Extended Notos muffler inserts

[subscriber]

The 12 FPE .22 Notos PCP is quiet from the factory.  For those who want to hear the hammer drop on firing, rather than the muzzle pop, I offer an extended insert, in two flavors: 

With grooves to hold O-rings, to help center the insert in the stock Notos housing; and a version without the O-ring grooves.

See images below to understand the differences.   STL print files are attached directly below.

[subscriber]

As the above Notos custom insert works rather well, I thought I would offer self-contained versions of the design for general consumption.  These may be attached directly as printed, to any platform that has a matching male threaded stud. 

While these bits are intended for 12 fpe, they should be good to 30 FPE.  For .177 and .22 only.

The first version below has a 1/2 - 20 UNF female thread. 
The second has a 13/16 - 28 female thread.  That is the same thread as a stock Marauder shroud; so a male thread adaptor will be required.

The STL files are attached directly below.

[miksatx]

Finished doing the 1/2”x20 inspired. Used my AirMax .22 for test.
No ldc 111.4 dBA
With Donny tanto 99.2
Inspired ldc 96.1

[subscriber]

Wow, Mike; thanks for your swift work

I hope your result encourages more people to try it.

Oh, by the way, what pellet weight and velocity were those sound values captured at?

[subscriber]

I don't want to be an ingrate, Mike, but do you have a 12 FPE .22 platform that you could try this LDC on?   Tested with the same setup as the Airmax.

Thanks again

[miksatx]

Wow, Mike; thanks for your swift work

I hope your result encourages more people to try it.

Oh, by the way, what pellet weight and velocity were those sound values captured at?

Crosman hp 14.3 825fps bout 20fpe.

[subscriber]

Thanks, Mike.  That is 21.6 FPE

[subscriber]

I realized yesterday, that despite the Notos being rated at 13 FPE on the PA site, it shoots at 19 or 20 FPE as set from the factory.  So, the guys that are now able to hear their hammer strike with my extended insert design installed, are actually shooting at 19 to 20 FPE (confirmed).

This means my statement about "intended for 12 FPE" is incorrect, because clearly it works at almost double that...

[bruce.net]

Thanks for all your work on these. Notos came in Wednesday, hand pump Thursday, printed Friday. I only had PLA which held up great for the 30 shots or so I tested it. Between the print and turning down the hammer spring results in LOUD targets and a quiet Notos.  Reprinting now with some fresh PTEG.

Bambu Lab prints it 4 walls / 100% infill in just over 2.5 hours. 

[subscriber]

Thanks, Bruce

Never heard of Bamboo labs before. 2.5 hours seems very fast.  Link for interested parties:  https://bambulab.com/en/p1

[bruce.net]

The Bambu Lab printers are pretty amazing.  I have been printing stuff for a few years, started with a Wanhoa Duplicator, then an Ender 2.  After "upgrading" to an Ender 3 Pro late last year, and its motherboard failing after a week, I started to research and came across Bambu.  They were just getting started after a Kickstarter campaign for their flagship, and were releasing the P1P around Christmas.  Not cheap at $699, but in line with the Prusa and other higher end consumer printers.

I printed another cone last evening in PETG, but I left it at normal speed.  The printer is so fast that it shakes the entire frame, so taller prints show more quality issues.  I reprinted overnight at 50% speed and it came out perfect.  It took 4.5 hours.

Hopefully I can attach the pictures, black is the PETG, white was the initial PLA print.

Thanks again.

[subscriber]

Nice looking prints; even at "half" speed.  What is the nozzle diameter; and vertical step size you used?

[bruce.net]

.4 nozzle and .20 layer height.

[subscriber]

Thanks, Bruce

[psdavidson812]

Subscriber,

is the short snout basically turning the end into another baffle or is there a reason for a long or short snout?

Thank you sir.

[subscriber]

Patrick,

There is a cavity between the barrel muzzle and the snout inside the stock outer cannister.  The length of the snout affects how far the pellet has to travel before it is in the relatively "wind-still" "shadow" behind the first air stripper.  The longer snout protects the pellet better from initial turbulence, just after it leaves the barrel, but more air will follow the pellet into the second baffle chamber, and that could make the system louder.  So, the longer and shorter snout versions were experiments to see if there was a clear winner for group size and sound reduction. 

In this instance there is no clear winner.  So, either style would work at stock power level or below.  If you could increase the power by 50 or 100% there might be more of a difference in performance.   As this system seems quiet enough, grouping ability would be the metric for making the choice.   If again, the performance for the long and short snout versions are similar, then that suggests a robust system that is rather forgiving.

[psdavidson812]

Patrick,

There is a cavity between the barrel muzzle and the snout inside the stock outer cannister.  The length of the snout affects how far the pellet has to travel before it is in the relatively "wind-still" "shadow" behind the first air stripper.  The longer snout protects the pellet better from initial turbulence, just after it leaves the barrel, but more air will follow the pellet into the second baffle chamber, and that could make the system louder.  So, the longer and shorter snout versions were experiments to see if there was a clear winner for group size and sound reduction. 

In this instance there is no clear winner.  So, either style would work at stock power level or below.  If you could increase the power by 50 or 100% there might be more of a difference in performance.   As this system seems quiet enough, grouping ability would be the metric for making the choice.   If again, the performance for the long and short snout versions are similar, then that suggests a robust system that is rather forgiving.

 Subscriber,
 Thank you for the explanation and all of your hard work.
 I am working on for a HPA airsoft gun and have been look at your design. As impatient as I am, I got my Notos in the mail yesterday and planning on starting the mods this weekend. I have my .2 test print on the printer now and plan on doing a .08 layer later after test fit.

[subscriber]

Patrick,

HPA airsoft is likely to be loud due to supersonic projectile velocities.  No moderator can reduce that supersonic crack sound of the projectile.

Also, the plastic balls might not travel straight down the moderator due to a lack of rifling spin, and large projectile OD to barrel ID clearance.  Unless I misunderstood you, there is a potential for the plastic balls to damage the moderator unless you use generous clearance between baffle bores and projectile.

Perhaps you meant BBs?  Lead or steel BBs should shoot straighter than plastic ones from a smooth bore barrel.  Still, you want to keep the velocity below 1050 FPS, as above 1100 to 1150 FPS they will make a loud whip cracking noise.

[psdavidson812]

Patrick,

HPA airsoft is likely to be loud due to supersonic projectile velocities.  No moderator can reduce that supersonic crack sound of the projectile.

Also, the plastic balls might not travel straight down the moderator due to a lack of rifling spin, and large projectile OD to barrel ID clearance.  Unless I misunderstood you, there is a potential for the plastic balls to damage the moderator unless you use generous clearance between baffle bores and projectile.

Perhaps you meant BBs?  Lead or steel BBs should shoot straighter than plastic ones from a smooth bore barrel.  Still, you want to keep the velocity below 1050 FPS, as above 1100 to 1150 FPS they will make a loud whip cracking noise.

I got one made for the airsoft. the fps is only 320. and only pushes 100psi. It works good, I used acoustic foam and a baffle design like you used. Do you think this would also work for an airgun. Baffles then a foam core?

[subscriber]

Patrick,

The devil is in the details.  I can't comment on a design I have not seen.

Just a head's up, this forum is for airguns shooting pellets, slugs and BBs.  They do not entertain discussions about airsoft guns.  Not unless it is pertinent to airguns shooting pellets, slugs or BBs.