Given my interest in taking on new and interesting projects, a friend of mine recently asked me to design a suppressor for his .300blk rifle (he's looked for commercially available cans, but has found none which fit his constraints so we're going to go the F1 route). That being said, this is the first suppressor I've ever designed so I'd very much appreciate any critiques and feedback you all have.
Design constraints:
- the host will be an 8" bbl 300 BLK AR-15
- the hosts fore-rail is 10" in length, so the suppressor must fit ~2" inside the rail
- the rail is about 1.3" ID, so the can OD must be no larger than ~1.25"
- the host firearm will shoot primarily sub-sonic ammo, though super-sonic WILL be run through the can on occasion
- the host firearm will be SEMI-ONLY
General specs:
- outer tube: .063" wall
- baffle spacers: .058" wall
- bore dia.: .375"
- OD: 1.25"
- OAL: 10.5"
- Weight: 21.1oz (estimated)
Other details:
- baffle spacer "mouse holes" are .250" dia
- blast baffle is ~1" from muzzle crown
Initially designed to have threaded end-caps, I'm now leaning toward a welded tube given the occasional super-sonic use.
Parts in TAN are spec'd 304 SS, whereas parts in GRAY are spec'd 6061 AL (we're not opposed to switching to 7075 if there's value in doing so, however).
I've (sort of) considered doing the outer tube and caps in TI, but I don't personally have any experience working with it (welding or machining) and I don't really feel like a pressure vessel is the best place to "cut my teeth" with learning a new material (more the welding than the machining, but my point stands).
I'm also wondering if we can get away with eliminating a baffle or two and shortening it down but still maintain hearing-safe with sub-sonic and "almost-safe" with super-sonic.
My first (ever) suppressor design - .300blk
- Bendersquint
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Re: My first (ever) suppressor design - .300blk
Might want to check with Joe Gaddini before you start making that.
Re: My first (ever) suppressor design - .300blk
why did he do one that was just like that?Bendersquint wrote:Might want to check with Joe Gaddini before you start making that.
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Re: My first (ever) suppressor design - .300blk
He owns the patent.dagamore wrote:why did he do one that was just like that?Bendersquint wrote:Might want to check with Joe Gaddini before you start making that.
Re: My first (ever) suppressor design - .300blk
I was not aware that there is a patent on stepped cone baffles, and given that there are dozens of threads about cans on here with them that weren't derailed about patent discussions, it would be nice if you could please not continue to do that to my thread.Bendersquint wrote:He owns the patent.dagamore wrote:why did he do one that was just like that?Bendersquint wrote:Might want to check with Joe Gaddini before you start making that.
As the final nail, if its ultimately necessary to get permission to use stepped cone baffles, I'll happily "track down" and call Joe Gaddini to explain that I'd like to use stepped cone baffles in a form 1 can (like everyone else already does, but without permission).
In an effort to get this back on a useful track I submit the following questions:
- are the baffles too close together for the stated design goal? Should some be removed and the spacers elongated?
- can the can be shorter (with fewer baffles) and still meet the stated goals?
- is stainless absolutely necessary for the tube and endcaps or can aluminum be used?
- aside from under-cutting the baffles to have the step shape on the back side, are there any tricks I'm missing that could be done to save weight (assuming the tube and caps can't be made of AL, and we opt not to try our hand at TI)?
- I'm not sure what impact (if any) would be had on putting holes in the blast spacers. Would that simply increase volume and reduce weight without losing durability, or would the potential for gas-erosion of the main tube make that not a good idea? If the tube were instead aluminum, I realize this would absolutely be a no-no. What about if it's TI?
- are the "mouse holes" in the baffle spacers an appropriate size or should they be larger/smaller?
- having read that "clipping" the baffles causes accuracy issues, how much of an impact might clips 120* apart have? from further reading after posting, it seems that the clips make a pretty significant difference in noise reduction so I'm wondering if at least a portion of the middle baffles should be clipped in such a "symmetrical" fashion.
- running load data through quick load, muzzle pressures on super-sonic 300blk are predicted in the 10kpsi range (8" barrel). in the world of suppressor baffles, would that be considered a "high pressure" or "low pressure" environment? 9mm seems to be between 5-6k and I know this is regarded as "low pressure" ("K" baffle), but .308 win comes out at 7100psi muzzle (24" barrel) and this seems to be classified as a "high pressure" baffle ("M", cone, stepped cone) cartridge in discussions.
Re: My first (ever) suppressor design - .300blk
looking at your drawing, taking one spacer and one baffle together look like a single "Omega" baffle. That is what the patent is for, not stepped cones.
viewtopic.php?f=10&t=121887
Where did you get the idea/drawing?
viewtopic.php?f=10&t=121887
Where did you get the idea/drawing?
