.177 vs .22 noise level…

[subscriber]

my notos shooting 18gr at 850fps is about as quiet as a bone stock buckrail moderated 1322. i wanna know if a .177 akela can shoot 13gr at 900 and if i make a moderator for it can be just as quiet or quieter than my notos.

The .177 is working harder to achieve that speed, but I am sure you can configure a mod to be as quiet as the Notos. If the Akela is running at full power, making it quiet will be more difficult, than if you have it dialed back to 80 or 90 percent of max energy.

Attaching a 1/2-20 mod will require an adaptor such as this:

Benjamin Akela/Kratos 1/2 x 20 Adapter A8

*Note: For the Akela, remove one of the factory baffles in order for the adapter to fit flush. Features: Made by CNC for accuracy Material is 6061 T6 Aluminum Matte black anodize Diamond pattern knurling for easy grip Compatible with .177, .22 and .25 calibers

donnyfl.com

 

[JDGriz]

Sound without a suppressor depends more on (total) FPE and less on the actual caliber per se. With a suppressor - smaller calibers can have more efficient suppressors, but it only really makes a difference in the jump between 10-ish mm to 5-ish mm, all other things (FPE) being equal.

 

[Sawney Bean]

Sound without a suppressor depends more on (total) FPE and less on the actual caliber per se. With a suppressor - smaller calibers can have more efficient suppressors, but it only really makes a difference in the jump between 10-ish mm to 5-ish mm, all other things (FPE) being equal.

One thing that is interesting about unsuppressed noise levels is that springers tend to be noticeably quieter even at the same power levels. We're dealing with pretty much the same physics here, a certain volume of air at a certain pressure in order to produce a given muzzle energy, but there's some hidden variable in there that makes spring piston guns do it with less noise.

 

[JDGriz]

One thing that is interesting about unsuppressed noise levels is that springers tend to be noticeably quieter even at the same power levels. We're dealing with pretty much the same physics here, a certain volume of air at a certain pressure in order to produce a given muzzle energy, but there's some hidden variable in there that makes spring piston guns do it with less noise.

Maybe the effective working pressure? It could be that lower pressures are quieter, at the same FPE, but I'm not sure this makes too much of difference to PCPs; I could be wrong.

 

[subscriber]

One thing that is interesting about unsuppressed noise levels is that springers tend to be noticeably quieter even at the same power levels. We're dealing with pretty much the same physics here, a certain volume of air at a certain pressure in order to produce a given muzzle energy, but there's some hidden variable in there that makes spring piston guns do it with less noise.

You are correct that the average pressure for a given caliber and barrel length should be about the same for a springer and a PCP producing the same power. But, the springer's pressure profile is very spikey; as in high at the start and much lower at the muzzle. Muzzle pressure is what drives the sharpness of an airgun's report.

 

[Sawney Bean]

You are correct that the average pressure for a given caliber and barrel length should be about the same for a springer and a PCP producing the same power. But, the springer's pressure profile is very spikey; as in high at the start and much lower at the muzzle. Muzzle pressure is what drives the sharpness of an airgun's report.

I think that heating the air at the moment of compression and then cooling as it expands probably plays a role too.

 

[subscriber]

I think that heating the air at the moment of compression and then cooling as it expands probably plays a role too.

The heat of compression adds to the energy of the pellet with springers, because heat increases pressure of the air. PCP heat of compression is lost at the compressor or hand pump, so much less efficient than a springer. In compensation, PCPs are easier to shoot, because they don't bounce around (especially challenging with springers, because they bounce before the pellet leaves the barrel).

By the time the air in a springer barrel leaves the muzzle it will have cooled substantially, reducing the pressure. The fact that springer pistons bounce before the pellet leaves the muzzle also reduces muzzle pressure.

Break-barrel springers tend to have longer barrels than they need to produce max velocity considering their tiny volume of compressed air. This is for leverage, as the barrel doubles as a cocking handle. Thus, springers can be very quiet.

 

[Sawney Bean]

The heat of compression adds to the energy of the pellet with springers, because heat increases pressure of the air. PCP heat of compression is lost at the compressor or hand pump, so much less efficient than a springer. In compensation, PCPs are easier to shoot, because they don't bounce around (especially challenging with springers, because they bounce before the pellet leaves the barrel).

By the time the air in a springer barrel leaves the muzzle it will have cooled substantially, reducing the pressure. The fact that springer pistons bounce before the pellet leaves the muzzle also reduces muzzle pressure.

Break-barrel springers tend to have longer barrels than they need to produce max velocity considering their tiny volume of compressed air. This is for leverage, as the barrel doubles as a cocking handle. Thus, springers can be very quiet.

The affect of piston bounce wasn’t something that I had even considered, but it makes perfect sense.