Pin and Welding spacer

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  • jrumann59

    DILLIGAF
    MDS Supporter
    Feb 17, 2011
    14,024
    I wonder of the legality of a machined spacer to would go around the outside of threaded section of a muzzle device for pin and welding, the purpose would be to destroy that spacer instead of the muzzle device if you ever need to remove it. So in essence you have the steel collar machined to match the flats on the muzzle device, drill through both for pinning and weld the pin to the outer spacer. Just a thought.
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    I can't envision what you are saying.

    The pin has to go through the muzzle device and the barrel to prevent removal.

    If you mean to just put the weld on that outer collar, I am not sure BATF would agree. Remember, the whole point is to make it almost impossible to remove.
     

    Biggfoot44

    Ultimate Member
    Aug 2, 2009
    32,881
    If I'm visualizing correctly ..... Never mind , I read one more time , and still at a loss .
     

    camo556

    Ultimate Member
    Aug 29, 2021
    2,634
    wut?

    The point of pinning and welding a muzzle device is to ensure compliance with AFT and OAL. So the spacer is welded to the barrel, and the muzzle device to the spacer? Is this your vision? So you pay a whole bunch of money for a spacer to be machined, just so you save a few bucks on a muzzle device?
     

    Biggfoot44

    Ultimate Member
    Aug 2, 2009
    32,881
    I could see the OP wanting to be able to change screw on muzzle devices .

    I don't know if this is what OP had in mind , but I did brainstorm something that hits many of his checkmarks :

    Existing bbl has outer threads of usual specs.

    Mystery adapter has internal threads to corespond to bbl threads . Back end of mystery device to eventually be P&W to bbl .

    The mystery device is of such length itself , that when pinned to bbl , it will provide the necessary length by itself .

    Mystery device has I.D. of bore diameter plus necessary and prudent clearance .

    Front of mystery device has external threads of * A * standard for muzzle devices , which can be frequently swapped w/o ever having length issues .

    Being cognizant of the larger than bore I.D. of device and necessary metal thickness to the bottom of the threads , the front threads might have to be different from rear threads . ie , bbl threads and rear device threads might be 1/2 x 20 , but front of device and actual muzzle device(s) might have to be 5/8 x whatever .

    I won't speculate if this whole thing is Worthwhile , but I think the hypothetical above is internally consistent .
     

    Rambler

    Doing the best with the worst.
    Oct 22, 2011
    2,162
    I think I understand what you are asking. Correct me if I am wrong. You want a collar or sleeve which goes over the muzzle device in the area of the threads. They are pinned to each other (and the barrel too since otherwise it could still be unscrewed) and the pin is welded to the collar.

    I do not know the legality of it. But the custom machine work to make the collar would likely cancel the saving of the muzzle device.
     

    Biggfoot44

    Ultimate Member
    Aug 2, 2009
    32,881
    As I visualize what Rambler outlines , it would be problematic to actually do , And totally pointless .
     

    Johnny5k

    Ultimate Member
    Nov 24, 2020
    1,021
    I think I understand what you are asking. Correct me if I am wrong. You want a collar or sleeve which goes over the muzzle device in the area of the threads. They are pinned to each other (and the barrel too since otherwise it could still be unscrewed) and the pin is welded to the collar.

    I do not know the legality of it. But the custom machine work to make the collar would likely cancel the saving of the muzzle device.

    I think you got what he is saying. I agree. Probably cheaper to pay the machinist to machine off the welds and remove the pin, and repair any damage to the MD.
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,815
    I can't envision what you are saying.

    The pin has to go through the muzzle device and the barrel to prevent removal.

    If you mean to just put the weld on that outer collar, I am not sure BATF would agree. Remember, the whole point is to make it almost impossible to remove.

    If I'm visualizing correctly ..... Never mind , I read one more time , and still at a loss .

    wut?

    The point of pinning and welding a muzzle device is to ensure compliance with AFT and OAL. So the spacer is welded to the barrel, and the muzzle device to the spacer? Is this your vision? So you pay a whole bunch of money for a spacer to be machined, just so you save a few bucks on a muzzle device?

    As I visualize what Rambler outlines , it would be problematic to actually do , And totally pointless .

    So mebbe I'm not as dumb as I look. Mebbe.