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Re: My first (ever) suppressor design - .300blk
The step cone is not the patent issue, the coaxial chambers(what you are calling baffle spacers) is the patent issue.sillycon wrote: I was not aware that there is a patent on stepped cone baffles, and given that there are dozens of threads about cans on here with them that weren't derailed about patent discussions, it would be nice if you could please not continue to do that to my thread.
As the final nail, if its ultimately necessary to get permission to use stepped cone baffles, I'll happily "track down" and call Joe Gaddini to explain that I'd like to use stepped cone baffles in a form 1 can (like everyone else already does, but without permission).
In an effort to get this back on a useful track I submit the following questions:
- are the baffles too close together for the stated design goal? Should some be removed and the spacers elongated?
- can the can be shorter (with fewer baffles) and still meet the stated goals?
- is stainless absolutely necessary for the tube and endcaps or can aluminum be used?
- aside from under-cutting the baffles to have the step shape on the back side, are there any tricks I'm missing that could be done to save weight (assuming the tube and caps can't be made of AL, and we opt not to try our hand at TI)?
- I'm not sure what impact (if any) would be had on putting holes in the blast spacers. Would that simply increase volume and reduce weight without losing durability, or would the potential for gas-erosion of the main tube make that not a good idea? If the tube were instead aluminum, I realize this would absolutely be a no-no. What about if it's TI?
- are the "mouse holes" in the baffle spacers an appropriate size or should they be larger/smaller?
- having read that "clipping" the baffles causes accuracy issues, how much of an impact might clips 120* apart have? from further reading after posting, it seems that the clips make a pretty significant difference in noise reduction so I'm wondering if at least a portion of the middle baffles should be clipped in such a "symmetrical" fashion.
- running load data through quick load, muzzle pressures on super-sonic 300blk are predicted in the 10kpsi range (8" barrel). in the world of suppressor baffles, would that be considered a "high pressure" or "low pressure" environment? 9mm seems to be between 5-6k and I know this is regarded as "low pressure" ("K" baffle), but .308 win comes out at 7100psi muzzle (24" barrel) and this seems to be classified as a "high pressure" baffle ("M", cone, stepped cone) cartridge in discussions.
That said....
- You can probably remove a couple baffles and meet your goals.
- For anything supersonic rated you should use either SS or Ti for the tubing, remember that part can't be replaced so make sure it lasts.
- I have seen guys do aluminum exit caps and a few of them were blown down range. I would personally use SS or Ti for durability and strength.
- Ti is really not that hard to work with(especially with the equipment that you have).
- "Blast spacers" thats the patent issue noted above.
- "Clipping" in any of the various definitions of the term can have accuracy issues if not done correctly, too deep, wrong angle, too large etc.... As far as sound reduction benefit, the Form1 builder will experience more of a notable change than most manufacturers doing it, so try the "clipping" a little at a time until you are happy.
- Yes, supersonic 300BLK is considered a high pressure round.
Re: My first (ever) suppressor design - .300blk
Bendersquint wrote:The step cone is not the patent issue, the coaxial chambers(what you are calling baffle spacers) is the patent issue.sillycon wrote: I was not aware that there is a patent on stepped cone baffles, and given that there are dozens of threads about cans on here with them that weren't derailed about patent discussions, it would be nice if you could please not continue to do that to my thread.
As the final nail, if its ultimately necessary to get permission to use stepped cone baffles, I'll happily "track down" and call Joe Gaddini to explain that I'd like to use stepped cone baffles in a form 1 can (like everyone else already does, but without permission).
In an effort to get this back on a useful track I submit the following questions:
- are the baffles too close together for the stated design goal? Should some be removed and the spacers elongated?
- can the can be shorter (with fewer baffles) and still meet the stated goals?
- is stainless absolutely necessary for the tube and endcaps or can aluminum be used?
- aside from under-cutting the baffles to have the step shape on the back side, are there any tricks I'm missing that could be done to save weight (assuming the tube and caps can't be made of AL, and we opt not to try our hand at TI)?
- I'm not sure what impact (if any) would be had on putting holes in the blast spacers. Would that simply increase volume and reduce weight without losing durability, or would the potential for gas-erosion of the main tube make that not a good idea? If the tube were instead aluminum, I realize this would absolutely be a no-no. What about if it's TI?
- are the "mouse holes" in the baffle spacers an appropriate size or should they be larger/smaller?
