Planning 2 more F1s

[Gunfixr]

Ok, I know, haven't even started my rimfire suppressor yet. But, spent a day last week shooting with that multi-cal suppressor I built on my .308 bolt gun, and words of the friend I was with echoed in my mind: "When you have a suppressor, why would you shoot without one."
So, I need more of them.
The e-file F1 process is faster than doing them on the 07 and F4, and they're for me anyway, so I'm going to just F1 it.
Going to build a suppressor for a 16" barreled AR rifle. It will be a dedicated can for this gun. The barrel is a lightweight profile barrel, so I want it as light as is reasonable. To this end, it will be all stainless, all welded. I am thinking a reflex unit. I have approx. 3 1/4" of barrel in front of the handguard to the muzzle. So, I was thinking of direct thread to the muzzle, covering most of this space to the handguard, and going out maybe 4-5" past the muzzle. I am thinking either 1.75" OD or 2" OD. This should give a good sized blast chamber. Baffle plans are 3, maybe 4 cones. Light yet hearing safe is the desired result. Hollywood quiet is not required. Full powered ammo is the norm, full auto is not going to happen.
Thoughts are 316 ss tube, .065" wall, baffles cut from 316 bar stock, and plug welded in place. inner sleeve barrel tube same wall thickness, with muzzle end made from bar stock and welded in place. Supports would be installed to keep the muzzle centered. Baffles plug welded in place, end cap welded in place. There would be no spacers.
So, my question is, is .065" wall sufficient, can I go down to .049"? Is 1.75"OD good, or is 2"OD better? Online metals only lists .065" in 1.75", but lists .065" and .049" in 2".


ETA: Thinking on this, I'm going to drop the 10.5" gun for now. I hardly ever shoot the thing, it's a pistol, and I'm even thinking on SBR'ing it, or maybe making it a .300BO, as it's not all that accurate as is.

On both, seamless tube is to be used, on both, 316ss. In fact, all of it is to be 316ss. I enjoyed doing the multi-cal in titanium, and have a very nice tig machine, but proper welding of titanium requires procedures I don't have the equipment for. Plus, I can build both these in ss for way less than one of them in titanium.

ETA: Now looking at the pic, that unit looks like it might be about 2" OD.

The plan is something like this:

[Gunfixr]

Wow, 125 views, and not one opinion.

Or, at least not one opinion anybody is willing to share.

Not asking anybody to design my suppressor, just thoughts on tube thickness for my application.

[whiterussian1974]

So, my question is, is .065" wall sufficient, can I go down to .049"? Is 1.75"OD good, or is 2"OD better? Online metals only lists .065" in 1.75", but lists .065" and .049" in 2".

I'm responsible for 4-6 of those views. There was alot of info and I didn't see the above ?s in all that text.

Yes, .049" wall thickness is fine. B/c you have so much reflex volume, the gas will drop pressure to safe levels. Also, if you want you can add a thin ring of metal where the blast baffle contacts the tube. That's the structurally weakest point of such a design.

And yes, 2" OD is better than 1.75" if it doesn't obstruct your sightline.

I further commend you on choosing a reflex design for use on ARs. The high ejection port noise is only made worse by cans that create extra backpressure.

In fact, I doubt that an AR can be hearing safe w/o modifying the timing of the bolt cycle. There are many threads explaining what mods are needed to quiet ejection port noise. And semis usually aren't hollywood quiet. Some subsonic .22 and .300BLK. But not .223 and .308.

[c5_nc]

The thicknesses you listed should be good. Titantium Tubing would save a lot of weight. There is not a lot of testing or form 1 builds for reflex cans, only Allen and Griffin are producing them commercially, Griffin's 8.8" and Allen's 8.5" and 8.9" (Allen has 3 more models but are loud) extend back over the barrel 2" or so behind the brake, and this is with 1.5" OD tube so this not much area.

Here was my proposed build, I have the stamp back but have not proceeded yet. I imagine this would replicate the Allen and Griffin commercial cans.

viewtopic.php?f=10&t=132694

This was another thread recently that had more discussions of larger reflex cans:

viewtopic.php?f=10&t=132687

[Capt. Link.]

The e-file F1 process is faster than doing them on the 07 and F4, and they're for me anyway, so I'm going to just F1 it.

While e-file will reduce the time to put a stamp in your hand why do it.If I get a wild hair up my butt and wish to build a can or cut a barrel short I just do it.I can always do a form latter to add it to my personel collection.I see no logic in doing a form 1 when you have a 02/07.

[Gunfixr]

Ok, sorry about that.
The question was about the wall thickness. I searched as best I could, the search function here doesn't seem to work very well, at least for me.
But, I see where a lot of people will simply ask if they can build a "5.56 can with a wall thickness of xxx?", and that's it, no more details. So, I was trying to give more details. My searches sometimes mentioned spacers, and sometimes didn't, so I wanted to be clear I was not planning on spacers. I guess I just crammed so much in the post, the question got buried.

I could build this out of titanium, but two things come to mind. One, really the most important one, is welding it. I researched welding titanium before building my multi-cal can, and while the process is straightforward, it involves some more specialized details. Such as a gas chamber, to keep air away. Just on a whim, I tried fusing some of the leftover titanium from that build, and it's acting very brittle. This is not what I want when welding in baffles and end caps. I do have a very good TIG machine, and have the proper filler for 316ss. I'd have to buy a minimum of 1lb of titanium filler, at over $200. Second, I was looking to build this one more "on the cheap". Not freeze plug cheap, but less than titanium. That's why I was hoping to be able to run .049" wall, to save some weight. Putting my 19oz suppressor on the end of the rifle I am building this unit for drops POI almost a full MIL. I need to weigh it with the adapter, it adds a lot. It should be less anyway, as the reflex unit will be set back, and will cantilever differently, but I am hoping to get it in under 15-16oz.
Now, if there is a way to solidly weld stainless to titanium, I'm all ears.

Yes, with the 07, I can just build it, and transfer it later. However, I don't own the business, I work there. It's not a sole proprietership, it's an LLC. So, while I can take stuff the shop owns/possesses out as an employee, it means a lot of papers to carry around. Since it's going to be welded up, I can't change it around anyway. We are not any kind of a production shop. The only reason we got an 07 was because atf decided a type of gunsmithing work we were doing a lot of several years ago was classified as "manufacturing". We got the 07, and added the sot, because, why not? That work has come almost to a stop now, and with the recent sanctions against Russia, is unlikely to change. The owner almost didn't renew it this year. The vast majority of what I do is everyday gunsmithing. The multi-cal suppressor I made wasn't even actually started until after the F4 had come back a month. I sent in the F2, it came back and I sent in the F4, waited over 9 months and it came back, and it was over a month before I got it actually started, because I was busy making a paycheck.
This is why I am doing my rimfire suppressor on an F1, as at that time I didn't think the 07 was going to still be here. Where I live the CLEO just refuses to sign, so I have a Trust, and can efile. Lately, the last several months, I have missed a lot of work time due to my dad's ongoing cancer. So, as far as not being able to start the build until after the F1 versus now, based on how my life is happening, this means nothing. I have 5 weeks to brainstorm how I will build it. I know you don't know me, but I get pretty anal about such things, and I will change the design on this suppressor several dozen times. I just started on the rimfire can this week. It's going to use K's, and I'm making it out of titanium, so it will take awhile. Also, strangely enough, the multi-cal can has mostly been ignored here, built as an 07 build. I am building the rimfire can as an F1 build, and had way more interest.

