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Feedback on .22 Mono-core design

Posted: Sat Jan 14, 2017 12:59 pm
by VitaminC
Hello.
I am new to the forums and this is my first post.
Still waiting for my Form 1 to be approved and I was hoping to get some feedback on the design for my suppressor.
I did a good bit of research on similar designs that have been posted on this site, so hopefully my design isn't that far off the mark.

I purchased the end caps and the tube, and once approved, I will make the baffles.
Baffles will be 1" aluminum bar stock
.28" Bore
Primary expansion chamber
Five .75" chambers
Eight auxiliary chambers (.75") drilled at 45 degrees to the main baffle chamber

This can will be used on a very accurate bolt action .22 so I would like to get the best possible noise reduction and accuracy out of it.
What I would like to know is:
1. Could this design adversely affect accuracy?
2. Will it be effective?
3. Is the design overkill? (Could it be simplified?)

Thanks for any feedback!

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Re: Feedback on .22 Mono-core design

Posted: Sat Jan 14, 2017 1:53 pm
by a_canadian
I think you could safely extend the blast chamber so that the first wall is similar to the succeeding walls. Won't see a lot of erosion in such a design so leaving extra metal there only wastes volume.

Looks like a wipe up front and that's fine for noise reduction, and in the right place, but when used it's going to worsen accuracy. Otherwise the design should afford somewhat decent suppression. Not as much as K baffles but decent.

Actually on second thought, why not add one more bored chamber, eliminate that first wall right at the muzzle, and instead bore out the blast chamber from the muzzle face to about 0.3" deep? You'll have enough volume there for initial expansion without too much so as to get a lot of FRP, while significantly increasing overall volume.

Re: Feedback on .22 Mono-core design

Posted: Sat Jan 14, 2017 3:18 pm
by VitaminC
Sorry that is not a wipe...just a chamber at the muzzle end.

I made some changes per your suggestions. (Bored out muzzle chamber and extended blast chamber)

Is this what you were thinking?

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Re: Feedback on .22 Mono-core design

Posted: Sat Jan 14, 2017 3:53 pm
by a_canadian
Sort of. But then had second thoughts realising that volume could be increased better with something like this:

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You want a small blast chamber to minimise first round pop (FRP), and volume is important for suppression, so the extra bored cavity gives you that. With decent aluminum (7075) and regular cleaning you shouldn't see a lot of wear, so the wall thickness of the initial baffle doesn't really have to be any more than the rest. Also extended the last chamber, since it's not a wipe holder, as the front cap doesn't need to be anywhere near so thick. Boring right through it for a pin spanner might help in dispersion of pressure, having from 2 to 6 small holes adding venting off-bore.

Oh, and you probably shouldn't countersink your exit hole in the end cap, better to contour it like your blast baffle so as to better strip away flow from the bore. Never discount the baffle value of the end cap, it's more than just a lid.

Re: Feedback on .22 Mono-core design

Posted: Sat Jan 14, 2017 5:20 pm
by VitaminC
Thanks for the feedback, I will make some adjustments to the design.
I think I understand most of your points...luckily I have about 3 more months to get this right.

Re: Feedback on .22 Mono-core design

Posted: Sun Jan 15, 2017 3:39 pm
by VitaminC
Ok I made some changes. In order to maximize the number of chambers, I shrunk the chamber bore size down to 5/8ths, added three more chambers, and went to a staggered design with mouse holes. Also I added some vent holes to the end cap.

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Unfortunately one chamber goes unused...maybe I can drill it into the blast chamber?

Re: Feedback on .22 Mono-core design

Posted: Sun Jan 15, 2017 4:58 pm
by cdakers
There has been some pretty extensive testing done over on the form1suppressor forum that indicates a long tunnel in the endcap may cause Point of Impact shift on the bullet. Anything over .080" long was shown to be problematic. A bore hole at least .100" over bullet diameter in the endcap also helped with supression and POI shift.

Not my data, just my interpretation of testing done by others. I will say that my Form 1 can built using data gleaned from the collective knowledge there performs extremely well and is more than hearing safe. With the gas shut off its almost like in the movies - Hollywood quiet.

Your design looks nice. I have a new mini mill on the way and was thinking of something similar for my next .22 caliber build.

Re: Feedback on .22 Mono-core design

Posted: Sun Jan 15, 2017 11:04 pm
by cdrissel
Your second design is asymmetrical - this will also cause a shift in POI.

Are you limited to just drilling the monocore ? If not it seems like there is a lot of extra material that could be removed to increase the volume.

Re: Feedback on .22 Mono-core design

Posted: Mon Jan 16, 2017 12:07 am
by VitaminC
So is it better to have a few large chambers or many small chambers?

Re: Feedback on .22 Mono-core design

Posted: Mon Jan 16, 2017 1:18 am
by a_canadian
There are a few different theories on that. In my opinion something mid-sized but not of absolutely even spacing/size seems to be good for rimfire. Capt. Link. has thoughts on that, good ones. Breaking up standing waves, decompression-recompression sort of thing. But for the most part you want as little metal in there as is practical for a given application, so as much air volume, but arranged such as to efficiently redirect pressure flow.

Re: Feedback on .22 Mono-core design

Posted: Mon Jan 16, 2017 2:20 am
by fishman
Every component of that design seems thicker and beefier than it needs to be. It'll work, but it'll be a brick on the end of your barrel. What machines do you have access to? Why not just use a spacer for the blast chamber instead of machining it into the monocore? The asymmetry of the blast chamber in your second design is just asking for accuracy and point of impact problems if this is intended for an accurate rifle.

Re: Feedback on .22 Mono-core design

Posted: Mon Jan 16, 2017 8:08 am
by VitaminC
fishman wrote:Every component of that design seems thicker and beefier than it needs to be. It'll work, but it'll be a brick on the end of your barrel. What machines do you have access to? Why not just use a spacer for the blast chamber instead of machining it into the monocore? The asymmetry of the blast chamber in your second design is just asking for accuracy and point of impact problems if this is intended for an accurate rifle.
I have access to a lathe, mill, and CNC, but I was hoping to do all of this by hand.
Everything does look overbuilt, the thickest section is about 3mm.
I like the idea of using a spacer for the blast chamber.
I think I will take your feedback and try to decide a version that could be made on the CNC

Re: Feedback on .22 Mono-core design

Posted: Tue Jan 17, 2017 7:45 am
by VitaminC
So on to design number three.

This is my version of a 60 degree M baffle design. I also added a small stainless steel spacer as a blast chamber. Hopefully it will limit FRP (this will be used on a bolt gun and a 22/45) and also collect a majority of the rim-fire crud.

Wall thickness of the baffle-core is 2mm.

What does everyone think?

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Burnt Bronze Cerakote Version
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Re: Feedback on .22 Mono-core design

Posted: Tue Jan 17, 2017 10:36 am
by fishman
Looks much lighter then the last ones. Probably more effective due to volume increase. Symmetry should maintain accuracy and minimize poi shift.

If you don't mind me asking, why are you doing a monocore instead of a baffle stack? I was planning on doing a monocore for my first build but the more I read the more I changed my mind. I ended up doing k baffles. I'm not telling you you shouldn't, they each have pros and cons.

Re: Feedback on .22 Mono-core design

Posted: Tue Jan 17, 2017 11:25 am
by VitaminC
fishman wrote:Looks much lighter then the last ones. Probably more effective sure to volume increase. Symmetry should maintain accuracy and minimize poi shift.

If you don't mind me asking, why are you doing a monocore instead of a baffle stack? I was planning on doing a monocore for my first build but the more I read the more I changed my mind. I ended up doing k baffles. I'm not telling you you shouldn't, they each have pros and cons.
My main reason for going monocore was because I had the aluminum bar stock sitting around.
Baffles just seemed like more work...plus I am no good on the lathe.

Re: Feedback on .22 Mono-core design

Posted: Tue Jan 17, 2017 11:33 am
by fishman
VitaminC wrote:Baffles just seemed like more work...plus I am no good on the lathe.
Fair enough.

Another bit of advice: guys on here report that silencers with variable spacing and chamber sizes will work better with the smaller chambers first and largest last. You have it set up opposite of that; you might want to switch it around. This is purely second hand information.

Re: Feedback on .22 Mono-core design

Posted: Tue Jan 17, 2017 12:08 pm
by fastfire
VitaminC wrote:
fishman wrote:Looks much lighter then the last ones. Probably more effective sure to volume increase. Symmetry should maintain accuracy and minimize poi shift.

If you don't mind me asking, why are you doing a monocore instead of a baffle stack? I was planning on doing a monocore for my first build but the more I read the more I changed my mind. I ended up doing k baffles. I'm not telling you you shouldn't, they each have pros and cons.
My main reason for going monocore was because I had the aluminum bar stock sitting around.
Baffles just seemed like more work...plus I am no good on the lathe.
There is a way to get good at the lathe, Practice.
Take that bar stock chuck it up indicate it and make funnels, it really doesn't take long at all, OH, and it's FUN!

Re: Feedback on .22 Mono-core design

Posted: Tue Jan 17, 2017 12:09 pm
by fastfire
DOUBBLE POST :shock:

Re: Feedback on .22 Mono-core design

Posted: Wed Jan 18, 2017 12:10 am
by VitaminC
More design variations!

M baffler with side chambers.
Does anyone think this is overkill?

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Re: Feedback on .22 Mono-core design

Posted: Wed Jan 18, 2017 1:04 am
by a_canadian
That's rather beautiful. Two things I'd change, but just personal bias, not sure they're necessary. The little continuations of the baffles outside the core space are only stealing volume. Not a lot, but every bit counts. I'd shave all of those away, or perhaps leave just one in the middle, and have half as many vents, staggering them side to side in alternating walls. A smidge more room for expansion and less lower pressure flow back into the core.

The other thing is the end cap. Still too simple at the exit, though I like it being much reduced like that which obviously increases volume and reduced weight. But I'd carve lips on it. A narrow cutter going down into that space and leaving a sharp edge rising up at the bore edge.

And of course you could play with a random sized void in the middle somewhere to break up sound. Just increasing the middle baffle volume by about 50% maybe, and redistributing the remaining 50% among the baffles before and after.

Re: Feedback on .22 Mono-core design

Posted: Wed Jan 18, 2017 7:51 am
by John A.
I like the outer chambers in the last design vitiminC.

If you were to turn the OD down on a lathe between the outer wall baffles like you have shown, and then machine the monocore baffles on a mill, that would be sweet.

Especially if you ported the outer baffles at the face/corner of the M baffle where the most pressure is going to be just like you have it pictured, should work wonderfully.

Only change I think I would make is the expansion chamber and that's because of personal preference. Instead of a flat face baffle, I'd make a cone because they're good at "splitting the gas" away from the bullet, and I'd port it into the outer chamber of the 2nd baffle, but I wouldn't port the 2nd baffle itself to that outer baffle just so the gas from the expansion chamber couldn't interfere with bullet path.

Essentially, like this >=]>

Essentially making the 2nd outer baffle part of the expansion chamber only. If by chance it did have some FRP on short barrels where the powder hasn't had time for full burn, you could always wrap that outer baffle with copper chore boy to take up some of the volume and disrupting gas/pressure at the same time.

But on a 16 inch barrel, or even a 12 inch barrel for that matter, I doubt you'll notice any FRP at all.

Re: Feedback on .22 Mono-core design

Posted: Wed Jan 18, 2017 2:24 pm
by ZunkerCustoms
Im making that same thing :lol: Started looking up bore dimensions for my project and your post came up, first hit on the monocore .22 search engine!

Ive decided to make different monocore sizes for the different guns I have. Ill make 4 different bore sizes, thread them on my guns and leave them, then just change the internals and body.

I have the accessibility to CNC's but i think ill be using a wire EDM to pocket out my internals. If this one works well, Ill make another body and internals for the modular model. The one Im working on now will more than likely be left on my little Marlin Papoose .22.

Designed on Solidworks and G-coded on MX7. What are you using?

Re: Feedback on .22 Mono-core design

Posted: Wed Jan 18, 2017 3:00 pm
by propeine
ZunkerCustoms wrote:Im making that same thing :lol: Started looking up bore dimensions for my project and your post came up, first hit on the monocore .22 search engine!

Ive decided to make different monocore sizes for the different guns I have. Ill make 4 different bore sizes, thread them on my guns and leave them, then just change the internals and body.

I have the accessibility to CNC's but i think ill be using a wire EDM to pocket out my internals. If this one works well, Ill make another body and internals for the modular model. The one Im working on now will more than likely be left on my little Marlin Papoose .22.

Designed on Solidworks and G-coded on MX7. What are you using?
That would be a no no as you've described it unless you're an 02/07 of course.

Re: Feedback on .22 Mono-core design

Posted: Wed Jan 18, 2017 3:16 pm
by fishman
propeine wrote:
ZunkerCustoms wrote:Im making that same thing :lol: Started looking up bore dimensions for my project and your post came up, first hit on the monocore .22 search engine!

Ive decided to make different monocore sizes for the different guns I have. Ill make 4 different bore sizes, thread them on my guns and leave them, then just change the internals and body.

I have the accessibility to CNC's but i think ill be using a wire EDM to pocket out my internals. If this one works well, Ill make another body and internals for the modular model. The one Im working on now will more than likely be left on my little Marlin Papoose .22.

Designed on Solidworks and G-coded on MX7. What are you using?
That would be a no no as you've described it unless you're an 02/07 of course.
or submit several form 1s

Re: Feedback on .22 Mono-core design

Posted: Wed Jan 18, 2017 3:19 pm
by propeine
fishman wrote:
propeine wrote:
ZunkerCustoms wrote:Im making that same thing :lol: Started looking up bore dimensions for my project and your post came up, first hit on the monocore .22 search engine!

Ive decided to make different monocore sizes for the different guns I have. Ill make 4 different bore sizes, thread them on my guns and leave them, then just change the internals and body.

I have the accessibility to CNC's but i think ill be using a wire EDM to pocket out my internals. If this one works well, Ill make another body and internals for the modular model. The one Im working on now will more than likely be left on my little Marlin Papoose .22.

Designed on Solidworks and G-coded on MX7. What are you using?
That would be a no no as you've described it unless you're an 02/07 of course.
or submit several form 1s
I presumed if he was "leaving on guns" and "changing the body" that he intended to only serialize one tube but yes several form 1s would work as well