- having read that "clipping" the baffles causes accuracy issues, how much of an impact might clips 120* apart have? from further reading after posting, it seems that the clips make a pretty significant difference in noise reduction so I'm wondering if at least a portion of the middle baffles should be clipped in such a "symmetrical" fashion.
- running load data through quick load, muzzle pressures on super-sonic 300blk are predicted in the 10kpsi range (8" barrel). in the world of suppressor baffles, would that be considered a "high pressure" or "low pressure" environment? 9mm seems to be between 5-6k and I know this is regarded as "low pressure" ("K" baffle), but .308 win comes out at 7100psi muzzle (24" barrel) and this seems to be classified as a "high pressure" baffle ("M", cone, stepped cone) cartridge in discussions.
That said....
- You can probably remove a couple baffles and meet your goals.
- For anything supersonic rated you should use either SS or Ti for the tubing, remember that part can't be replaced so make sure it lasts.
- I have seen guys do aluminum exit caps and a few of them were blown down range. I would personally use SS or Ti for durability and strength.
- Ti is really not that hard to work with(especially with the equipment that you have).
- "Blast spacers" thats the patent issue noted above.
- "Clipping" in any of the various definitions of the term can have accuracy issues if not done correctly, too deep, wrong angle, too large etc.... As far as sound reduction benefit, the Form1 builder will experience more of a notable change than most manufacturers doing it, so try the "clipping" a little at a time until you are happy.
- Yes, supersonic 300BLK is considered a high pressure round.
What He is saying is pretty much correct, the specific patent looks to be US6575074 B1 which includes the spacers that are VERY similar to you own.
Here is the actual patent in question -https://www.google.com/patents/US657507 ... WICh2cDAuK
Honestly, i like your design, but i have practically zero knowledge, and actually just joined this site to try and wrap my head around designing a firearm silencer for a form one construction.
Re: My first (ever) suppressor design - .300blk
Thank you everyone for your design feedback. It is very appreciated!
So far as the idea, the design process went as such:
Having read of lots of pleased folks with the Octane 45 on the .300blk with sub-sonics, I figured I'd start off with finding out the max possible internal volume of an Octane 45 (10.26ci). Needing to be at 1.25" OD max, I calculated the length of tube I'd need to get to a similar volume - 10.5" gets me 10.34ci. Both measurements assume .065" wall thickness.
After reading up on rifle can designs, it seemed cones/M baffles were preferred. Speaking of which -- I haven't been able to figure out from reading what the functional difference is between the two, if any. It seems like the main difference is which side of the "baffle" the "spacer" is attached to. Is that really the difference, or is there something more subtle that I'm missing?
Anyhow, not wanting to spend unnecessary hours at my manual lathes (as lathe use tends to increase my chiropractor bills...) I didn't want to make the baffles out of billet so I "broke them apart" into separate baffle "flats" and tubular "spacers" (this also lends itself to mixing a SS "flat"/baffle with an aluminum "spacer" for a bit of weight savings). Given the "dicta" of cone/M baffles, I figured that since cones/M's are smooth and turbulence is a good thing in cans, stepped cones/M's must be better. The steps also increase surface area which helps with heat transfer. At that point I wanted to try and maximize surface area and turbulence so I added a slight radius to each of the steps (it also cuts down on weight, although minimally). Thinking about it now, I may also want to add a radius on the outer diameters of each step... Flow separation here I come! (Deliberate attempts at flow separation are also why there is a step going from the 30* angle of the baffle back-side to the baffle spacer).
So far as the spacers, I initially did them as having an OD the same size as the ID of the outer tube, but while adding in the radii to the baffle steps I realized I could get more surface area for heat-sinking by reducing their diameter and exposing the outer tube to the combustion gases directly. Given the patent links posted, this seems to be where I stumbled into "Omega" territory.
It's a simplistic approach, to be sure, but with no prior personal experience to draw from it's what I've got to work with. I'm also not a fan of just directly (and intentionally...) copying someone elses' work (a-la opening up some of my personally owned cans and copying the guts) as that takes the fun out of the journey and I find that you don't learn nearly as much that way.
I'm also going to revise the end caps to be fully inset into the tube. That should reduce the weight another half an ounce or perhaps even a bit more.
As it sits, about 55% of the weight of the can is in the outer tube! Given benders input, I'll look into the possibility of TI tubing as that would be a *MASSIVE* weight savings.
My apologies if these sorts of things have been covered previously on here, but I haven't really stumbled across much discussing these aspects of suppressor design in my searches.
Thanks again to everyone!
The drawing is a model I made in Solidworks.mr fixit wrote:looking at your drawing, taking one spacer and one baffle together look like a single "Omega" baffle. That is what the patent is for, not stepped cones.
viewtopic.php?f=10&t=121887
Where did you get the idea/drawing?
So far as the idea, the design process went as such:
Having read of lots of pleased folks with the Octane 45 on the .300blk with sub-sonics, I figured I'd start off with finding out the max possible internal volume of an Octane 45 (10.26ci). Needing to be at 1.25" OD max, I calculated the length of tube I'd need to get to a similar volume - 10.5" gets me 10.34ci. Both measurements assume .065" wall thickness.
After reading up on rifle can designs, it seemed cones/M baffles were preferred. Speaking of which -- I haven't been able to figure out from reading what the functional difference is between the two, if any. It seems like the main difference is which side of the "baffle" the "spacer" is attached to. Is that really the difference, or is there something more subtle that I'm missing?
Anyhow, not wanting to spend unnecessary hours at my manual lathes (as lathe use tends to increase my chiropractor bills...) I didn't want to make the baffles out of billet so I "broke them apart" into separate baffle "flats" and tubular "spacers" (this also lends itself to mixing a SS "flat"/baffle with an aluminum "spacer" for a bit of weight savings). Given the "dicta" of cone/M baffles, I figured that since cones/M's are smooth and turbulence is a good thing in cans, stepped cones/M's must be better. The steps also increase surface area which helps with heat transfer. At that point I wanted to try and maximize surface area and turbulence so I added a slight radius to each of the steps (it also cuts down on weight, although minimally). Thinking about it now, I may also want to add a radius on the outer diameters of each step... Flow separation here I come! (Deliberate attempts at flow separation are also why there is a step going from the 30* angle of the baffle back-side to the baffle spacer).
So far as the spacers, I initially did them as having an OD the same size as the ID of the outer tube, but while adding in the radii to the baffle steps I realized I could get more surface area for heat-sinking by reducing their diameter and exposing the outer tube to the combustion gases directly. Given the patent links posted, this seems to be where I stumbled into "Omega" territory.
It's a simplistic approach, to be sure, but with no prior personal experience to draw from it's what I've got to work with. I'm also not a fan of just directly (and intentionally...) copying someone elses' work (a-la opening up some of my personally owned cans and copying the guts) as that takes the fun out of the journey and I find that you don't learn nearly as much that way.
I'm also going to revise the end caps to be fully inset into the tube. That should reduce the weight another half an ounce or perhaps even a bit more.
As it sits, about 55% of the weight of the can is in the outer tube! Given benders input, I'll look into the possibility of TI tubing as that would be a *MASSIVE* weight savings.
Ok. We may have to give that a whirl too then (e.g. 2nd F1).Bendersquint wrote:- You can probably remove a couple baffles and meet your goals.
How is super-sonic so different from subsonic? Is it really just the few thousand PSI extra from the muzzle? Or does the sonic wave generated by the bullet become a factor as well?Bendersquint wrote:- For anything supersonic rated you should use either SS or Ti for the tubing, remember that part can't be replaced so make sure it lasts.
As noted, we'll give it more thought. That will probably come down to a materials cost decision. I'd probably still go with SS for the caps, so instead of welding I'd thread the caps in. Are threaded caps an issue in a can/situation like this? I know TI can be welded to SS, but that's just further complication to an already new process - which, again, is not my preference for this particular project.Bendersquint wrote:- Ti is really not that hard to work with(especially with the equipment that you have).
By "blast spacers" I was referring to the two spacers surrounding the "disk" at the muzzle end of the can. As the disk is only 1" from the muzzle, I don't know if that's enough space to be effective. Would it be more useful at 1.5" from the muzzle?Bendersquint wrote:- "Blast spacers" thats the patent issue noted above.
The accuracy issue is exactly why I'd want to try and keep it symmetrical. I'd hope that the accuracy issues would arise from unequal movements of the gas surrounding/behind the bullet so making them symmetrically should limit those sorts of issues.Bendersquint wrote:- "Clipping" in any of the various definitions of the term can have accuracy issues if not done correctly, too deep, wrong angle, too large etc.... As far as sound reduction benefit, the Form1 builder will experience more of a notable change than most manufacturers doing it, so try the "clipping" a little at a time until you are happy.
For my own edification, at what pressure level does a particular cartridge become a "high pressure" round vs. a "low pressure" one? Also, what pressure measurement would one go by? E.g. Muzzle pressure or max chamber pressure?Bendersquint wrote:- Yes, supersonic 300BLK is considered a high pressure round.
My apologies if these sorts of things have been covered previously on here, but I haven't really stumbled across much discussing these aspects of suppressor design in my searches.
Thanks again to everyone!
