Subscriber designed 3D printed offset reflex moderator

[mackeral5]

Several months back Subscriber and I were engaged in several moderator design discussions and eventually the topic of my little .357 blaster came up.  it is a gun I really enjoy shooting, but could not shoot frequently due to being so loud. 

81gr pellets running 750-800fps out of a 12" barrel is loud, and with a very fast opening/closing valve the muzzle blast is an extremely sharp "CRACK". 

The problem with this gun is there isn't much space between the barrel and tank for a large moderator.  All I had was a 1.25" OD moderator that was originally for a .22, which I bored to .357.  While it helped, the gun was still LOUD.  Previously Subscriber had mentioned offset moderators and in this instance, the timing was right, I was in the mood to try something new so why not.  Let's try one out. 

A lot of back and forth with Subscriber and another board member (who graciously contributed the printing expertise/capability) took place over the course of several weeks.  Lots of test printing, etc.  This gun presented an additional challenge of having a slip-on (glued on) 1/2-20 adapter that created a bulge at the end of the muzzle, which was significantly larger in OD than the barrel itself.  This meant the reflex portion would have to slip over the bulge, but then have a way of being secured to the smaller diameter of the barrel. 

This gun was designed to be modular and has many different possible configurations.  Here is a pic from early in its life, one of many configurations.  This one shows the limited space for a moderator. 



This pic shows the 1/2-20 muzzle adapter and its OD being greater than that of the barrel. 



Later I added a breech riser which helped a bit, and allowed me to run larger OD tanks. 

Here is the gun as it sits today.  12" barrel with Subscriber's offset reflex moderator.  As configured, it is tuned for 20-25 shots of 81gr pellets with a 750-800-750fps bell curve.  Regulating it will yield a tighter string, but for such a short range gun I found regulation to be an unnecessary level of complexity, while it also limited the gun's energy potential.  Unregulated I can lean on the hammer spring and get a much shorter string, but above 800fps.   With the 16" barrel it maxes out just under 200fpe.  While I do not often use the gun this way, it is neat to dial it up every once in a while.

 

Believe it or not the moderator is not affecting the scope's field of view.  When on low power, you barely see a slight blur at the bottom.  I can shoot this as often as a I want with no worries of disturbing neighbors.  Earlier today I was smacking my 70 yard gong and squirrels were cluelessly running around the area, largely unaffected by my discharging 100fpe in their direction.

A few more pics.

Rear showing threaded hole to allow the muzzle bulge to pass through.



The split nut with tapered threads designed by Subscriber and the member contributing 3d print services/expertise.   This is a very trick piece, printed from a flexible print material.  A very slick solution to the problem created by the bulge at the end of the barrel. 

 

And the muzzle end.



I was very skeptical of a 3d printed moderator on my .357 blaster.  After a few hundred rounds of early testing, regulated at 1800psi and tuned in the 100fpe range I became confident in the design.  That is when I reconfigured the gun as unregulated, which when using the 16" barrel and leaning on the hammer spring can produce just under 200fpe.  To date the 3d printed guts epoxied inside an aluminum tube have shown no signs of movement.

All in all this was a very satisfying experience.  3 GTA members who had never met nor heard each other's voices, living across the US, collaborated to design  and manufacture a one-off solution for a very specific application.  The design proved to yield a very effective end product that was very easy to assemble.  a piece of 2" aluminum tubing and epoxy is all that was required after having the 3d printed pieces made.  I made a few mistakes in the assembly process, but thanks largely to Subscriber's design efforts the design was very tolerant of and I was able to recover from those mistakes.   



Hopefully my fellow collaborators will see this and chime in with additional details around their areas of expertise.

[tennx]

⭐️⭐️⭐️⭐️⭐️…..I gave it 5 stars Incase they don’t show up here….u and your collaborators got mad skilz….kudos and good luck

[naptemp]

Can you share the STL files?

[3crows]

That is a cool rifle and an interesting muzzle device for sure!

I am more interested in what barrel that is and how does it attach to the breach/receiver??

Nice work .

[subscriber]

Can you share the STL files?

John, I am not sure what the STLs for a completely custom design would do for you?  If you just want to see what is inside, perhaps the section images below would help?

The hollow box sections front and rear are assembly alignment features, that are removed after the epoxy between tube ID and inserts, and between the front and middle inserts has set.

The concept features a "can in a can" design, with a large eccentric wrap-around forward blast chamber, ahead of the large reflex blast chamber.

