Barrel Shroud to Avoid SBR Designation

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MMH
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Barrel Shroud to Avoid SBR Designation

Post by MMH » Tue Nov 05, 2019 6:01 pm

I will be cutting down my 16” barrel on my 300BLK Sig MPX to somewhere around 9” and permanently installing a long muzzle shroud to keep the ‘barrel length’ over 16 inches. The barrel will be threaded (5/8-24) and the shroud have a large enough ID so that I can install a suppressor inside the shroud.

To keep the weight as low as reasonable, I want to use an aluminum tube (6061) that has an 1.75” OD & a 0.065” wall thickness. Most of the shroud would be protected by a rifle length free floating hand guard. The tube will be welded to a thicker backing plate (similar to a xxx on a suppressor). This backing plate will be threaded to the barrel & then silver soldered on. Alternatively I can pin w/ a steel pin & weld AL over the pin. In addition, the shroud will be drilled with a bunch of ½” holes throughout it’s length (similar to what a WWII SMG barrel hand guard looked like). This will not only lighten the shroud, but remove any doubt that it is a suppressor.

Will the above meet ATF requirements? Is a thickness of 0.065” sufficient. I can increase to 0.083” or even 0.125” (although at .125” I would have to increase the OD to 2” for suppressor clearance). Would pinning/welding be permanent (I think I prefer this silver solder).

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John A.
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Re: Barrel Shroud to Avoid SBR Designation

Post by John A. » Wed Nov 06, 2019 8:18 am

It is legal to permanently affix a muzzle attachment onto a short barrel to reach the minimum barrel length. Silver solder, welding, or pin/weld is accepted methods of achieving such.

I remember someone doing the same thing on Ruger 10/22's a few years back.
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Re: Barrel Shroud to Avoid SBR Designation

Post by poikilotrm » Wed Nov 06, 2019 12:02 pm

Welding can mess up your barrel. Pinning is easily seen by a cop, and not easy to remove by twisting. You have to be sure that you make it hard for the cops. Remember, Sheriff Mark McClure manufactured an SBR in my house using my tools, then charged me with having an SBR, and tried to get the ATF to charge me as well.

The problem with what you are proposing is that it is illegal. You are planning to chop the barrel, then add the fake supressor. You may not do this without first begging massa's permission. Even though you are instantly restoring it to a legal length, you have violated federal, and most likely state, law in the process.
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John A.
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Re: Barrel Shroud to Avoid SBR Designation

Post by John A. » Wed Nov 06, 2019 2:57 pm

I don't agree with that statement at all. You can't pin it before it's cut shorter. :roll:

Just don't put the upper and lower together while it's in its' shortened form before completing the work making it a permanent attachment. It's not rocket science.
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fishman
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Re: Barrel Shroud to Avoid SBR Designation

Post by fishman » Wed Nov 06, 2019 5:04 pm

poikilotrm wrote:
Wed Nov 06, 2019 12:02 pm
.The problem with what you are proposing is that it is illegal. You are planning to chop the barrel, then add the fake supressor. You may not do this without first begging massa's permission. Even though you are instantly restoring it to a legal length, you have violated federal, and most likely state, law in the process.
This is blatantly false. Remove the barrel. Then chop it. Then attach a shroud. Then install the barrel back into the gun. 100% legal.
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MMH
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Re: Barrel Shroud to Avoid SBR Designation

Post by MMH » Thu Nov 07, 2019 8:13 am

John A. wrote:
Wed Nov 06, 2019 8:18 am
It is legal to permanently affix a muzzle attachment onto a short barrel to reach the minimum barrel length. Silver solder, welding, or pin/weld is accepted methods of achieving such.

I remember someone doing the same thing on Ruger 10/22's a few years back.
At this point I am planning on a aluminum shroud. It would be drilled, pin driven in and both ends of the hole welded up (obviously w/ aluminum) to seal the pin inside. That way if I ever have to get at the muzzle, I can machine off the weld and drive out the pin. Yes, I will destroy the shroud, but at least can get at the barrel.

Do you have comments on this method and using aluminum? How thick of a shroud do you think I need. I am hoping to stick to 0.065" to save weight

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John A.
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Re: Barrel Shroud to Avoid SBR Designation

Post by John A. » Thu Nov 07, 2019 8:16 am

.065 is more than thick enough.

Even .058 would do. Even thinner will than that if you're not hard on your stuff. But for the occasional ding and bump .058 is fine and would be a touch lighter than .065".

And I agree, weld over the pin. And if you ever do need to remove it, would be easier.
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Re: Barrel Shroud to Avoid SBR Designation

Post by poikilotrm » Thu Nov 07, 2019 10:11 am

fishman wrote:
Wed Nov 06, 2019 5:04 pm

This is blatantly false. Remove the barrel. Then chop it. Then attach a shroud. Then install the barrel back into the gun. 100% legal.
Removing the barrel to make an SBR is still violating the law. Nobody is going to know, and nobody but the cops cares, but it is not legal.
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John A.
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Re: Barrel Shroud to Avoid SBR Designation

Post by John A. » Thu Nov 07, 2019 10:38 am

Reading comprehension is critical.

He said he was pinning and welding an extension onto the barrel so as to NOT create an SBR which is entirely 100% legal, and there are ATF guidelines for doing so.

As in the silver solder (braze), weld, or pin and weld. All of which has been discussed here in the topic.

If you have access to some law that says otherwise, post it up.

Otherwise, you're just plain wrong.
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Re: Barrel Shroud to Avoid SBR Designation

Post by T-Rex » Thu Nov 07, 2019 10:46 am

I'm with the crowd, on this one.
It's not an SBR until assembled, this is from ATF's mouth and case law.
Also, there's no intent to build an unregistered NFA firearm, as he's pinning it to legal length.
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Re: Barrel Shroud to Avoid SBR Designation

Post by poikilotrm » Thu Nov 07, 2019 11:15 pm

I bow to the hive.
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Re: Barrel Shroud to Avoid SBR Designation

Post by VX666 » Sat Nov 09, 2019 1:54 am

Legal practice and legal technicality are two different things, you won't know what will happen until the design is put to legal challenge.

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Re: Barrel Shroud to Avoid SBR Designation

Post by John A. » Sat Nov 09, 2019 1:49 pm

:roll: Sigh...

This is seriously one of my pet peeves. For many years, a lot of people would ask honest questions in regards to NFA compliance. Then there would be folks spouting off all kinds of urban myths and just wrong info in general.

If you follow the legal guidelines below, there is no legal disrepency to challenge.

reference page 1 right underneath of the first photo if anyone cares to look it up for themselves. Like I said earlier, it's not rocket science and there is no reason to make it any harder than it has to be.

https://www.atf.gov/firearms/docs/atf-n ... 2/download


The ATF procedure for measuring barrel length is to measure from the closed bolt (or breech-face) to the furthermost end of the barrel or permanently attached muzzle device. Permanent methods of attachment include full-fusion gas or electric steel-seam welding, high-temperature (1100°F) silver soldering, or blind pinning with the pin head welded over. Barrels are measured by inserting a dowel rod into the barrel until the rod stops against the bolt or breech-face. The rod is then marked at the furthermost end of the barrel or permanently attached muzzle device, withdrawn from the barrel, and measured
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