gun starts wasting air. But still, you can tune well past efficiency for a bit more power.... Sometimes a good bit more... So the limitation is subjective as to what the individual wants. But I just don't see the point in an inefficient tune in most cases.

Just for example, My crown is tuned to 135 bar. Reason being that it is most responsive here. I get more power at a higher pressure, in fact I can get MUCH more power at a much higher pressure, but for a 380mm barrel, the higher pressures or volumes are exceeding the efficiency limitations that the 380mm barrel alone has. A longer barrel would be more efficient. But for a .22 pellet barrel, this length is pretty ideal. Efficiency can be seen in adjustments as well as HEARD. Not only that, but I have a very large range of adjustment at 135 bar. From 960fps all the way down to 650fps on the hammer and port knobs.

So, I can hear that the gun is happy, I can see that the gun is happy in the figures, as well as seen down range on target.

 

[heavy-impact]

Airgun moderator function is simple. Disrupt disperse, and delay flow of chairge air (baffles and volume accomplish this). Dispersing and delaying pressure release. The better these 2 are accomplished the better the result. Sound dampening material like felt can also be used to absorb some of the sound waves addtionally. As stated, this can also be aided by tuning the gun to utilize a smaller, higher pressure charge. Reason being that charge volume is going to be less, which means it is easier to disperse. Often this actually occurs inside the barrel before the mod even begins to do it's job.

I agree and turbulence can be controlled with baffle spacing. Ideally the projectile would seal two baffles at a time so that the high pressure air could never pass the projectile but that's not completely possible. The best we can do is to get as close as possible to sealing without clipping. The cone baffles with a 1mm wall reduce the internal suppressor volume by 2mm diameter and 1mm length per baffle. If we have plenty of volume we can shorten the sidewall of the baffle to equal the straight portion of the projectile and add more baffles.

 

[Long_Gun_Dallas]

Hmmm so you are putting baffles very close together? I actually inadvertently stumbled across this with a factory snow peak mod a couple years back. But it never registered why it was effective until just now. I was trying to get it quieter and had inverted one of the baffles, so one was facing the wrong way, like a funnel and the outlet was very close to the next cone baffle. Substantially quieter than the normal factory config.

 

[Nattboy]

Hmmm so you are putting baffles very close together? I actually inadvertently stumbled across this with a factory snow peak mod a couple years back. But it never registered why it was effective until just now. I was trying to get it quieter and had inverted one of the baffles, so one was facing the wrong way, like a funnel and the outlet was very close to the next cone baffle. Substantially quieter than the normal factory config.

I have one those on my Diana Chaser co2 rifle in .22 caliber. I am impressed with how well it works. PLEASE SEE BELOW

 

[Nattboy]

I purchased a Stoegrer XM1 Bull Shark ( bull pup) in .22 caliber a couple months ago. The rifle is a Snowpeak P 35 in a different stock with some additions. The rifle has a regulator which I believe is set at 140. It has a 265 cc air pressure tube which can be filled to the 250 bar. (2900 psi) The hammer spring can be adjusted from out side of the rifle. The barrel length is 490 mm. The barrel has a shroud which includes a baffled moderator. I haven't had a chance to shoot to the rifle because of health issues and what-nots. Very soon, I hope to test the rifle shooting pellets from 14.5 gr to 19gr. If it's not back yard friendly, I thought I might see if Donny-fl could make an adaptor which would fit the Snowpeak moderator. The rifle has an adaptor but the threads are too large. Also, I was thinking of using one of those foam barrel inserts from Silent Thunder Ordnance. Any thoughts would be appreciated. THANKS Bill