Some background on why I am contemplating this build and going to all this potential trouble vs. just purchasing a traditional commercial 22lr suppressor.

Basically I am looking to build a dedicated 22lr suppressor for my full auto Norrell 10/22 with a ~8" barrel.   I currently have a bunch of traditional industry built 22lr suppressors from DeadAir, AAC, Silencerco, and Gemtech and my long term primary "go to" full auto 22lr suppressor has been an all stainless steel SRT Commanche.

However, all of these suppressors are ~1" in diameter and as a result have some significant drawbacks... the primary of which is a not insignificant amount of back pressure.  This excess back pressure in turn leads to a decent rate of fire increase on the 10/22 and also fouls up the receiver and magazines much quicker leading to a reduced firing schedule before cleaning is needed on the host.   Of secondary concern (or more annoyance) is that these little cans fill up with fouling pretty quick with a full auto firing schedule, so it would be nice to have a design that could go longer in between cleaning.

My primary build goals in order of priority.

- Reduced back pressure
- Ease of cleaning
- Sound reduction (don't really care about FRP in a machinegun)
- Size / Weight
- Cost

In terms of design I am considering making a scaled down MK9K subgun suppressor in 22lr or similar to what Gemtech did with the G5-22.  However, I would make it out of more durable material, better baffle stack, make it easier to clean, and get rid of the needless complexity of a 22lr bilock. (not to mention I don't think the G5-22 has been made in at least 5 years)

In terms of material and construction design:

- 1.5" OD / 1.35 ID / ~5.5" long titanium tubing for the main tube.
- Titanium End Caps to bring the overall length up to ~6".
- Use ~8 to 10 x 60 degree stainless steel shielded/stackable clipped cones that are ~0.8" in diameter and spaced ~0.3" to 0.4" apart.  This should yield a baffle stack ~4" long, leaving me a ~1.5" long / 0.8" OD blast/expansion chamber standoff spacer to bring the full stack length up to 5.5".
- Nest the baffle cones and a ~1.5" long blast chamber spacer inside a 1" stainless steel thin wall tube to keep it all in alignment inside the main tube.  (The 1" baffle stack alignment tube would fit into milled recesses in the end cap and mount cap to keep it centered in the main tube)
- The rear end of the 1" baffle stack alignment tube and the blast chamber standoff spacer will have ~4 to 6 oval ports cut to feed the coaxial volume space surrounding the baffle stack.  (I should have a ~0.17" space all the way around the stack)
- Roll a very thin piece of stainless steel sheet into a cylinder form and which that would slip just inside the main tube to protect the inside wall of the main tube from crud.  (similar to the sparrow clamshell but pressing/flexing outward on the main tube.)

MSPaint Mockup Below:



Black is Titanium Tube/endcaps
Green is rolled stainless steel sheet
Blue is thin wall stainless tube
Purple is the stainless steel baffle stack and expansion/blast chamber standoff spacer


The Gemtech G5-22 seems to have been well received..... albeit not a huge commercial success upon which this F1 design is based so I don't feel like I am wading into completely new design territory here.  

My hope is that a fat tube with a coax design will result in greatly reduced back pressure as the initial uncorking after the bullet leaves the muzzle will effectively vent into a much larger volume area vs. that gas slamming directly into a small diameter baffle stack.  

The projo can then pass through a tried and true ~1" traditional cone baffle stack for hopefully decent suppression.  

Everything is pretty shielded so nothing should get glued together but if things do get locked together it will be made out of materials that are impervious to "the dip".  

It should easily come apart to be cleaned and given the amount of volume it should also hopefully mean this can can go 2 or 3X as long between cleaning compared to a small 1" diameter 22lr suppressor as crud can collect inside the coax area vs. just filling up the first couple baffles.

That said before I go to all this trouble to potentially be disappointed, I am curious if anybody here has built something similar and what the outcome was like.  Maybe I am also overthinking this and I should just ditch the coax design and use fat cones in a fat tube and call it a day or neither a fat coax or fat traditional design will yield much in terms of the back pressure reduction I am seeking.

Open to any thoughts or suggestions based off prior build experience or even just constructive conjecture at this point.

Apples to oranges - I know -  but:

- the quietest can on the market, by a wide margin, is the Hyperion in 30 cal (quietest 30 cal supers can, that is). It’s a co-ax.

There are many different elements and technologies that make up the Hyperion.  But for your design:

- the 1st thing the gas hits in the Hyperion is a dome shaped “baffle” that diverts gas (a lot of it) into the outer co-ax chamber.

You might consider some sort of gas-diverter for your design.

