Muzzle pinning

R

redlightrich

New member
Hello all, I can't find the exact written passage in regards to making a muzzle brake permanent.

I realize that common practice is to drill a divot in the threads of the barrel, add a steel pin and weld it closed.
An agent with a wrench should not be able to remove it.

What if the hole thru the muzzle brake was filled with a pin then closed with steel mixed epoxy? It also would require special tools to remove. It would be permanent to most individuals without special equipment.

Does the law require welding specificaly or do they vaguely state permanently attached?

I own a mig, gas and arc welder. I am basically trying to understand the law. This is from a NJ perspective.

Thank you

Rich
 
1) move out of NJ and dont worry about it ever again, you can follow my dust trail out :cool:

2) where are you located, I have a local smith in the south jersey area that can take care of it for you or answer your questions if you want to DIY the project
 
Epoxy is not sufficient to retain the pin if a wrench is put on the brake. Regs say the brake must be permanently attached, and epoxy is not permanent. Just put the pin into the hole, seat it with a punch, and TIG it in place. If you think you might want to take the brake off some day, just leave the little bump from the TIG so you know where to start to drill the pin out.
 
I don't believe that epoxy is considered a permanent method of attachment. I'm sure most epoxy can be broken with a sufficient twist from a torque wrench. Another option, if you can't or won't weld it, is to use a high temperature (1,100+) silver solder. This is considered a permanent method of attachment per ATF. I don't know how your state will consider it, if you're doing so to meet a state law. They can have different definitions or interpretations than the Federal government
 
NJ laws are whacked, period

No disrespect to the others who have answered but they don't live here and don't know what they are talking about, especially when bringing in mentions of the ATF when this is not s federal issue, its a state issue.

Have a local smith take care of it for you and be done with it. My smith is a retired NJ state cop so he knows what you need to have done to stay within the law
 
Hello all, Grizz I agree. I should and I am considering running. I have welding equipment a plenty. I however, thought of a method that would not give under the stress of a wrench.

Drill the muzzle brake with a #30 or there abouts
Index the brake
Use the pre drilled hole in brake as a guide and drill a .030 index into the threads on front of the barrel ( plenty of meat here to do this)
Tap the brake with 8/32 threads
put in an allen set screw ( aprox 5/32 lenth) , and tighten lightly as to not distort barrel
Put molded super epoxy in hole covering the set screw hole

I promise that a wrench can not remove this brake, and it would require a grinder to remove the epoxy and a drill to get the set screw to back out being the allen key slot will be full of epoxy. I would think that this method would be about as permanent as weld or silver solder.

I agree, if a traditional pin were used, the epoxy may "yield" to the wrench a tad, and cause movement of the brake. This would not bode well.

Using the relief and set screw, the brake will not budge. But based on all the replies here, I won't tempt fate and will weld it.

Just a last thought of the epoxy, I have used quality epoxy to repair delicate castings. When cured, I was able to machine flat using a broach, and drill and tap. When finished, only the darker color gave away it was not the original material. Good stuff.

As always, thank you for your thoughts

Rich
 
A looooong time ago the "Shorti" barrels had the flash suppressor silver soldered on, as already mentioned. I would not be afraid to use soft solder. Ever try to hammer off a Mauser sight assembly?
 
The OP didn't try to just epoxy glue the brake on the muzzle. A pin would be used. It was the method to fix the pin.

I think the method will strong enough for the wrench test. But it is still not kosher as it is not permanent enough.

Soft solder is not permanent enough either, if I remember correctly. It would be either hard (silver) solder or weld. I don't like silver soldering. Too hot and too slow, and will affect barrel's heat treat. Quick tig weld is the way.

-TL
 
From what I have seen, ALL the chamber ends (Barrel extensions) were silver soldered on the military models. Pull the alignment pin out of the extension on some old barrels and check it out. What is the difference whether you use soft solder or silver solder? Both can be removed with heat.
 
Put molded super epoxy in hole covering the set screw hole
Click to expand...

You will be in violation of the GCA, and be in possession of an unregistered SBR if your barrel length (as measured from the boltface) is less than 16".

From the NFA Handbook, here:
https://www.atf.gov/firearms/docs/atf-national-firearms-act-handbook-chapter-2/download

The regulation is clear, ATF even took the effort to underline it:

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.
Click to expand...

There is no vague "standard" for the attachment being able to resist "X" amount of torque.
 
Hello again, and thanks for all the input. I do have silver solder ( the 1145 degree type) but in the end, I would up using MIG weld. It allowed me to weld up the pin hole without super heating the barrel. I attached the ground right on the muzzle brake and it was welded in seconds.