[subscriber]

⭐️⭐️⭐️⭐️⭐️…..I gave it 5 stars Incase they don’t show up here….u and your collaborators got mad skilz….kudos and good luck

Thanks, Phil

Since I am not the original poster, I also get to rate the thread five stars 

[mackeral5]

It was a fun project, and again, the design was perfect for DIY assembly. 

here's a pic pre-assembly.

[Ronfiveo]

What about getting a patent and marketing them?

Ron

[mackeral5]

What about getting a patent and marketing them?

Ron

That would take the fun out of it.......at least for me.  I have no desire to pollute/corrupt my hobbies with business.   Others are welcome to do as they wish with what is freely shared on the internet. 

[Nvreloader]

Mike
Too add to your info, I went thru the same process several months ago also,
more than likely with the same Outstanding people as they designed and built my LCD,
that had flow channels thru the full length after the artillery style air diverter at the muzzle.

These air channels moved each blast of air down and thru to the 32" 1" dia Alum LCD tube,
and vented out the bottom, I wanted as quite as possible for blasting Hosp/Starlings
at 25 to 50 yds away.

I can tell you now, that it is a 3 bird quite. Before the build, it was 1 bird quite........
This team is outstanding and designs and builds excellent items
and they have another 5+ star.

[bear air]

Great work Mike. I give five stars as well. I appreciate the threads you post and have learned a lot from them. Keep up the good work.

[subscriber]

What about getting a patent and marketing them?

Ron,

You can't get a patent on something already in the public domain.  By publishing on GTA, this design is now in the public domain.

Of course, someone else could try to patent the idea, and see if the patent examiner found this online.  The standard for patent applications was lowered from proving "first to invent", to "first to file".  That makes stealing ideas much easier.  I short-circuit the process by giving away my ideas and designs for free.

I have over two dozen US patents in other areas of tech, so I understand the process, the benefits, the cost; and what happens if someone violates your patent.  In short, it takes money to prosecute IP thieves, and I don't have that as an individual.  If I was serious, I would apply for a provisional patent, then try to sell it to a company such as Air Venturi.  They are not interested in one-offs.  Only what can be mas-produces to multiply profits.

A company such as AirForce might have application for a large moderator on the Talon, but they already do their own design work.  If I could prove that my designs work better than theirs, I might have their attention.  To do that I have to make parts and demonstrate that to them.  Before showing them anything, they need to sign a non-disclosure agreement.  They might not feel like it, because their attitude is that they don't need any help. 

Without an NDA, showing them parts that work better than their own means they would then be free to copy the design.  So not only a chicken and an egg situation; one that involves a lot of work and cost up front, for potentially no pay off.  Or for a potential legal battle to pursue someone, that claims their new design is nothing like the one you showed them.  I am too old for that...

Besides, just because I thought up something in a way that is new to me and you, does not mean someone else has not thought of it already.  Generally, any idea I can come up with, already has been thought of.   Think of the bow and arrow, invented across the world on separate continents, not just before the internet, but before boats could make it across continents.

Even with the book I wrote above, I am not claiming that the design I did for Mike is better than something else; nor that it can't be improved upon.  In fact, this was a brute force "max volume" approach that is begging to be slimmed down to the point where performance starts to suffer. 

Many of the design choices I made, were based on the assumption that Mike's blaster would eventually be shooting over 200 FPE from a short barrel.  So I prioritized  robustness and durability for such an application, over what I though might make it as quiet as possible.  At the same time, I included design aspect that I know work well from previous designs.  I saw this as an opportunity to explore a new approach, prioritizing function; yet without taking stupid risks that could hurt Mike or damage his property.  The "can in a can" approach was not completely new to my bag of tricks.  I had just done a coaxial design for Mike in .30 that uses it, before this offset one in .357.

[jackssmirkingrevenge]

I like the baffle design, one can just picture the air molecules completely confused as to where they're supposed to go and by the time they reach the exit being too exhausted to make a sound

[Ronfiveo]

What about getting a patent and marketing them?

Ron,

You can't get a patent on something already in the public domain.  By publishing on GTA, this design is now in the public domain.

Of course, someone else could try to patent the idea, and see if the patent examiner found this online.  The standard for patent applications was lowered from proving "first to invent", to "first to file".  That makes stealing ideas much easier.  I short-circuit the process by giving away my ideas and designs for free.