Thanks I will have to look at how the Hyperion is built and the orientation/design of the first baffle.  I was planning to just follow the MK9K design where the Coax ports run up and over the top of the first stamped shallow baffle cone.  That way as the expanding gas hit the cone is is "ramped" up the cone face and jetted off  into the coax ports and space.

Makes you wonder if instead of a single clip on the first cone if it would be better to dual clip  with the clips pointing directly at the coax ports so as the bullet passes through the first baffle and the gas gets jetted laterally by the clips in the face of the cone it pushes that gas right toward the coax ports in the expansion chamber.

Have you looked at the WTT Flo kit? Seems like it would work great for what you want to accomplish. Not sure if you want to spend that much. The facebook form 1 groups are a wealth of knowledge.

The Flo is not a good fit for rimfire, at least not without heavy modification to the flanges.  Even at that, the baffle spacing is not appropriate.

A coaxial rimfire can needs to basically have a "normal" .22 can inside a larger tube.  I've done quite a few coaxial recores of oversized rimfire & pistol caliber cans that didn't perform.  I usually set them up so the diffuser can be located fore or aft, proximal end for reduced backpressure & port pop, distal end for max quiet on manual action. guns.  

I have not looked at the flow kit, thanks for the suggestion.   Cost is pretty low on the attribute list so its not out of the question. Unfortunately I don't do Facebook.

Looking at the design, my concern is that you wouldn't get a whole lot of flow through all those little hole in any meaningful timeframe before the blowback action on a 10/22 opens up.   I would also think I would probably clog the holes in the first and second baffle pretty quick with vaporized lead, carbon, and bullet lube, so any initial flow action would be of quickly diminishing returns.

My current SRT Commanche has a similar sort of flow through design.  Basically its a modified Omega baffle design where the baffles edges don't actually touch the tube wall of the tube so gas can jet out the port holes on the omega baffle collar in front of the cone and then flow around the baffle cone edges into the next Omega baffles void. The problem is that port holes in the first couple of Omega baffle collar completely clog up really quick.

My hope with the coaxial design is there are giant port holes (relatively anyway) so it will take a long time to clog them and a large amount of gas can almost immediately dump unimpeded into a big void before the action opens up.

Have you built a can using one of those WTT Flow kits?  Curious how it performs.

That looks very similar to what I am proposing to build, basically a tube within a tube design.

In the picture it looks like you have it laid out with the coaxial port diffuser on the distal/far end.   How well does it work for back pressure reduction when set up in reverse with the coaxial diffuser on the proximal end?

I never contemplated that I could switch it around like that, but it would be totally doable with what I have in mind.

Interesting on port pop, I would have thought have a big void full of O2 would exacerbate port pop.  Albeit not a huge concern of mine but would be a pleasant bonus none the less.

One of my first cans I made was literally a tube within a tube. I used an old TAC-65 and made caps for each end which were bigger and secured a larger tube. I then literally ported the TAC-65 (at the time a dealer could get a TAC-65 for $109). It was not significantly quieter (only a 2-3dB), but it did reduce blowback to almost nothing. Like your plan, it was for use a Norrell F/A, which was pushing 1500+ RPM with I wanted to slow down.

Thanks, it sounds like I am on the right track here based on the feedback so far.

I put a ton of time slowing my Norrell down from 1200+ RPM unsuppressed to the mid 900s and now have it in the mid 800s with some additional work.  It sucks to put a can on it and have it speed back up 200+ rpm negating a lot of that effort, foul the hell out of the receiver and mags in the process, and having to clean the suppressor every couple range trips so it doesn't permanently weld itself together.  At this  point I rarely shoot it suppressed.  I figured if I could make a custom can to resolve this issue than I can have the best of both worlds, slow ROF with much reduced fouling in the process and it be pellet gun quiet.

I will probably submit an EForm 1 this weekend and will take some pics as I build it in case it turns out nice and somebody else wants to build one.

I'm looking for the same thing.  1.5/1.625 od co-ax design and maybe 4" - 5" long with a Griffin fixed cam-lok interface (once they're available).  Just because the fatties look better on my CP33 & CMR30 SBRs...










Problem is nobody sells anything like this & I don't have the tools to make it myself.  Was thinking about Form1'ing a tube and send in to ECCO for re-core, but not sure how "complete" a Form1 suppressor has to be to send in for this.  My Sparrow SS that I actually use on these guns (though it works well) is too skinny, especially on the CMR.

I got my approved eForm 1 and solvent trap parts about a week ago and will probably start the build process over the next month.

Once its done I will post the results and the build process.