What Does A Gunsmith Do To Pin And Weld?

If you live in the US and are a shooter, chances are you are fully aware of the 16″ barrel length requirement by the ATF. The regulation presents a bit of a problem for some shooters thanks to the cheap and available 14.5″ barrels coupled with the knowledge that our general military service rifle features the same barrel length. Many buyers fall into the trap of using one for their build without thinking through the need for a permanently attached muzzle device that brings the barrel length up to the required 16″ in the ATF’s eyes.

I fell into the trap of a 14.5″ barrel thanks to a sale that Bravo Company was running for 14.5″ mid-length, light weight, chrome lined barrels at about half what the normal price is. Before buying it I thought to myself “this shouldn’t be too hard to pin and weld myself” and convinced myself to hit that checkout button. The one thing I didn’t account for was my drill press dying while waiting on the new barrel leaving two options, buy a new drill press or take it to a gunsmith. Since I hardly used the old drill press anymore, the choice was an easy one.

I called my friend Joe who is a gunsmith and asked what kind of bourbon it would take to bribe him to pin and weld a muzzle device to my shiny new barrel. Thankfully his taste in spirits aren’t exactly highfalutin, and I was able to have the work done for a mere gallon of the most moderately priced bourbon on the shelf. Joe was even kind enough to allow me to take photos in his humid, camera destroying shop so I might share the process with TFB’s readers.

Joe started by removing the muzzle device from my assembled upper so that he could measure what depth he needed to drill to, degrease the threads, and LocTite the muzzle device in place so that it didn’t move during the process of pinning.IMG_3665IMG_3667 IMG_3669

Joe then retrieved a section of steel rod that he uses for all of the pin and weld jobs he does and cut off a small section that was long enough to fill the hole that he intended to drill. After he sized it up on the muzzle device to make sure that it was thin enough for the area we had to work with we headed over to his Bridgeport mill.IMG_3670 IMG_3673

Once the barrel was clamped in place, Joe used the control module to find the center of the muzzle device with an edge finder. Once that was all setup, Joe used an anti-walk bit to cut a dimple into the barrel so that the drill bit didn’t have a prayer of moving once he started the hole. After changing the bits out, he drilled the hole to the exact required depth to get just through the threads on the barrel without compromising the barrel wall strength. IMG_3682 IMG_3686 IMG_3692

After a quick spray in the parts, washer to remove the cutting oil and shavings the barrel was ready to take over to his welding station. The hole that Joe had drilled was nothing short of a perfect circle void of almost any tool marks. The last step before welding is to tap the small bit of rod into place to act as the pin.IMG_3696IMG_3700 IMG_3701 IMG_3746

A quick zap with his welder and the pin turned into an almost perfect dome. After we cleaned it up again and applied some cold blue to the weld the new addition to the muzzle device looked like it came from the factory that way.IMG_3760 IMG_3767 IMG_3772

After seeing how much work goes into properly pinning a muzzle device, I don’t think I will be balking at a $60 shop fee for a competent gunsmith like Joe to do the job. After all, anything under a hundred bucks is a whole lot less than it would cost me to replace the barrel when I screwed it up.

Patrick R

Patrick is a Senior Writer for The Firearm Blog and TFBTV Host. He likes guns and has liked shooting guns for as long as he can remember. You can follow Patrick on Instagram @tfbpatrick, Facebook, or contact him by email at TFBpatrick@gmail.com.

The above post is my opinion and does not reflect the views of any company or organization.


  • iksnilol

    Y’all buy bourbon by the gallon?


    • Gus Butts

      I caught that as well.

      Also, muzzle brake*.

      • Patrick R. – Staff Writer

        Autocorrect strikes again. I need to fix that.

    • JD

      If it was in a gallon jug, it sounds like it might have been some non-tax payed corn based liquor.

      • Ken

        “Corn likker”

    • Patrick R. – Staff Writer

      It wasn’t a gallon, just a large bottle. I may have embellished a touch.

      • Drew Coleman

        On the internet!? Say it ain’t so!

      • Bang Switch

        Embellished or imbibed??

        • Patrick R. – Staff Writer

          I gave up drinking years ago.

      • randomswede

        Excuse us scandinavians, we are ready to believe any tall tale of serving sizes from the US. A container of juice, soda larger than 2 liters (roughly a half US gallon) is restaurant supply wares around these parts. McDonald’s largest cup is 0.5 liters (17 fl oz).

        • 6.5x55Swedish

          Well they do have 5 liter bottles, when we buy a 2 liter bottle of soda in Sweden we feel a little bit of guilt.

        • AHill

          So a ‘Texas Micky’ (a Canadian specialty of 101 oz/ 3 liter bottle of liquor, usually comes with stand to help pouring or a little hand pump because the bottle is so massive) must sound like an impossibly tall tale to your Scandinavian ears then right?

          • randomswede

            We can lay our hands on 3 liter bottles of the “hard stuff” in taxfree stores and such, but as novelty items you’d buy for someone’s 50th birthday or the like.
            It’s not so much that it sounds impossible, it’s more that we are willing to believe them. Tell a Scandinavian that you can get a plate of fried chicken and fries the size of truck tire for $10 at “this place in texas, best I ever had” and we are more likely to nod our heads approvingly and drool than call “shinns”.

            It could simply be our awe at how Americans blatantly ignore the laws, the “Law of Jante” that is. For a better understanding of scandinavians at large I suggest a quick peek at the wikipedia article on the subject.

    • Jeff Smith

      It’s usually sold by the half gallon (1.75 liters or a “handle”), though you can occasionally find larger bottles at some stores.

      It’s the best birthday gift you can give a person. Or the worst. It could really go either way depending on the night.

      • iksnilol

        Regular quanitites to sell alcohol is 0.7 or 1 liters where I am at. I prefer liter bottles. Easier to calculate.

        • Jeff Smith

          I guess I should clarify – the most common way of getting liquor is generally the .75 liter bottle (1/5th of a gallon or “fifth”), but you can generally get a 1.75 liter bottle of whatever you want at any reputable liquor store. Liter bottles aren’t as common as .75 and 1.75 liter bottles, but they can be found.

          Granted – im only speaking from my experience – I’m in the Memphis, TN area of the US.

          • iksnilol

            I am in Norway, I find the 0.75 liter bottles to be weird. Seems like such an arbitrary quantity.

        • supergun

          You mean after you had a few?

          • iksnilol



            totally no.


      • Hinermad

        Mmm, Maker’s Mark. Got a glass sitting right here as I type.

        • Jeff Smith

          A fifth of Maker’s will grease just about any palm, especially after 10 pm (when liquor stores close in my area).

    • T Rex

      By the gallon, as I recall that’s the way Bocephus drinks his whiskey.

    • jay

      In Texas everything is larger! ;-}

      • iksnilol

        If you buy strong liquor by the gallon you have a drinking problem.

        Seriously, you can’t drink that without killing yourself. Share with a comrade or something.

        • jay

          It’s only good if shared! ;-}

      • AHill

        Then why can’t you actually get a Texas mickey IN Texas? (A peculiar 101 oz/ 3 liter bottle sold in Soviet Canuckistan liquor stores from the adequate white north)

        • jay


  • Pod

    Sadly this kind of work might mean the author’s friend will be paying an ITAR registration fee…

  • Ken

    For those who like to grind the weld flush, make sure you countersink the hole and/or make the pin sit below the top of the hole. Otherwise you just grind the weld right off. I suppose not grinding it flush makes it easier to remove later, since all you’d have to do it grind it flush and dig the pin out.

    • tazman66gt

      Wouldn’t recommend grinding it flush in the off chance there is law enforcement at the range who think it necessary to check things out. Better safe than sorry. a small ugly weld is easier than the harassment.

      • Jeff S

        Does anyone have any proof of “law enforcement” ever checking anything at any range ever? The two ranges I most often go to are just minutes from Martinsburg and I’ve never seen an ATF agent “check things out.” Are you telling me state/local cops “check things out” around the country or is this just some over embellished wive’s tale?

      • DonDrapersAcidTrip

        When in history ever has “law enforcement” investigated somebody’s 14.5 barrel at a gun range? This is a gun owner fantasy.

        This is like people obsessing over “printing” when carrying. NOBODY REALLY CARES. At least if your white that is. No cop is going to blow away your crew cut, goatee, cargo shorts and oakley wearing self away cause there’s an outline of a gun on your waistband. get real.

        • tazman66gt

          Wow, you really had to pull the race card? Sad little man.

          • DonDrapersAcidTrip

            “pull the race card” ….lmfao, when did I do that, when I made mention of the actual realities of the world? forgot you all like to just plug your ears and pretend that’s not the case.

            as much as you types are ones to cry about “political correctness” I don’t know anyone that’s a bigger cry baby about it. at some point you’re going have to learn to discuss the realities of the world for people who don’t look like you past the level of a literal 4 year old.

          • tazman66gt

            “At least if your white that is.” Making the accusation if you are black that cops WILL shoot you, hence my calling you out on pulling the race card.
            Typical liberal moron, you can’t even remember what you wrote.

          • DonDrapersAcidTrip

            No, I get that you think we exist in some vacuum where all people have equal chance of being shot, that’s what funny. And any acknowledge of reality instead of your fantasy make believe land is “pulling a race card.” I have tediously explain this all out for you apparently. If you think your boring white oakley buzzcut cargo short wearing self is just as much at risk for being shot as any random black guy you are living in an utter dream world. And it’s funny how pointing out this reality gets you angry, but sure go spend your day crying about how other people want everything to be “political correct” with no self awareness as to you rewrite your own reality to fit your biases.

          • DonDrapersAcidTrip

            also hilarious is that by your definition, people who acknowledge the world around them and that people other than themselves exist = liberals

            people blundering through life assuming their personal experiences apply to every other person on the planet = conservatives

            of course in this fevered dream world inside your head where everyone is either like you or “The Enemy” I guess I must also hate guns since it must by in defiance of the laws of physics to be pro-gun and actually apply any nuanced thought to any topic

          • Blake

            Wow you really are an ignorant ass. If you don’t want to educate yourself, fine; but don’t try to shame other gun owners into staying as ignorant as you are by acting like “liberal” is a dirty word.

            Did you not see that case a couple months ago where the black CCW owner was asked to get his drivers license, he slowly reaches for it, and the cop puts a handful of rounds into his chest? Perfect representation of how things are. Is there an argument that the suspicion is deserved? Yes, but to act like it’s not there at all is just moronic.

  • PeterK


  • Risky

    I believe silver soldering is also an acceptable method of ‘permanently attaching’ a muzzle device and requires fewer and cheaper tools. I would like to see and article on that also.

    • Patrick R. – Staff Writer

      Since that requires the barrel to be heated to the point that some feel it is detrimental to the steel I will not be the first to volunteer.

      • marathag

        Resistance Soldering.

        And to be truthful, losing that small amount strength at the end of the barrel, vs welding heat, I wouldn’t worry.

  • fuddleton

    A milling machine costs ~$4-10k depending on the setup.
    A welder costs ~$1200 for a cheap TIG machine.
    The skills to appropriately operate them have the value of an associates degree.
    The space required to safely use them requires concrete floors, ventilation, etc.
    The costs of owning a fab shop are pretty high for entry. $60 is pretty fair for a one off job.

    • supergun

      More than fair. It is not how long it takes, but what I know that takes it to get done.

  • Joshua

    $60 buys about an hour of a machinists time in his shop, and most of that hour will be spent figuring out how exactly to make what your asking for. That’s one of the reasons for the old “One piece or fifty, same price” joke. one offs take the same amount of preparation and tooling set up and development as an order for fifty parts, and usually the difference in actual cutting time is minimal. I don’t know that gunsmith you went to but I wouldn’t be surprised if one barrel cost $60 and five barrels cost $100
    probably would take him about an extra half hour to do four more barrels after the first one.

  • I don’t have a TIG welder, but I have accomplish something similar, and less noticeable, by leaving the pin a bit shorter, so when fully inserted it was shy of the surface of the muzzle device. Filled the resulting hole with my MIG welder, then milled off the resulting small mound of steel. Of course now the only way I can prove the device is permanently installed is by the fact that it can’t be removed. But, I suppose that works!

  • joshv06

    I do the Silver Solder method at home with a MAPP torch.

  • MaxPower515

    Wish my local gunsmith was this good at it. Last time they did a P&W they barely drilled through the flash hider and into the threads. I was able to wrench off the hider with minimal damage to the threads.

  • Jim_Macklin

    If hillary isn’t elected there might be a chance to get the SCOUS to revisit MILLER and actually decide the validity of the 1934 NFA. After all the Arkansas Federal Court declared the entire law to be unconstitutional and SCOUS did not decide or rule on the case. SCOUS REMANDED the case for a trial but failed to issue an injunction to stop enforcement pending final resolution of the case.
    The FDR Administration [Democrat] and the DOJ have never held that trial and have just pretended that 1934 NFA is constitutional.
    Maybe someday the stupidity of NFA and 1968 GCA will be repealed.

    • supergun

      I never understood why they outlawed the suppressors. Many people have them. Most don’t. It sure would help out on the noise level and hearing losses. You would think they care so much about our hearing, but I guess the money they get overrides any caring they have for us. The automatic laws are just as perplexing. Most people would not be able to hit the side of a barn in automatic fire. The shooters are more accurate in semi-auto fire. Makes no sense. But I guess the money they receive overrides any common sense. The very people they don’t want to have suppressors or automatics will have them anyway,,,,you know,,,,the ones who care nothing about those laws.

  • Bob

    years ago, I had to have a flash suppressor WELDED onto my barrel on my FN/FAL kit/parts gun with 10 compliant US made parts!!
    First the atf wanted it pinned.
    then they wanted it welded in 3 EQUALLY spaced places
    then they wanted it welded in 4 EQUALLY spaced places!
    so now, after you did three. it won’t be welded EQUALLY when you do FOUR!!
    SO……………what to do….???
    Weld a BEAD all the way around the da*ned thing.
    Later, I bought a newer barrel that complied with whatever rules were in place at that date since the “ban” had sunsetted in 2004, and I had it done by a PRO who built FALS for a living!!