Results 1 to 17 of 17

Thread: Cut long M4 Colt AR15 barrel to short barrel

  1. #1
    Join Date
    Feb 2010
    Posts
    15
    Feedback Score
    0

    Cut long M4 Colt AR15 barrel to short barrel

    Wondering if it would be feasible to cutdown a 16 inch M4 Colt barrel down to 12.5 inches? I was reading all of the threads referencing short NFA rifles and decided it was time to do something with my blank upper receiver.
    I would like to do a short barrel upper receiver project; a 10.5 and 11.5 inch barrel maybe too small for my taste. I like the idea of having the short barrel but also want the advantage of velocity, energy, and distance. I am looking for CQB, active shooter scenarios, and if I need to take out something up to 200-350 yds. ( I have other rifles that can reach out to 800 yds. if I needed them )
    The short 12.5 barrel makes sense. I know Colt doesn't make a 12.5 inch barrel; hence taking the long barrel and reducing it down. I would like to stick to Colt barrel as I have a registered Colt NFA lower receiver and my blank upper receiver is Colt M4. I would rather not mix and match manufacturers. ( Sorry guys...one stop shopping!) Does anyone know who can do the barrel reduction? Any opinions and advise is appreciated.

  2. #2
    Join Date
    Jan 2008
    Location
    AZ-Waging jihad against crappy AR's.
    Posts
    20,036
    Feedback Score
    80 (100%)
    My advice is not to cut the Colt barrel. But, I sense that you will do it anyways. I would buy a Bravo Company 11.5" barrel and rebarrel your upper. You can offset the cost by selling your 6920 barrel assuming it is in proper shape and condition.

    I have a BCM 11.5" that I built and it runs like a champ. Anyone who has seen it will attest to that.

    Quote Originally Posted by Repr762 View Post
    Wondering if it would be feasible to cutdown a 16 inch M4 Colt barrel down to 12.5 inches? I was reading all of the threads referencing short NFA rifles and decided it was time to do something with my blank upper receiver.
    I would like to do a short barrel upper receiver project; a 10.5 and 11.5 inch barrel maybe too small for my taste. I like the idea of having the short barrel but also want the advantage of velocity, energy, and distance. I am looking for CQB, active shooter scenarios, and if I need to take out something up to 200-350 yds. ( I have other rifles that can reach out to 800 yds. if I needed them )
    The short 12.5 barrel makes sense. I know Colt doesn't make a 12.5 inch barrel; hence taking the long barrel and reducing it down. I would like to stick to Colt barrel as I have a registered Colt NFA lower receiver and my blank upper receiver is Colt M4. I would rather not mix and match manufacturers. ( Sorry guys...one stop shopping!) Does anyone know who can do the barrel reduction? Any opinions and advise is appreciated.





    "A firearm should be considered a fighting weapon first. Any other use should be considered a bonus." -Me

    Click here for Semper Paratus Arms AR15 armorer schedule/locations.

    M4C Misc. Training and Course Announcements- http://www.m4carbine.net/forumdisplay.php?f=141

    Multiple armorer certifications

    I am affiliated and work with SIONICS Weapon Systems in Tucson, AZ

  3. #3
    Join Date
    Jun 2008
    Posts
    269
    Feedback Score
    1 (100%)
    I've done it. The threads will start just ahead of the M203 notch. While cost is higher, one advantage is that you know you will have perfect threads if you plan on mounting a suppressor.

    I don't have a picture of the bare barrel because my I have a reflex suppressor, but since everybody loves pictures...


