To Subscriber - Gamo Urban moderator insert similar to the Notos insert

[subscriber]

Ntrn,

You may take any info or designs that are published and use them as you see fit; providing what you are doing is legal.

K-baffles with clips generate a lot of useful cross turbulence to slow down gas exit from the front end.  However, unless you have at least one conventional air stripper near the barrel muzzle of an airgun to shield the pellet, such cross turbulence may tend to open groups.  There is nothing to prevent you from combining different baffle styles in one moderator.

Airgun moderators do not just manage air flow; they act as sound filters, and/or absorbers.   Cone baffles are good as air strippers, and manage air expansion and flow, and block sound, rather than absorb it.    Impulse Air moderators use densely nested baffles with an acute cone angle.  That works, but if you print that from plastic, the baffle walls use up too much expansion volume  (you can't realistically print robust 0.5 mm thick baffle walls, while you could machine them from aluminum).  So, to get the benefit of "pointy" cones in a printed moderator, I start with more obtuse cones, where each successive cone angle becomes more acute, and spaced further apart.  I could go into more detail why this works, but suffice to say this style of baffle arrangement is quite effective - based on many designs I have published.

There are many baffle styles that work, so there is not one best way.  A lot depends on how you make the parts, and the cost goals.  Weihrauch moderators use a few flat baffle and wrapped "hair curlers" to good effect.  They work by absorbing sound energy by means of the fiber wrap, and by making the chambers resonate at different frequencies; thus acting as filters to each other.  However, these moderators do not have effective air strippers in them, so they do not help grouping when attached to potent PCP; unless the PCP has an active shroud with its own air stripper.

Spring piston airguns don't have that much air to manage; but the mechanism can make a lot of noise.  So, you may find that a moderator on a springer is not as effective as it could be on a PCP.  I would encourage you to try out your ideas and see what happens.  Just not to assume that a given moderator is useless, if shooting the Silent Cat is still loud.  At least the ones with gas springs do not have steel spring buzz.

PLA is not a very stable plastic; especially at slightly elevated temperatures, such as inside a vehicle, parked in the sun.  So, I would not go too tight on baffle bores with PLA.  I generally do not go very tight anyway because what you gain in noise reduction is moot, if pellets make contact with the baffle bores.  I use 1 mm radial clearance, and then add additional clearance towards the front of the moderator, to the extent of 0.1 mm radial per 25 mm distance.  If I have high confidence in the alignment of the rest of the system, including barrel OD to ID I may go tighter.  If I have less confidence, I may add additional clearance.

[avator]

Credit where credit is due..
Gavin printed and sent me one of Ron's designs for the NOTOS. This one replaces the factory insert and extends the shroud by a few inches. It does work exceptionally well. I really have no need for quite guns where we live but it's pretty cool that the impact of pellet on target is way greater than the report of the gun.
And the fit looks like it came with the gun from the factory. I'm really not a fan of soup can looking objects hanging on the ends of my guns. I much prefer a clean shrouded gun. I think if I was even going to change the Urban it would be a full shroud and the purpose would be purely cosmetic.

[subscriber]

Who is Ron, Bill?

I agree with you that a large pickle on the end of a skinny barrel is not the best look.  A bull barrel look is much nicer.  That does not stop me from designing pickles for those that want them, or their performance.

[avator]

Who is Ron, Bill?

I agree with you that a large pickle on the end of a skinny barrel is not the best look.  A bull barrel look is much nicer.  That does not stop me from designing pickles for those that want them, or their performance.

LOL... my bad, for some reason I thought your real name was Ron.

[subscriber]

for some reason I thought your real name was Ron.

It seems like my camo is working

[urbanGunner]

Many thanks to naptemp and Subscriber for doing it right and making a great moderator replacement for the Gamo Urban .22. I printed the short version and it works perfectly. Exactly what I needed to fix my gun.

[subscriber]

Thanks for the feedback, Mark

[elguapo99]

I printed the short version using PETG on my new Qidi Q1 Pro and it printed perfectly. I didn't need the o-rings since the fit was perfect with no movement whatsoever. I did have to use a round needle file to get the roll pins to line up. The grooves just needed to be a little bit deeper. The sound reduction is way better than that of the OEM baffles and pretty much all I hear now is the sound of the action and the pellet hitting the target. Many thanks to Subscriber and naptemp for developing this. I've also printed a couple of Subsciber's other moderators and they work equally as well.

[subscriber]

We aim to please.