    It seems to be a long way around the barn?
     

    alucard0822

    For great Justice
    Oct 29, 2007
    17,643
    PA
    Good idea, and should work per the letter of the law

    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.

    basically think of a flash hider of sufficient length, install it, slip a steel ring around the base, drill a hole through the spacer, muzzle device and into the barrel. Then drop in a pin holding all 3 together and weld over the head of the pin through the outer spacer ring, giving you the correct blind pin with head welded over. To remove, just cut the outer spacer or drill through the weld and pull the pin out, remove it, and you have an intact muzzle device, to remove to replace a gas block or handguard etc. Then reassemble with a new cheap disposable and sacrificial outer ring that the head of the pin will be welded to. There is nothing in the law or regs against a 2 piece muzzle device, essentially that is what it would be. Might go for a letter for it, seems kosher, doubt you would get prosecuted, but only 1 way to be reasonably sure, at least till they change their mind. This is an idea you could probably patent, basically just manufacture a few short sections of melonited tube about 5/8 ID with a drilled pilot hole, could even include a bit with a stop collar to make it easy to install/remove.

    basically this, want to take off the muzzle device, cut the outer collar. meets the "blind pinning with head welded over" ATF requirement for permanent attachment.
    20211201_101304.jpg


    conventional pin/weld, need to grind or drill the weld/pin out of it, and needs to be replaced if it is removed.
    20211201_101316.jpg
     

    jrumann59

    DILLIGAF
    MDS Supporter
    Feb 17, 2011
    14,024
    I think I understand what you are asking. Correct me if I am wrong. You want a collar or sleeve which goes over the muzzle device in the area of the threads. They are pinned to each other (and the barrel too since otherwise it could still be unscrewed) and the pin is welded to the collar.

    I do not know the legality of it. But the custom machine work to make the collar would likely cancel the saving of the muzzle device.

    That is exactly what I am envisioning.
     

    jrumann59

    DILLIGAF
    MDS Supporter
    Feb 17, 2011
    14,024
    Good idea, and should work per the letter of the law



    basically think of a flash hider of sufficient length, install it, slip a steel ring around the base, drill a hole through the spacer, muzzle device and into the barrel. Then drop in a pin holding all 3 together and weld over the head of the pin through the outer spacer ring, giving you the correct blind pin with head welded over. To remove, just cut the outer spacer or drill through the weld and pull the pin out, remove it, and you have an intact muzzle device, to remove to replace a gas block or handguard etc. Then reassemble with a new cheap disposable and sacrificial outer ring that the head of the pin will be welded to. There is nothing in the law or regs against a 2 piece muzzle device, essentially that is what it would be. Might go for a letter for it, seems kosher, doubt you would get prosecuted, but only 1 way to be reasonably sure, at least till they change their mind. This is an idea you could probably patent, basically just manufacture a few short sections of melonited tube about 5/8 ID with a drilled pilot hole, could even include a bit with a stop collar to make it easy to install/remove.

    basically this, want to take off the muzzle device, cut the outer collar. meets the "blind pinning with head welded over" ATF requirement for permanent attachment.
    View attachment 328418


    conventional pin/weld, need to grind or drill the weld/pin out of it, and needs to be replaced if it is removed.
    View attachment 328419


    Exactly i was trying to explain. Maybe a little smaller but overall proof of concept is what I was trying to describe.
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    I think I understand what you are asking. Correct me if I am wrong. You want a collar or sleeve which goes over the muzzle device in the area of the threads. They are pinned to each other (and the barrel too since otherwise it could still be unscrewed) and the pin is welded to the collar.

    I do not know the legality of it. But the custom machine work to make the collar would likely cancel the saving of the muzzle device.

    As I visualize what Rambler outlines , it would be problematic to actually do , And totally pointless .

    This is what I finally puzzled out.

    I think his idea is that you could grind on the collar, remove the pin, and not have any marks (other than the hole for the pin) in the muzzle device.
     

    Biggfoot44

    Ultimate Member
    Aug 2, 2009
    32,881
    It finally clicked from Alucard's post with pics .

    Added - OP threw me off with machining inside of mystery device to match the flats on muzzle device , rather than the cylindrical implied by Alucard .
     

