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Thread: DPMS barrel extension and washer

  1. #1
    Boolit Mold 10mm Witness's Avatar
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    DPMS barrel extension and washer

    Do I need to have a washer between the barrel and the barrel extension? Yep its dumb question yo some people but not to knuckle head like me.
    Jim Ceglinski
    Southfield, Mi. 48075

  2. #2
    Boolit Master


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    Interesting question! I have never removed the extension.

  3. #3
    Boolit Grand Master


    stubshaft's Avatar
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    Normally you would use the "washer" or shims to clock the handguard and help it line up while tightening it to the correct torque value. In answer to your question, maybe not. I have built a few uppers that they (shims) were not needed.
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  4. #4
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    My understanding is there is no washer. The extension is torqued to the barrel and then the gas port and alignment pin are drilled to top dead center.

    It would be difficult to replace a barrel extension and have the gas port and alignment pin in proper orientation.
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  5. #5
    Boolit Master elmacgyver0's Avatar
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    Most barrel extensions come already on the barrel, for ARs anyway.

  6. #6
    Boolit Buddy gumbo333's Avatar
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    What is the torque value for a barrel extension. If you had the tools and talent to install a barrel extension drilling a gas port would like be pretty simple. But why?
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  7. #7
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    Quote Originally Posted by 10mm Witness View Post
    Do I need to have a washer between the barrel and the barrel extension? Yep its dumb question yo some people but not to knuckle head like me.
    No, a washer or shim will change your headspace and indexing and should normally never be used or needed. Could out of spec assemblies be fixed using a shim? Yes, but that is for out of spec assemblies.

    They do make shims that go between the barrel extension and the upper receiver.
    Last edited by M-Tecs; 01-07-2023 at 02:02 AM.
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  8. #8
    Boolit Grand Master



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    Quote Originally Posted by gumbo333 View Post
    What is the torque value for a barrel extension. If you had the tools and talent to install a barrel extension drilling a gas port would like be pretty simple. But why?
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    2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."

    "Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
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  9. #9
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    A barrel nut is very different from an extension. The AR15 extension is torqued to 150 foot pounds.
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  10. #10
    Boolit Grand Master



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    Quote Originally Posted by imashooter2 View Post
    A barrel nut is very different from an extension. The AR15 extension is torqued to 150 foot pounds.
    You are correct. I am multitasking today (not very well) with a septic pump issues and snow removal issues. I posted specs for the barrel nut not the extension. Thanks for posting the correct specs.
    2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."

    "Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
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  11. #11
    Boolit Grand Master popper's Avatar
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    Shims are used to clock the gas tube to the nut hole. Most new barrel nuts don't have the notches/holes so shims not needed.
    Whatever!

  12. #12
    Boolit Mold 10mm Witness's Avatar
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    I am speaking about the extension not the barrel nut. They are 2 different parts doing different jobs.
    Jim Ceglinski
    Southfield, Mi. 48075

  13. #13
    Boolit Grand Master popper's Avatar
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    Shouldn't be any shims for extension unless somebody screwed up. No reason for any!! The alignment pin is for the feed ramp alignment - the barrel itself has NO alignment. If installing a barrel into an extension that has the hole pre-drilled, the pin has NO reason to go into the barrel.
    Whatever!

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check