[Gunfixr]

Well, BCJ did a thread on a mini suppressor, and in it he referred to a larger, but still compact suppressor, that was pretty quiet, at least hearing safe, but compact. I want a dedicated compact suppressor of my 16" AR rifle. My multi-cal suppressor works on it, but uses an adapter to QD to the flash hider. It's long, and the adapter adds a bunch of weight to it, there is a lot of POI shift. For this, I plan on just removing the flash hider and threading it direct. Hos compact unit was 5" long, and this was my original plan, but I stumbled upon that above picture and reflex design. BCJs short can only had a few baffles, and that is the plan with mine.
The rifle has freefloat handguard which is 2" OD, so yes, 2" is fine, as it just mates up to the handguard, especially if I reflex it all the way back, which is about 3" from the muzzle.
The rifle is running a midlength gas system, so it's not real high port pressure now, unlike a carbine system. With an OD of 1 5/8", and a blast chamber 2" long, the multi-cal can does not make a lot of gas come out the ejection port or around the charging handle. So, there may be some noise there, but it's not clearly noticeable as such.

It would be a relatively simple matter to machine the face of the baffle to have a lip around the OD, and simply make the first one deeper. I was thinking a small lip there on each of them anyway would be easier to weld than trying to catch the edge of the baffle, and would also make them seat better in the tube.



So, at this time, I am thinking 2" OD .049 316 SS tube. It will be a direct thread onto the muzzle, with a reflex of about 3", and approx 4" to 5" beyond the muzzle. I don't want it to go beyond 5" past the muzzle. The end cap will be the final baffle, and there would be somewhere between 2 and 4 baffles before that. The rifles' barrel is 16", I am thinking about 1 1/2" long blast chamber before the first baffle. The rifle is not full auto, and I don't generally do mag dumps.
I want to roll the gases back into the reflex, so instead of a straight cone, more of a narrow cone with a radius at the bottom, a short flat, which meets a radius around the outer diameter. The idea is to turn the gases 180 degrees.
I'm guessing that first baffle should be pretty thick, at least .090", or maybe .100"? It will be 316ss as well.

[Gunfixr]

Well, I got the F1 efiled for the 5.56 can.
There are going to be some changes, though. I acquired an AR lower in a trade deal, so I'm going to do a custom, sort of integral build.
The rifle will have a 12" barrel, with the can permanently affixed to end at about 17". Therefore, only one stamp. It will reflex back about 2" over the barrel.
Since it will be permanent, there will be no inner tube going back from the muzzle, the rear cap will be attached to the barrel at the back end, and there will be a support piece at the muzzle. Actually, it will have a short brake at the muzzle, to direct more back into the reflex.
Not sure yet of whether it will be serviceable or not, still working out the material details. The plan is to have it inside the front of a long handguard, so my original 2" diameter is going to have to shrink some, hoping for 1.75" od.

[c5_nc]

I finished my 5.56 and 308 Reflex builds I had referenced planning, they are 7.6" and 8.8" and when mounted add about 1.5 and 2.75" over a standard muzzle device. They ended up much quieter than I expected.

https://www.youtube.com/watch?v=ilUBYpK4nXA

https://www.youtube.com/watch?v=N9AILLCVjMo

[Gunfixr]

That suppressor looks familiar.
Did I see a thread on it here?

[Gunfixr]

Looking around at materials, 316 SS is available in 1.75" OD with a .065" wall, seamless tube.
Of course, 316 SS is also available as solid bar.
I can then simply plug weld the baffles in place through the tube, and weld both end caps on, to save some weight.

The rear cap will be threaded and pinned, back in front of the gas block. A brake will be threaded onto the muzzle, to direct more gas back into the reflex area. Probably just a single chamber with radial holes. Side vents, while larger, will only direct in two directions, while holes can direct all the way around. At the brake muzzle will be a flange that goes all the way out to the tube, and will also be plug welded in, giving a second point of contact with the barrel. Of course it will be vented.
Probably just cones out in front, however many seems reasonable with the decided blast chamber. With the brake, should be able to go shorter, maybe 1.5" long blast chamber.

I will be cutting off a longer barrel, for a few reasons, but this will allow the muzzle thread to be at least .625", making a good sized chamber in the brake easier. Barrel length will be 12", caliber 5.56mm, no full auto. Absolute silence is not required, just hearing safe.

Any reason all of this cannot be made with the 316 SS, and it hold up well?