    RRomig

    Ultimate Member
    Industry Partner
    MDS Supporter
    Aug 30, 2021
    1,924
    Burtonsville MD
    I’m pretty sure I get what your saying but I think it’s way more work than needed. A good tig weld can be very unobtrusive and very little work to grind smooth and punch out the pin when you want to change to something else. The weld would have very little penetration but be plenty strong. There will be a very small low spot at the site of the work but certainly nothing to be concerned about. The muzzle device shouldn’t be ruined. I’ve actually never thought the work to save 1 1/2” off a barrel was worth it but many people do so I get it. Good luck.

    I did want to add it is a creative idea for someone that absolutely doesn’t want to mark the muzzle device.
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,815
    I've removed P&W muzzle devices by simply drilling out the pin. It is only welded to the device, not the threads. I have reused said muzzle brakes on other guns. I still don't get it... :shrug:
     

    jrumann59

    DILLIGAF
    MDS Supporter
    Feb 17, 2011
    14,024
    I've removed P&W muzzle devices by simply drilling out the pin. It is only welded to the device, not the threads. I have reused said muzzle brakes on other guns. I still don't get it... :shrug:

    It would some peace of mind, there have been posts where a muzzle device had to be pretty much destroyed due to crappy weld where a bit walks, or weld jobs where it can't be located. I have a device Chad pinned and welded and I can barely perceive the weld:innocent0
     

    Cwarnick

    Member
    Oct 16, 2020
    26
    perspective

    i would say this would be a waste of time.

    say you pin the MD and sleeve, then you need to remove...

    you then grind off the weld, pull the pin and remove the MD and sleeve.

    you now have a hole thru the barrel and muzzle device that might shift upon removal and retorquing properly...

    and if you want to use a different muzzle device, you already have a hole through your barrel threads weakening the connection for yet another hole...

    you could potentially re-drill a new barrel using the same MD as a drill bushing, but thats as far as ide take it...


    if your not running a threaded external adapter, why not consider a muzzle device the same diameter as your gas journal, that way no removal is required for dissassembly...

    or just pick something and be content with it.

    If its a bigger diameter, than you lose your gas block and barrel nut to your barrel without having to remove the weld...

    i feel like this is creating a solution to a problem no one has... as a weld should only barely cover the pin head enough to attach it at all.

    and dont grind it down smooth after welding, leave the little bead there so you can see it.

    20201204_154307-scaled.jpg
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,815
    It would some peace of mind, there have been posts where a muzzle device had to be pretty much destroyed due to crappy weld where a bit walks, or weld jobs where it can't be located. I have a device Chad pinned and welded and I can barely perceive the weld:innocent0

    This brake was put on a 14.5" barrel which I no longer needed, but for $125, I was throwing the Surefire QD mount away. Now it sits atop a 16" RRA barrel. It took 2 tries to get directly onto the pin, but I'm not concerned with beauty in this case. If I was, I could just reweld over the hole.
     

    Attachments

    • pin2.jpg
      pin2.jpg
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    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,815
    Good idea, and should work per the letter of the law



    basically think of a flash hider of sufficient length, install it, slip a steel ring around the base, drill a hole through the spacer, muzzle device and into the barrel. Then drop in a pin holding all 3 together and weld over the head of the pin through the outer spacer ring, giving you the correct blind pin with head welded over. To remove, just cut the outer spacer or drill through the weld and pull the pin out, remove it, and you have an intact muzzle device, to remove to replace a gas block or handguard etc. Then reassemble with a new cheap disposable and sacrificial outer ring that the head of the pin will be welded to. There is nothing in the law or regs against a 2 piece muzzle device, essentially that is what it would be. Might go for a letter for it, seems kosher, doubt you would get prosecuted, but only 1 way to be reasonably sure, at least till they change their mind. This is an idea you could probably patent, basically just manufacture a few short sections of melonited tube about 5/8 ID with a drilled pilot hole, could even include a bit with a stop collar to make it easy to install/remove.

    basically this, want to take off the muzzle device, cut the outer collar. meets the "blind pinning with head welded over" ATF requirement for permanent attachment.
    View attachment 328418


    conventional pin/weld, need to grind or drill the weld/pin out of it, and needs to be replaced if it is removed.
    View attachment 328419

    I'm a little conflicted seeing a P&W over top of a crush washer. I would have shimmed it.
     

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