New here. First Form 1 build...

[AceInTheX]

So I've been researching suppressors for a while now. Played around with some designs with a friend who has the Class 2 or what not. Most of his he made are from metal scraps and for .22LR's, though he made a couple to try on a M10-45. He also made one for an AR. I built a Mk Mod 1 SBR and filed the form 1 can stamp and got it back at the same time. I'm also very well researched into the legalities concerning firearms. I want to build my can out of 304 SS. I have handguards with a 1.8" internal diameter... As I'm going for max expansion volume, I'm thinking the OD of my can will be 1.75". I'm not concerned about weight. I'm trying to maintain a $500 budget and build a can durable enough to withstand full auto fire. Here's the dilemma:
1. I'm trying to source locally and trying to get "scrap" drop pieces so to avoid buying full 5-7' cuts.
2. I'm not sure what the minimum wall thickness should be. Iv'e read around on here and have seen minimum measurements of .75" for a .308 cal can. To me .125" seems thin for even a 5.56... Am I paranoid?
3. Would Sch 80 1 1/2 304 SS pipe with 1.9" OD and .200 wall thickness work once machined down to .125" thickness, leaving an outside diameter of 1.75"?
4. Does anyone know where I can source some 304 (or better metal) around NE Oklahoma or the Tulsa area?

[ECCO Machine]

Welcome aboard!

First, 304 is crap, to be avoided at all costs in my opinion where suppressors are concerned. It's not much stronger than A36 hot rolled mild steel, and just as soft. It's also a pain in the ass to work with, tough on tooling because it work hardens in the blink of an eye; if you don't have your speeds & feeds right, 304 SS is worse than gr. 5 Ti. The only real benefit to using 304 for anything is low cost and corrosion resistance, as it is one of the most corrosion resistant grades. Great for cookware and outdoor or underwater fixtures, but doesn't belong in guns or suppressors.

Assuming you have a lathe or access to one so you can use raw materials, a $500 budget is 100% titanium territory with cash to spare. You can buy a length of gr. 9 tube and enough 6/4 round bar to do a 9" long can for about half your budget. That said, I would run gr. 9 Ti tubing for the housing, but 17-4 stainless for baffles and end caps. 17-4 is a little stronger and a lot harder when heat treated than 6/4 Ti, even tempered 6/4 like AMS4965. You can use Inconel 718, too, but 17-4 is cheaper and easier to work with. 2 feet of 17-4 1.75" bar stock, plenty to do a 9" or 10" long can, will cost you around under $100 shipped if you shop around. I use 1.5" and typically pay around $25-$30/foot shipped. Check eBay. If you want really easy to work with, 416 SS machines like butter and can be made decently hard and strong, but it's nowhere near the mechanical properties of 17-4 PH.

Tube thickness-with gr. 9 Ti, I have 7075-T651 monocore full power rifle cans with sleeves as thin as .028", but those are featherweight hunting cans and not meant for heavy volume fire. I'll let them cool awhile after 5 rounds from my .25-06. My truly full auto rated critters (as in I've beat on them with back-to-back magazines from my 13" barreled .308 machine gun), I run .070" wall, and thin it to .050" in the center where there are no threads. My lighter weight cans, which can still handle rapid fire, are .039" wall. So, no, you don't need anywhere near .125" wall with gr. 9 Ti. Tiger metals is about the best source I've found for Ti tube; you can get your 1.75" OD tube with .087" wall from them for $54/foot plus shipping. And if it were me, I'd still thin that out in the middle to .050". Ti is lighter than steel, but it ain't aluminum, and the weight adds up.

In short, if you're not having to buy pre-fab tubes, caps, "80%" baffles and boosters, $500 is way more than needed, and you don't have to suffer a heavy pig of a can if you use the right materials. There's no reason your suppressor needs to weigh more than 20 ounces.

[AceInTheX]

Thanks. And thanks for the info... I had seen 304 used in a few manufactured cans so assumed it was a good material. I am not a metallurgist though I learned some of the basics in machine shop and Mig welding in 2005. I'm more of a blueprints guy though I want to go back to school and get my engineering degree. I don't know much about the property of metals. I did hear Inconel was good but hard on tooling. I have a few friends that are machinists but they aren't huge gun guys. I would probably have been told the same thing if I would have talked to them. The aforementioned friend and I aren't currently on speaking terms. I do have one question concerning legalities I guess. I have the blueprints of what I want built, I should be able to take Form 1, materials and blueprints to him to have a build party so to speak while he machines out the parts right? Though I will have to alter my blueprints some...

[ECCO Machine]

I do have one question concerning legalities I guess. I have the blueprints of what I want built, I should be able to take Form 1, materials and blueprints to him to have a build party so to speak while he machines out the parts right? Though I will have to alter my blueprints some...