I have over two dozen US patents in other areas of tech, so I understand the process, the benefits, the cost; and what happens if someone violates your patent.  In short, it takes money to prosecute IP thieves, and I don't have that as an individual.  If I was serious, I would apply for a provisional patent, then try to sell it to a company such as Air Venturi.  They are not interested in one-offs.  Only what can be mas-produces to multiply profits.

A company such as AirForce might have application for a large moderator on the Talon, but they already do their own design work.  If I could prove that my designs work better than theirs, I might have their attention.  To do that I have to make parts and demonstrate that to them.  Before showing them anything, they need to sign a non-disclosure agreement.  They might not feel like it, because their attitude is that they don't need any help. 

Without an NDA, showing them parts that work better than their own means they would then be free to copy the design.  So not only a chicken and an egg situation; one that involves a lot of work and cost up front, for potentially no pay off.  Or for a potential legal battle to pursue someone, that claims their new design is nothing like the one you showed them.  I am too old for that...

Besides, just because I thought up something in a way that is new to me and you, does not mean someone else has not thought of it already.  Generally, any idea I can come up with, already has been thought of.   Think of the bow and arrow, invented across the world on separate continents, not just before the internet, but before boats could make it across continents.

Even with the book I wrote above, I am not claiming that the design I did for Mike is better than something else; nor that it can't be improved upon.  In fact, this was a brute force "max volume" approach that is begging to be slimmed down to the point where performance starts to suffer. 

Many of the design choices I made, were based on the assumption that Mike's blaster would eventually be shooting over 200 FPE from a short barrel.  So I prioritized  robustness and durability for such an application, over what I though might make it as quiet as possible.  At the same time, I included design aspect that I know work well from previous designs.  I saw this as an opportunity to explore a new approach, prioritizing function; yet without taking stupid risks that could hurt Mike or damage his property.  The "can in a can" approach was not completely new to my bag of tricks.  I had just done a coaxial design for Mike in .30 that uses it, before this offset one in .357.

Thanks for the explanation.

Ron

[subscriber]

Jack,

That is super funny

[Mr.P]

It’s pretty sweet seeing the various designs conceptualized and brought to life here over the last few years. This is another great example.

[mackeral5]

That is a cool rifle and an interesting muzzle device for sure!

I am more interested in what barrel that is and how does it attach to the breach/receiver??

Nice work .

Sorry, missed this post.  Thanks for the kind words.    it actually has 3 different length barrels.  8.5", 12", and 16", TJ's 1:26.  They are all sleeved up from the  .500  liner up to 17mm cf.  10/32 qty3 barrel set screws.  Bolt lug is 10/32 as well. 

Not practical for much other than lobbing chunks of lead at my 70- 100 yard gongs.  Makes for a nice "smack" and a good grin.

[3crows]

That is a cool rifle and an interesting muzzle device for sure!

I am more interested in what barrel that is and how does it attach to the breach/receiver??

Nice work .

Sorry, missed this post.  Thanks for the kind words.    it actually has 3 different length barrels.  8.5", 12", and 16", TJ's 1:26.  They are all sleeved up from the  .500  liner up to 17mm cf.  10/32 qty3 barrel set screws.  Bolt lug is 10/32 as well. 

Not practical for much other than lobbing chunks of lead at my 70- 100 yard gongs.  Makes for a nice "smack" and a good grin.

Thank you .

[TorqueMaster]

⭐️⭐️⭐️⭐️⭐️…..I gave it 5 stars Incase they don’t show up here….u and your collaborators got mad skilz….kudos and good luck

I figured I should pop in here and take credit as the 3rd Musketeer, as it were.  I did the printing and verified critical dimensions of printed parts.  As well as some material testing  -- verifying the PETG used was of good quality, and the print speed/temperature was getting good layer fusion. 

Truly, subscriber did most of the heavy lifting by creating and cadding the design, I'm just the print monkey, lol.  But I'm proud to have helped build a moderator capable of handling and muting an airgun at these power levels.

[naptemp]

Can you share the STL files?

John, I am not sure what the STLs for a completely custom design would do for you?  If you just want to see what is inside, perhaps the section images below would help?

The hollow box sections front and rear are assembly alignment features, that are removed after the epoxy between tube ID and inserts, and between the front and middle inserts has set.

The concept features a "can in a can" design, with a large eccentric wrap-around forward blast chamber, ahead of the large reflex blast chamber.

It looks different from everything I have seen so far.

What was the air gun it was intended for?