Solvent trap kits

BigWaylon

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Note(s): solvent traps are not NFA items, but can be converted into NFA firearms; this is no different than legally owning an AR pistol or a 16” AR and wanting to convert it into an SBR; you need to be aware of all NFA regulations, and do not modify anything without an approved Form 1; remember, there are also engraving requirements that must be met for all NFA items, and they’re even more involved for a firearm you make by starting with a non-firearm (similar to starting with an 80% lower); feel free to ask any questions you want relating to this topic in the thread, or send me a PM and I’ll answer if I can


I made a comment in chat last night about DIY silencer kits and it resulted in a couple PMs last night and this morning. I got my latest two kits in the mail today, and figured I’d post some pics and talk about some options for a minute.

I currently have seven Form 1 cans. The first six were done at the same time and are somewhat similar. I made two “sets” of 3. One set was Ti tubes and one set was SS tubes. All had SS ends. All the baffles were formed freeze plugs. These are your basic D-cell (named after Maglite tubes) sized silencers you’ll see when looking around online. I bought a pile of $.69/ea freeze plugs and formed them on my kitchen island with a 6-ton HF press. Drilled the hole and used a Dremel to clip them. They don’t look too bad.

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I averaged ~$150 into each one of them. Used the air dry high heat (C-series) cerakote. The SS set has different adapters. One is 1/2-28, one 5/8-24, and one is YHM. They’re all the same externally, so I can swap the mounts between different length cans and never have extra parts. All the baffles in all six are big enough for .30 cal. The Ti cans all have YHM adapters.

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I had the SS tubes turned down between the threads to reduce weight. There’s a 7”, 8” and 9” of each style. I was lucky enough to talk my way into a testing session when I went to visit Mike and Henry at Rugged Suppressors. The Ti (Gray) cans were freeze plugs and some spacers. The SS (Burnt Bronze) were as slammed full of freeze plugs as I could get them. The SS ended up being ~5dB quieter than the Ti. All of them were in the same ballpark as some SiCo and YHM commercials cans I took with me...sometimes a little quieter, sometimes a little louder.

I also had the opportunity to go shoot with Joshua from Capitol Armory and Jeremy from Silencer Shop, took some of them with me. One trip to Austin for business, two separate trips to the range with them. Both were very interested in seeing how freeze plug can performed, and both admitted they were blown away by the tone, backpressure level, and overall performance. $150 sounded about the same as $900...obviously no real warranty and not as short/light as current offerings. But it was good learning experience for me.

The 7th one I have is a 2-piece monocore (similar in design to a Gemtech 300BLK silencer) that’s dedicated to my AR57 upper. It wasn’t a kit, rather a project I got some local help on. It’s a Ti tube and Ti core, roughly 1.25”x6”. It was over three years from submission to the time I actually had it in my hands. Mainly because I had a Spectre on the rifle already, and didn’t put a lot of effort into getting the help I needed to finish it.

This brings me to my current projects. I originally asked the guy for three rimfire cans. I was going to keep one and two other members here wanted the others. We opted for the cheap route, since they would be for 22LR only. Aluminum tube, I honestly don’t remember on the ends, and a “baffle stack” that was staggered length Ti spacers, 2 SS cones and 4 Ti cones. Looks similar to this except the tube is raw Al and actually has the factory specs printed on the outside still.

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At some point after I ordered, I test fit my AR57 F1 can on my 15-22, and really liked the way it looked...better than the 1” Spectre.
 
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So, I checked with the machinist I’ve used, who is real popular in the F1 silencer world. Same one that made the Ti tubes and all the end caps on the first six. (The SS tubes from Apogee). He happened to have some 1.25” Ti tube ready to go. I canceled my first kit and said I wanted two 1.25” instead. One would be for 22, and one for 9. I specified 6.5” long, 7 baffles in each, evenly spaced. One would need a 1/2-28 DT adapter and the other a 1/2-36 DT adapter. I told him it didn’t really matter to me as far as material, but he went with full Ti...fine by me.

The aluminum tubed kits came in two months ago. The two for me showed up today. Open the box, started to unwrap one, and paused for a pic.

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The tubes are the same, the end caps are the same, and the spacers are the same. The direct thread adapters are only different in the thread pitch. The radials are sized differently for 22 vs 9. I laid everything out and had this:

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You can see the face of the cone is smaller on the kit on the left. Each radial has a rim on top and bottom of the skirt, so the spacers slide over it and seal the stack off from the tube.

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When you stack it all up, you get this:

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Here’s a shot of the 15-22 with the Spectre:

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And here’s what the larger OD can will look like:

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The ID on the 9mm upper I want (4” barrel, 6” rail) is almost identical to the 15-22...so the fit should be similar, although it’ll stick out of that rail more than it does on the 15-22.