Negative. You cannot contract the manufacture of form 1 NFA weapons, or of title 1 firearms. You could contract some things, but hiring someone to machine all your parts makes that person or company the manufacturer, and they'd be committing a felony to do so without a type 07 or 10 FFL and class 02 SOT. Take a look at ATF 2015-1.

[fishman]

I do have one question concerning legalities I guess. I have the blueprints of what I want built, I should be able to take Form 1, materials and blueprints to him to have a build party so to speak while he machines out the parts right? Though I will have to alter my blueprints some...

Negative. You cannot contract the manufacture of form 1 NFA weapons, or of title 1 firearms. You could contract some things, but hiring someone to machine all your parts makes that person or company the manufacturer, and they'd be committing a felony to do so without a type 07 or 10 FFL and class 02 SOT. Take a look at ATF 2015-1.

OP can build and complete a can, then send it to an 07/02 for a recore

[ECCO Machine]

I do have one question concerning legalities I guess. I have the blueprints of what I want built, I should be able to take Form 1, materials and blueprints to him to have a build party so to speak while he machines out the parts right? Though I will have to alter my blueprints some...

Negative. You cannot contract the manufacture of form 1 NFA weapons, or of title 1 firearms. You could contract some things, but hiring someone to machine all your parts makes that person or company the manufacturer, and they'd be committing a felony to do so without a type 07 or 10 FFL and class 02 SOT. Take a look at ATF 2015-1.

OP can build and complete a can, then send it to an 07/02 for a recore

Or a 10/02. But he's not talking about a recore; he's talking about paying someone else to machine parts for him for a form 1 build, which is a no-go. Those of us with 07/02 or 10/02 can build one to his specs, but then we have to engrave our info, serialize, and transfer on form 4 just like a production can. I'd be happy to build it for him, but it'll be fully assembled, engraved with "ECCO Machine" and entered in my book.

[fishman]

Op never mentioned payment

[ECCO Machine]

Op never mentioned payment

Read ATF 2015-1 and tell me if you'd want to be the test case for manufacturing without consideration. There has been much debate over the "engaged in the business language", but the verbiage within even states that the owner of the tools used is considered the manufacturer, whether or not he/she ever uses them to perform operations on or even touches the part.

OP-read that letter as I recommended, and you and your buddy with the machinery can decide if he wants to expose himself to potential felony charges for helping you.

[doubloon]

It's been discussed here many times as well.

[AceInTheX]

So I can't even use his machines? There are numerous machine shops here that will let you rent time on their machines... I can do just about everything on a lathe but cut threads... I should also state this is on a SBR and I'd be using a brake/FH combo of my own design as well... I found some 17-4 on eBay but not in the right lengths or diameter... My can will be about 10" with 4.975 over the muzzle brake and barrel... So at this point it looks like I can't even build the can. Got some bad info on another forum... If I can't even use some one else's lathe I'm screwed...

[fishman]

The intent of 2015-1 was to stop businesses from letting people use their machines to turn 80% lowers into unregistered receivers. These shops would often sell a customer an 80% lower, then rent them all the tools and instructions needed to finish their lower. The result was a business making money by pumping large numbers of unregistered lowers into civilian hands--all without registering as a manufacturer and paying the necessary taxes. Borrowing a lathe to create a REGISTERED form 1 firearm is a different, although similar, scenario.

There is disagreement about the interpretation of the law.
Everything below is not black and white.

At risk of sparking a debate, here's my opinion, which is close to the general consensus with form 1 builders:

If you borrow a machine, dont provide cash, goods, or services in return. This is easily interpreted as "business".

You ABSOLUTELY must be present during machining. Its a little more gray on whether or not your hand needs to be the ONLY one Turning the controls. You can't just kick back and watch someone else make your can.

If this is a one time deal and not a repeating occurrence then its hard to argue that the lathe lender is "engaged in the business of" making silencers.

I used my school's mill to port my K baffles. Anyone who claims X Y university is now engaged in the business of creating silencers is nuts, imo. ATF, come handcuff me.

If you want to remove all doubt, add the lathe lender to your trust (or LLC) as a responsible person and then they have every right to be involved in the form 1 process. Hopefully you didn't apply as an individual.

I'm not advocating anyone commit a felony, however--when a legal gray area arises, if you do what you believe is right, behind closed doors, the ATF will not know and you will have a clear conscience.

[AceInTheX]

Thanks all for the info, I have read of guys using "________ University" to machine out parts for their builds and hence some of my confusion. Now I just need the materials. Now that the legal stuff is cleared up, I have some technical specs questions...

First, how do I post images?

[John A.]

upload photos to a hosting website.

Like imgur or anything but photobucket.

then after they're uploaded to the hosting place, move the cursor over the image and right click and copy the properties, then come here and use the Img tab just above wherever you type your message and you paste the photo properties between the [img]and the[/img things.