  4. #4
    Join Date
    Oct 2009
    Posts
    1,440
    Feedback Score
    12 (100%)
    Quote Originally Posted by Repr762 View Post
    Wondering if it would be feasible to cutdown a 16 inch M4 Colt barrel down to 12.5 inches? I was reading all of the threads referencing short NFA rifles and decided it was time to do something with my blank upper receiver.
    I would like to do a short barrel upper receiver project; a 10.5 and 11.5 inch barrel maybe too small for my taste. I like the idea of having the short barrel but also want the advantage of velocity, energy, and distance. I am looking for CQB, active shooter scenarios, and if I need to take out something up to 200-350 yds. ( I have other rifles that can reach out to 800 yds. if I needed them )
    The short 12.5 barrel makes sense. I know Colt doesn't make a 12.5 inch barrel; hence taking the long barrel and reducing it down. I would like to stick to Colt barrel as I have a registered Colt NFA lower receiver and my blank upper receiver is Colt M4. I would rather not mix and match manufacturers. ( Sorry guys...one stop shopping!) Does anyone know who can do the barrel reduction? Any opinions and advise is appreciated.
    Nobody better than SAW to machine your Colt barrel down and make the proper gas port modifications. They aren't cheap but it will get done right including re-parking your barrel assembly. You will get it back looking better than new.
    Last edited by MarkG; 02-26-11 at 23:28. Reason: Syntax

  5. #5
    Join Date
    Jan 2008
    Location
    AZ-Waging jihad against crappy AR's.
    Posts
    20,036
    Feedback Score
    80 (100%)
    That's true. I just hate seeing someone cut down a barrel for no reason when there are other options.

    Quote Originally Posted by MK18Pilot View Post
    Nobody better than SAW to machine your Colt barrel down and make the proper gas port modifications. They aren't cheap but it will get done right including re-parking your barrel assembly. You will get it back looking better than new.





    "A firearm should be considered a fighting weapon first. Any other use should be considered a bonus." -Me

    Click here for Semper Paratus Arms AR15 armorer schedule/locations.

    M4C Misc. Training and Course Announcements- http://www.m4carbine.net/forumdisplay.php?f=141

    Multiple armorer certifications

    I am affiliated and work with SIONICS Weapon Systems in Tucson, AZ

  6. #6
    Join Date
    Dec 2008
    Location
    Decatur, IN
    Posts
    1,532
    Feedback Score
    68 (96%)
    The only AR barrel I have ever had cut down was an old Bushmaster 16in carbine barrel that I had no other use for. My SBR is registered as 10.5 but Ive been running a 12.5 on it for a while.

    Cut the Bushy 16in down to 10.5 and opened the gas port and put it on the original upper it came on with the pinned A2 front sight gas block assembly it came with as well and slapped a MOE handguard. Now I have a 10.5 available if necessary.

    I wouldn't cut a Colt barrel down. Just spend the $230 and get a BCM 12.5 BCM barrel.
    Be without fear in the face of your enemies.
    Be brave and upright that God may love thee.
    Speak the truth always, even if it leads to your death.
    Safe guard the helpless and do no wrong.


    In the end, as you fade into the night, who will tell, the story of your life?
    ---------------
    JF Arms Company - Owner
    HSS 2Gun Series - MD @ Hillside Shooting Sports

  7. #7
    Join Date
    Feb 2010
    Posts
    15
    Feedback Score
    0
    Thanks for the info guys. Like I mentioned before, I have a blank upper receiver and registered lower. I don't have the barrel yet but will consider all of your advise before proceeding.

  8. #8
    Join Date
    Sep 2007
    Location
    AZ
    Posts
    21,402
    Feedback Score
    8 (100%)
    Quote Originally Posted by jwfuhrman View Post
    I wouldn't cut a Colt barrel down. Just spend the $230 and get a BCM 12.5 BCM barrel.
    I tend to agree.... I hate to see a ****tard hack on a Colt Barrel.

    But to me.... a 16" barrel with a carbine gas system is as useless as tits on a lightening bolt.

  9. #9
    Join Date
    Dec 2008
    Location
    Decatur, IN
    Posts
    1,532
    Feedback Score
    68 (96%)
    Quote Originally Posted by markm View Post
    But to me.... a 16" barrel with a carbine gas system is as useless as tits on a lightening bolt.
    LMAO, I literally laughed so hard I just broke my chair
    Be without fear in the face of your enemies.
    Be brave and upright that God may love thee.
    Speak the truth always, even if it leads to your death.
    Safe guard the helpless and do no wrong.