What’s left:
1. File EForms next week. Already have them filled out online, just need to pay and submit. Wanted to make sure the tube fit the 15-22 before I submitted.
2. Visit @TARHEELSTATE to get them engraved.
3. Visit @Magdump to get them cerakoted (high temp flat black)
4. Visit machinist to get bore opened
5. Assemble and shoot!!

If you actually have the ability to run a lathe yourself, you could easily build your own for <$100. The stamp is the same $200. But an EForm 1 is likely to be approved in <30 days, compared to 8-12 months for a paper Form 4.

Anyway...figured that would be enough to get a conversation started.
 
...and before anybody asks about having somebody else open up the bore, I’ll quote the NFA Handbook. The 3rd paragraph is the important part.

Section 6.4 Approval of Form 1. Non-FFL/SOT’s may seek approval to manufacture an NFA firearm (e.g., short-barreled rifles, short-barreled, shotguns, wallet guns, etc.) via submission of an ATF Form 1. Upon receipt of the completed Form 1, ATF will process the application and, if approved, a tax stamp will be affixed to the original of the form and the approved application will be returned to the applicant. Approval by ATF will effect registration of the firearm to the applicant. Upon receipt of the approved application, the applicant may make the firearm described on the approved Form 1. The approved form must be retained by the applicant and made available at all times for inspection by ATF officers or investigators. Note: Under no circumstances may the firearm in question be made prior to receipt of the approved Form 1.

The approval of the Form 1 application authorizes the applicant to make the firearm. The approval does not authorize the applicant to convey or ship the firearm to another person to manufacture the NFA firearm. If another person will manufacture the NFA firearm, the other person would be the maker and the application must be submitted by that person. Subsequent to the making, the firearm could then be transferred, subsequent to an approved Form 4 application, to the person who wanted the modification to be made.

If the applicant on the Form 1 lacks the skill, ability, and/or equipment to manufacture the NFA firearm, the applicant, after receipt of the approved Form 1, can have the firearm created or modified at a premises other than shown on the approved Form 1 as long as the creation or modification was done under the direct oversight of the applicant, thus having the applicant retain custody and control of the firearm. If the location is outside the applicant’s State and the firearm being made is a short barreled rifle, short barreled shotgun, destructive device, or an unserviceable machinegun which is being reactivated, the applicant will also need to request permission to transport the firearm interstate as required by 27 CFR 478.28.
 
Here's my take on an F1 can. Also built from a "solvent trap" kit. Entirely Ti except for the spring. I bought the tube and end caps from an online source. The end caps needed to be drilled and tapped. A friend with a lathe did that for me one afternoon after the stamp arrived.

Instead of freeze plugs, my baffles are Titanium valve spring retainers (auto engine part) and Titanium stock that I cut for spacers. The spacers are needed because the VSRs don't have a skirt like the freeze plugs. The only non-Ti part is the spring that I'm using to compress the innards for stability and to use as a blast chamber.

The biggest PIA was cutting the Ti spacers. I crushed more than I made.

The VSRs have an aperture of .491 and the end cap is bored to .419". Entirely too large for my 9mm SBR that it rides on, but I was being overly conservative about concentricity.

Total weight 13oz

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VSRs before/after:

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Oh yeah...now that @Tim mentioned it, I do have VSRs for blast baffles in the first six. Forgot that fact. :oops:

Edit: I believe mine are M300 steel, which I figured would take the blast better than the softer FP steel.
 
Awesome 12$ postpaid kits on ebay right now....
 
The filter storage system seems quite well made
 
I’m not seeing that one specifying the aluminum used...

With these coming from China, I would not trust their description of aluminum used. We had a small injection mold insert made in China and specified a P-20 pre-hardened steel. When it came in, it was a tight fit so the tool maker was using a lead hammer to get it in and the lead hammer deformed the steel.
 
This is Very informative all around. Thanks BigWaylon !

The key to all this is getting it done right like you've illustrated, thanks.
 
I did file my two F1s in EForms on Monday 6/24.

I ended up buying the PSA 9mm upper that has a 4” barrel and 5” handguard. It was in stock, but the 4”/6” combo was not. Went ahead and bought that one because I had an idea to swap to a longer handguard. Put a WTB ad on ARF for the 7” or 9” rail, and within ~6 hours had somebody contact me with a 9” one available. We agree on a price and it showed up today.

I was pretty sure I’d need to have the end of the rail cut off so be able to get a grip on the silencer. The guy measured the “smooth” section at the end and said it was ~1.25”. I think that’ll be enough. Machinist said cutting it about where the red line shouldn’t be an issue.