[ECCO Machine]

Now that the legal stuff is cleared up, I have some technical specs questions...

Clear as mud, anyway. Fishman is correct in that the intent was to stop the CNC build parties, where the end user basically put an unfinished receiver in a pre-programmed and set up CNC, then pushed the start button. Problem is the vague language of 2015-1 that leaves it open to interpretation. The common wisdom is that friends using each other's equipment without consideration is probably good to go, but there have been no official rulings or precedents set. Using a machine belonging to a shop that is in the business of machining parts for profit? That's pretty iffy; even if they're not engaged in the business of making guns and gun parts, they are a business. And if there is any consideration (money/goods/services) for the use of the machine, it's absolutely a business transaction.

I used to rent people time on my machines to finish their lowers. $50 a pop, they paid for any broken cutters, I supervised to make sure my machines weren't abused. It was profitable for me in my spare time, and they got a receiver finished more accurately and cleaner than they would with a jig costing twice as much or more. Then 2015-1 came down, and I had to cease that operation, cancel the appointments I had booked. People were pissed, but I wasn't gonna risk criminal charges, fines or jail time for them.

[AceInTheX]

upload photos to a hosting website.

Like imgur or anything but photobucket.

then after they're uploaded to the hosting place, move the cursor over the image and right click and copy the properties, then come here and use the Img tab just above wherever you type your message and you paste the photo properties between the [img]and the[/img things.

Thanks.

[AceInTheX]

https://imgur.com/a/Fggp3
This is the basic design for my muzzle brake/FH combination mount...

[AceInTheX]

Should I use the "embed" button on Imgur?

[AceInTheX]

It is a 2 piece design, the first part screws onto the muzzle of the rifle and has threads at the rear that will be under the handguards and against the gas block. The second part is the actual muzzle brake/FH combo and screws onto the first. What I need to know is if I need to leave the space on the inside of the first part toward the rear of the threads for a crush washer. I will have flats machined onto the outside for use of a wrench. I thought about machining a groove at the front of the first part that would line up with a groove at the rear of the second that a shim would fit in to keep them aligned and attached to each other... The 5.025 measurement is how much the actual suppressor would be forward of the brake if I had the overall suppressor length at 10"...

[fishman]

DO NOT USE A CRUSH WASHER

why not make both of those parts one part?

[Hannibalbarca]

DO NOT USE A CRUSH WASHER

why not make both of those parts one part?

Is there a reason you can’t use a crush washer? I mean you can use them on QD brakes and flash hiders and a suppressor would go on that muzzle device so what’s wrong with using a crush washer on a direct thread can?

[doubloon]

...
Is there a reason you can’t use a crush washer? I mean you can use them on QD brakes and flash hiders and a suppressor would go on that muzzle device so what’s wrong with using a crush washer on a direct thread can?

Maybe it's OK to mount a JJFU can with a crush washer.

https://silencerco.com/wp-content/theme ... _small.pdf

Crush washers are NOT recommended as they do not crush uniformly and WILL
cause improper mounting and baffle strikes. SilencerCo recommends the use of a peel
washer or the included shim kit if any indexing of the mount is required.
For proper alignment, it is essential that the muzzle brake seats against a 90°
barrel shoulder. The flash hider/muzzle brake should be torqued to 20–30 ft-lbs.
Use of Rocksett™ or Loctite Red 271™ is recommended.

[AceInTheX]

Thanks for all the info guys.

[AceInTheX]

DO NOT USE A CRUSH WASHER

why not make both of those parts one part?

I figured with the threads inside the mount, I wouldn't be able to easily machine further down inside...

[AceInTheX]

Welcome aboard!

That said, I would run gr. 9 Ti tubing for the housing, but 17-4 stainless for baffles and end caps. 17-4 is a little stronger and a lot harder when heat treated than 6/4 Ti, even tempered 6/4 like AMS4965. You can use Inconel 718, too, but 17-4 is cheaper and easier to work with. 2 feet of 17-4 1.75" bar stock, plenty to do a 9" or 10" long can, will cost you around under $100 shipped if you shop around. I use 1.5" and typically pay around $25-$30/foot shipped. Check eBay.

I still haven't purchased materials as I've only found enough of the 17-4 t build the core and FH/mount. I was reading though that 17-4 doesn't do well with high heat over 600*... As A suppressor under rapid fire can easily obtain temps up to 1200*, are you sure this is a good idea?

[T-Rex]

While suppressors can get hot, they don't hold the extreme temps for extended periods. This is what would be detrimental. At 1000F (for 30min) H1150 will retain more of its room temp UTS than Ti-6Al-4V.

Watch some torture test vids.
You really need to try and break these things.
Here'sn one of my favorites