I have a 20 inch barrel, so length is not an issue. It is having a threaded barrel with a pistol grip conspicuously protruding from the bottom. NJ is not too friendly on this type of rifle.

Does the law require that I grind the weld perfectly flat? I currently have a perfect round bead that I just as soon paint black and call it a day.

Can I leave the weld obvious or must it be ground and blended?

Thank you

Rich
 
The regs require silver solder or welding.

Beyond that, there isn't much that matters. You can leave the bead, grind it but leave it unfinished, grind it and finish, or even engrave around it with an arrow and instructions: "Drill here for SBR!"
It matters not.

On my 14.5" .475 Tremor barrel, I blind-pinned the brake with the securing weld tack right on the bottom of the barrel. There's a "cute" little bump there that got hit with some black Sharpie, and I have no intention of grinding or blackening in any other way. Perfectly legal.
 
Since you're worrying about a state law, I think you need to be looking for clarification from state authorities. What the ATF considers permanent may not be the same as what your state does. I can't imagine a situation where a good weld wouldn't be considered permanent whether it was left as a lump or ground flush, but I'm not a NJ state authority.
 
Thanks very much Franken!! I am leaving my weld exposed so I can easily locate it if needed . I already pulled out the black sharpie, and I should be off to the range to try my new M16 clone ( without the burst ) soon.

I appreciate everyone's help!!

Thank you all
 
I was just looking at NJ compliant ARs from Stagg, and I could be wrong, but it appears they paint their pin welds yellow? The LGS has about 5 and they are all this way. I didn't examine them, but the way they are in the rack displays the underside and all the muzzle brakes have this yellow dot dead center at 6 oclock on the threaded rim of the brake. The only thing I can guess is they are calling attention to where the weld is for a few reasons.

And yes, I do agree it is more up to NJ law than Federal, but my thought is, if I am ever in a situation where they are testing the integrity of my pin job, things have already gone wrong. I will try and avoid that best I can.

Thank you all for the insight and humor. Great place tfl!!!!!

Rich
 
And yes, I do agree it is more up to NJ law than Federal, but my thought is, if I am ever in a situation where they are testing the integrity of my pin job, things have already gone wrong. I will try and avoid that best I can.
Click to expand...
Yep.
And if your "permanent" attachment is being tested, the barrel and muzzle device are likely both toast, anyway, if pinned. The few reports available online say that the ATF clamps the barrel in a vise and puts a BFW (or pipe wrench) on the muzzle device. It is turned off with whatever force is necessary, and the determination is made after the fact: Legal or not legal.

So even if it was legit, now your barrel threads have been annihilated, the muzzle is probably out of round, and the muzzle device is completely screwed.
Silver-soldered muzzle devices that were done well generally don't move. But pinned muzzle devices get turned off and ruin everything in the process.


Just keep it legal and avoid doing stupid things that will make the ATF want to crawl inside your rectum for a closer look.
 
I agree that a pin forced into a "divot" in the threads can(and most likely WILL) be defeated by a BATFE(or some other LEO type) gorilla with a pipe wrench. At that point, the only possible way the muzzle device will stay intact is if the "divot" is deeper than the threads and a hardened "pin"(little piece of drill bit or some such material)driven into the actual barrel wall.
The Feds will destroy a $50K vehicle looking for a tiny bit of drugs so would expect no compunction about destroying a $1K firearm to prove their point(or suspicion of something illegal). Good intentions won't prove up in court.
 
I guess we have been talking about lock pin driven radically through the muzzle device and into a blind hole in the barrel wall, so it has only one divot when welded up.

How about a lock pin in a "tangential" through hole, similar to the barrel pin in some 0.22 rifles? It will have two divots when welded up though. I think it is much stronger.

-TL
 
tangolima, that's how the brake I mentioned above was pinned.

The hole starts at 6 o'clock on the brake, but angles to the left side. So the pin actually runs from 6 o'clock (welded) to about 8 o'clock (blind).

I've heard it referred to as a "blind cross-pin" by some machinists in the past, but I don't know if that's the proper term.
Due to the angle of the hole, the weld bead has to be a little larger; but I don't care about a minor cosmetic issue on an AR.


Here's a quick visual with a junk .22 rifle receiver, for anyone not following:
-Representing a view from the muzzle. And, of course, the end of the punch would not extend through the far side on a real pin installation.

attachment.php


It's more intuitive to go straight across, but I wanted the bead to be at 6 o'clock on mine.
 

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