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I’d asked him to measure the ID before he shipped it and he said it was a little over 1.3”, which is what I was told the 5” & 6” rails were. It showed up today and there’s a slight problem. It’s only big enough for a 1.25” tube to fit inside for that smooth section. Then it’s a little squared off. You can see what I mean in both of these pics:

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The outside of the rail is the same all the way down, so there should be enough material to bore out the inside enough to accept the tube. Sent pics to the machinist this afternoon to ask.

Hoping I get approvals in ~2 more weeks. In the meantime the upper should show up in a couple days and I can figure out exactly how much of this 9” rail needs to be cut/bored. And after approval, I can start on the radials. Looking at .275” for the 22LR and .410” for the 9mm...both double-clipped.

I think this 9mm build has potential to be really compact and fairly lightweight. Even grabbed four 20rd mags (Colt style) to help with size & weight.
 
Super cool and thank you a TON for this.

A question, for pistol like a Scorpion, shooting subs and 115fmj, would you go with an aluminum tube and steel baffles or no?
 
Super cool and thank you a TON for this.

A question, for pistol like a Scorpion, shooting subs and 115fmj, would you go with an aluminum tube and steel baffles or no?
Personally, for me, the difference is in the cleaning. Not the performance or durability. Quite a few commercial manufacturers use aluminum for pistol cans. It just limits you in how you can clean them.

An aluminum tube, with steel baffles...especially a shielded stack, would work just fine. If you found a place that offered this kind of setup, having two steel baffles and the rest aluminum would reduce the weight a bit.
 
Anyone see any larger diameter tubing, as in larger than 1.75 diameter?
 
I'm doing one in 9mm. Stainless steel direct thread end and first two baffles. Titanium 5.5" tube, the other 5 baffles, spacers, and end cap.
I can't wait for my stamp to get approved!

CHRIS
 
Do you need to do that little cutout or is just drilling the holes enough?
The clip makes a decent difference with suppression level in a lot of circumstances. A single clip tends to give a little more POI shift, while a double decreases the shift. Doesn’t really matter to me because I sight everything in with the silencer attached and leave them that way.
 
The clip makes a decent difference with suppression level in a lot of circumstances. A single clip tends to give a little more POI shift, while a double decreases the shift. Doesn’t really matter to me because I sight everything in with the silencer attached and leave them that way.

Single as in one per baffle, or one per supressor?

Guessing the poi is towards the clip due to pressure differences?

If i go your route and use a demel is it super critical for them to all be as identical as possible
 
Single as in one per baffle, or one per supressor?

Guessing the poi is towards the clip due to pressure differences?

If i go your route and use a demel is it super critical for them to all be as identical as possible
Per baffle. You’ll find several commercial cans where they skip the blast baffle.

Some say line up the clips. Some say rotate them. I’m not 100% sure if it towards or away from the clip, as I’ve never tested it. I’d get them as identical as possible, but my bores aren’t even all the same size due to variances when forming and drilling.
 
I’d get them as identical as possible, but my bores aren’t even all the same size due to variances when forming and drilling.

Yeah used to have a buddy cut is freeze plug cans by adding a spacer and shooting through each baffle individually
 
I saw this today on youtube and went to the manufacturer's website. I don't know how they are selling this in it's configuration. Looks like a suppressor to me.
FWIW...here are my initial thoughts:

1. The term “spaced cap” makes me laugh
2. Those baffles look like a horribly inefficient design
3. I buy that as a “solvent trap” more than most offerings...because the ones with undrilled cones wouldn’t fluid or a bore brush go more than an inch into the tube
4. The moment you drill the end cap, I see multiple NFA violations
 
This has me reallly thinking about building one of these, especially after reading the form 1 tutorial...

What are preferred or better baffles? Where you guys scoring these or VSRs? Preference on steel vs aluminum? Is it strictly weight considerations?
 
This has me reallly thinking about building one of these, especially after reading the form 1 tutorial...

What are preferred or better baffles? Where you guys scoring these or VSRs? Preference on steel vs aluminum? Is it strictly weight considerations?
I bought my VSRs off various forums. Only have them for blast baffles in freeze plug cans.

I would consider aluminum for rimfire or pistol...but only use steel (or better) on a rifle caliber.

It’s not just weight Al is an option. It’s also durability as well as the number of options for cleaning.

My last three have all been 100% Ti.
 
I will be buying a 22 lr and a .223. Thanks to your information, they will be 100% Ti. I was thinking about a form 1 build, but considering the cost of the tax stamps and that I only want two, I am buying something that will stand up to use and cleaning.
 
I will be buying a 22 lr and a .223. Thanks to your information, they will be 100% Ti. I was thinking about a form 1 build, but considering the cost of the tax stamps and that I only want two, I am buying something that will stand up to use and cleaning.
Not sure what components you’re using, but if there’s an option I’d have the first two cones in stainless so you could rotate them as needed. The rest of the stack could be Ti. But that’s just me.
 
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