    In the end, as you fade into the night, who will tell, the story of your life?
    ---------------
    JF Arms Company - Owner
    HSS 2Gun Series - MD @ Hillside Shooting Sports

  10. #10
    Join Date
    Jun 2007
    Location
    The Free State of Nebraska
    Posts
    4,248
    Feedback Score
    6 (100%)
    Quote Originally Posted by beavo451 View Post
    I've done it. The threads will start just ahead of the M203 notch. While cost is higher, one advantage is that you know you will have perfect threads if you plan on mounting a suppressor.


    Bullshit.

    What proof do you have that threads will be concentric to the bore after a 3rd party aftermarket job over a high end factory job done on factory fixturing that is centered on the bore rather than the OD surface of the barrel?

    The OP needs to replace the barrel with another barrel made at the factory to his desired length.

    He can sell off the 6920 barrel and get a DD 12.5" and will maintain factory originality. It is also easier to do if you have the right tools.
    Last edited by scottryan; 03-01-11 at 09:10.
    "Not every thing on Earth requires an aftermarket upgrade." demigod/markm

  11. #11
    Join Date
    Jan 2011
    Location
    Oregon
    Posts
    9
    Feedback Score
    0

    Wink

    error
    Last edited by west9883; 03-02-11 at 01:48. Reason: nevermind

  12. #12
    Join Date
    Jun 2006
    Posts
    1,734
    Feedback Score
    7 (100%)
    Quote Originally Posted by scottryan View Post
    Bullshit.

    What proof do you have that threads will be concentric to the bore after a 3rd party aftermarket job over a high end factory job done on factory fixturing that is centered on the bore rather than the OD surface of the barrel?

    The OP needs to replace the barrel with another barrel made at the factory to his desired length.

    He can sell off the 6920 barrel and get a DD 12.5" and will maintain factory originality. It is also easier to do if you have the right tools.
    The people that do my AR work don't pay dues to the UAW. But their work is perfect.

  13. #13
    Join Date
    Jun 2006
    Posts
    592
    Feedback Score
    0
    Quote Originally Posted by scottryan View Post
    Bullshit.

    What proof do you have that threads will be concentric to the bore after a 3rd party aftermarket job over a high end factory job done on factory fixturing that is centered on the bore rather than the OD surface of the barrel?

    The OP needs to replace the barrel with another barrel made at the factory to his desired length.

    He can sell off the 6920 barrel and get a DD 12.5" and will maintain factory originality. It is also easier to do if you have the right tools.
    The OP doesn't "need" to do anything other than what he wants to do.

    There's a lot of guys that do quality barrel work, including chopping and threading them.
    Last edited by S-1; 03-02-11 at 01:59.

  14. #14
    Join Date
    Jun 2007
    Location
    The Free State of Nebraska
    Posts
    4,248
    Feedback Score
    6 (100%)
    Quote Originally Posted by S-1 View Post
    The OP doesn't "need" to do anything other than what he wants to do.

    There's a lot of guys that do quality barrel work, including chopping and threading them.

    He is the one that came on here asking what to do.
    "Not every thing on Earth requires an aftermarket upgrade." demigod/markm

  15. #15
    Join Date
    May 2007
    Location
    God's Country
    Posts
    984
    Feedback Score
    5 (100%)
    Quote Originally Posted by Iraqgunz View Post
    That's true. I just hate seeing someone cut down a barrel for no reason when there are other options.
    16" M4 barrels are already "wrong", and 6920s are cheap enough now that they make great SBRs. I cant see buying one without replacing or chopping the barrel.

  16. #16
    Join Date
    May 2007
    Location
    God's Country
    Posts
    984
    Feedback Score
    5 (100%)
    Quote Originally Posted by scottryan View Post
    Bullshit.

    What proof do you have that threads will be concentric to the bore after a 3rd party aftermarket job over a high end factory job done on factory fixturing that is centered on the bore rather than the OD surface of the barrel?
    Most places like ADCO do that already, Ill take threads cut by a guy running a machine over a mass producing factory job anyday.

  17. #17
    Join Date
    Oct 2009
    Location
    sc
    Posts
    82
    Feedback Score
    0
    Quote Originally Posted by N.Franklin View Post
    Most places like ADCO do that already, Ill take threads cut by a guy running a machine over a mass producing factory job anyday.
    Same here. They did good work on one of my barrels.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •