Pin and welded barrels

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  • firemn260

    Active Member
    Sep 15, 2015
    354
    Harford County
    Been a little bit since I have posted so I thought I would share something that has had me thinking lately.

    A friend of mine moved to PA about 5 or so years ago but we still try to keep in touch. Well the other day we were catching up and he was telling me about his most recent AR he put together. He had bought a upper at a swap meet that has a 14.7” barrel with a pinned and welded A2 fh on it. My friend is not new to the AR/m4 platform, so he said the weld job looked legit and couldn’t pass up the good deal on the upper. So he brought it home and put it together with a lower he had built for his wife. For the next year and half they took it out for regular range sessions.

    Fast forward to a few months ago my friend finally got to pick up his first can out of nfa jail. So wanting to change the muzzle device to a quick mount for the can, he takes the upper to a local gunsmith to have the work done. This is where it gets interesting. A few days later he gets a call from the gunsmith stating the the pin and weld job on his barrel was not properly done. Apparently who ever did the work had drilled the FH just enough to add a bead of weld, that we are guessing would give the appearance of being pinned. It also had rockset in it. So my buddy has essentially been in possession of a unregistered short barrel rifle for a year and a half and didn’t know it. Luckily he just took the upper to the gunsmith and not the whole weapon.

    The only conclusion we can come to is whoever put the upper together wanted to be able to remove the flash hider without drilling and it still appear to be legal. He is regretful about trusting someone’s word about such a touchy and legal subject but I had to admit I more than likely would of got fooled by it too.

    So this whole incident got me thinking. Who would actually break out a wrench and test if it’s been done right? I have done two pin and weld jobs on my own builds with trustworthy advice from a gunsmith who has done many of them. Never would I be in a situation where this issue would come in question but it makes me wonder if there are people out there who have had there barrels wrenched on to make sure there is actually a pin in it.
    I know I’m probably way over thinking this and I have been hesitant to bring this up on a open forum, because to be honest it is a crafty way to deceive the unsuspecting eye on this matter.
    Just wondering what your guys thoughts on this are seeing the whole non nfa sub 16” barrel thing has been getting pretty popular.
     

    alucard0822

    For great Justice
    Oct 29, 2007
    17,703
    PA
    Unless it's a factory pinned barrel, or done by a reputable gunsmith, i would pass. Probably near 0 chance of anything coming out of it for otherwise law-abiding citizens, but if somehow it ended up getting checked out by the ATF, you could be boned. They are kind of a PITA to deal with though, lightweight 16"s with minimalist muzzle devices, or barrels short enough to actually be beneficial on braced "pistols" are currently a much better option, 14.5s just aren't worth the hassle to pin, brace or get a $200 stamp IMO.
     

    jrumann59

    DILLIGAF
    MDS Supporter
    Feb 17, 2011
    14,024
    Unless it's a factory pinned barrel, or done by a reputable gunsmith, i would pass. Probably near 0 chance of anything coming out of it for otherwise law-abiding citizens, but if somehow it ended up getting checked out by the ATF, you could be boned. They are kind of a PITA to deal with though, lightweight 16"s with minimalist muzzle devices, or barrels short enough to actually be beneficial on braced "pistols" are currently a much better option, 14.5s just aren't worth the hassle to pin, brace or get a $200 stamp IMO.
    I had 12.7" pinned and welded. I had 4" muzzle device but I had Lord Chad perform the deed and he donated blood to the muzzle device to make it "holy".
     

    jrumann59

    DILLIGAF
    MDS Supporter
    Feb 17, 2011
    14,024
    Has anyone ever been convicted of having an unregistered SBR whose FH was only pinned "a little bit"? Is there an ATF memo somewhere on the proper pin depth?

    I think it was quoted before but I think it requires enough depth that the muzzle device cannot be removed by normal means that will not damage the barrel.
     

    alucard0822

    For great Justice
    Oct 29, 2007
    17,703
    PA
    Has anyone ever been convicted of having an unregistered SBR whose FH was only pinned "a little bit"? Is there an ATF memo somewhere on the proper pin depth?

    2.1.3 rifle, 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.

    Not sure on a torque spec that must be exceeded or how much "damage" has to occur to the barrel when attempting to remove it, but most I have seen drill past the muzzle device about 1/8" into the barrel, use a peice of welding rod, and just a little bead of weld over it. To remove it, grinding the weld off, 1/2 way through the muzzle device, then rocking the muzzle device usually allows the pin to fall out.
     

    danb

    dont be a dumbass
    Feb 24, 2013
    22,704
    google is your friend, I am not.
    Not sure on a torque spec that must be exceeded or how much "damage" has to occur to the barrel when attempting to remove it, but most I have seen drill past the muzzle device about 1/8" into the barrel, use a peice of welding rod, and just a little bead of weld over it. To remove it, grinding the weld off, 1/2 way through the muzzle device, then rocking the muzzle device usually allows the pin to fall out.

    But what is the actual minimum standard for "blind pinning". I dont think "damage" is the standard. I think removal with tools is the standard.
     

    davsco

    Ultimate Member
    Oct 21, 2010
    8,624
    Loudoun, VA
    the funny thing is i've been reading threads where folks screwed their brakes on, temporarily, with no loctite, pin&weld, rocksett or the like, and they galled or whatever and they couldn't get them off...
     

    firemn260

    Active Member
    Sep 15, 2015
    354
    Harford County
    I totally agree but to be honest I probably would of went for the same deal without thinking twice if there was actually a pin in it. I have a different view now. I’m sure My buddy regrets that but had he not wanted to change the fh nobody would of ever been the wiser.

    The only reason I did two of them was I was impatient waiting for arp to get 16” barrels back in stock for my 6.8 build and got the 14.7 they had. The other was a m4 barrel I got from a ex military armorer that I used in a cheap Frankenstein build I threw together.
    I used a piece of drill bit for both and made sure I drilled to the bottom of the thread. Even if you did break it loose you would have to overcome the threads all the way out. The first I did with a mig but the second I did with a tig torch. I left about a 1/16 of the pin sticking out and zapped it with just the torch. Looks a lot cleaner but would be more of a pia if I had to drill it out.
     

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