Re: My first (ever) suppressor design - .300blk
TI tube, inset end caps, and thinned blast baffle. Estimated weight is now 14.9oz.
Given the absurd strength/weight ratio of TI vs SS, the tube could probably be thinned down to .050 from .065 (or more, if one wanted to push it) but a < 1lb DIY "rifle" can is already nothing to sneeze at. The end cap revision brings the can to 10.125" OAL and took off a full ounce as well.
Bender, when removing baffles would you leave the OAL the same and simply increase the spacer length between baffles, or would you also chop down the OAL of the can?
Given the absurd strength/weight ratio of TI vs SS, the tube could probably be thinned down to .050 from .065 (or more, if one wanted to push it) but a < 1lb DIY "rifle" can is already nothing to sneeze at. The end cap revision brings the can to 10.125" OAL and took off a full ounce as well.
Bender, when removing baffles would you leave the OAL the same and simply increase the spacer length between baffles, or would you also chop down the OAL of the can?
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Re: My first (ever) suppressor design - .300blk
Make the can shorter, change your baffle design and give your thread mount something to shoulder on.
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Re: My first (ever) suppressor design - .300blk
Bender you recommended changing the baffle design are you saying to step away from the stepped cones (pun intended) or get away from the coaxial spacers to avoid IP/patent issues?
Those convinced against their will are of the same opinion still.
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Re: My first (ever) suppressor design - .300blk
Yes....both.noisecatcher wrote:Bender you recommended changing the baffle design are you saying to step away from the stepped cones (pun intended) or get away from the coaxial spacers to avoid IP/patent issues?
Primarily recommending to get away from the Omega baffle design,
Other baffle designs are better suited for the type layout he has as well. Step cones won't work the best with his design.
Re: My first (ever) suppressor design - .300blk
What sort of design would you suggest? The latest revision above moved the spacers out to meet the outer tube so there should no longer be an issue with the omega patent.Bendersquint wrote:Yes....both.noisecatcher wrote:Bender you recommended changing the baffle design are you saying to step away from the stepped cones (pun intended) or get away from the coaxial spacers to avoid IP/patent issues?
Primarily recommending to get away from the Omega baffle design,
Other baffle designs are better suited for the type layout he has as well. Step cones won't work the best with his design.
Doing cfd analysis on this design was somewhat disappointing, I must admit. I realize that its not a perfect model given all the things happening inside a can, but the lack of turbulence was surprising.
When I get time maybe I'll try swept cones and see how that does.
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Re: My first (ever) suppressor design - .300blk
Have you thought about turning the distal cap, blast chamber and tube threads into a single, larger design?
You could profile this to the 1.25" and enlarge it, once past the forearm. This will allow you to gain volume with a larger tube size.
I even incorporated an internal thread for a blast baffle to be installed.
I would think 7" of tube, beyond the rail, with 60* cones would be a contender.
Is plug welding the baffles an option? You could save a bunch of weight.
You could profile this to the 1.25" and enlarge it, once past the forearm. This will allow you to gain volume with a larger tube size.
I even incorporated an internal thread for a blast baffle to be installed.
I would think 7" of tube, beyond the rail, with 60* cones would be a contender.
Is plug welding the baffles an option? You could save a bunch of weight.
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Re: My first (ever) suppressor design - .300blk
ATF would consider the part in this sketch a silencer part and because of the design it would count towards the OAL of the silencer.T-Rex wrote:Have you thought about turning the distal cap, blast chamber and tube threads into a single, larger design?
You could profile this to the 1.25" and enlarge it, once past the forearm. This will allow you to gain volume with a larger tube size.
I even incorporated an internal thread for a blast baffle to be installed.
I would think 7" of tube, beyond the rail, with 60* cones would be a contender.
Is plug welding the baffles an option? You could save a bunch of weight.
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Re: My first (ever) suppressor design - .300blk
I see more designs using 60* cones and K's for the 300blk followed by simple freeze plugs. I am far from an expert but I was under the impression that the step cones are best suited for higher pressure rounds like .308 and the .30 caliber magnum loads. I am not saying that they won't effectively quiet the 300blk just saying it isn't a mainstream option. However, I like when people try things out of the norm and status quo so I will be interested to hear how this pans out.T-Rex wrote:Have you thought about turning the distal cap, blast chamber and tube threads into a single, larger design?
You could profile this to the 1.25" and enlarge it, once past the forearm. This will allow you to gain volume with a larger tube size.
I even incorporated an internal thread for a blast baffle to be installed.
I would think 7" of tube, beyond the rail, with 60* cones would be a contender.
Is plug welding the baffles an option? You could save a bunch of weight.
Those convinced against their will are of the same opinion still.