Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 21

Thread: Broken Colt bolt, and what to look for...

  1. #11
    Dano5326 Guest
    A solid armorer can use x-ray to check for the initial hairline cracks in bolts. Often seen between 7 & 14K rds depending on firing schedule.

    BTW I have only seen Colt bolts shear lugs before. However, plenty of DPMS & BM bolt snap at cam pin. Was this in a Colt carrier?

  2. #12
    Join Date
    Jul 2007
    Location
    SC
    Posts
    1,367
    Feedback Score
    9 (100%)
    Quote Originally Posted by Dano5326 View Post
    A solid armorer can use x-ray to check for the initial hairline cracks in bolts. Often seen between 7 & 14K rds depending on firing schedule.

    BTW I have only seen Colt bolts shear lugs before. However, plenty of DPMS & BM bolt snap at cam pin. Was this in a Colt carrier?
    Yes Sir, Colt factory 6933. The only changes to this rifle are a Knight's Midlength URX, Colt H3 buffer from SAW and a SAW or BCM extractor spring upgrade w/o ring.

    Like I said before, this rifle has never skipped a beat and was still running fine when the crack was found. How long it would have continued to run is unknown.

  3. #13
    Join Date
    Sep 2007
    Location
    AZ
    Posts
    27,217
    Feedback Score
    14 (100%)
    You should shoot it to destruction. Maybe drop it in at the range and see how many more rounds it'll take.

  4. #14
    Join Date
    Jan 2008
    Location
    AZ-Waging jihad against crappy AR's.
    Posts
    24,902
    Feedback Score
    104 (100%)
    Something else to consider. IIRC shooting suppressed will also accelerate wear (unless I am wrong) due to the excess backpressure that is created.



    Owner/Instructor at Semper Paratus Arms

    Facebook: https://www.facebook.com/SemperParatusArms/

    Semper Paratus Arms AR15 Armorer Course http://www.semperparatusarms.com/cou...-registration/

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

    Master Armorer/R&D at SIONICS Weapon Systems- http://sionicsweaponsystems.com

  5. #15
    Join Date
    Jun 2006
    Posts
    1,760
    Feedback Score
    7 (100%)
    As Dano noted this sort of failure is rare in Colts. Pat Rogers told us in 2005 that he has never seen a Colt fail at the cam pin hole, only pictures.

  6. #16
    Join Date
    Jul 2007
    Location
    SC
    Posts
    1,367
    Feedback Score
    9 (100%)
    I completely agree that running a can accelorates parts wear. I think I'm gonna do what Markm suggested and put it back in the rifle and run it until failure. Take it out every few hundred rounds (if it last that long) and measure the progress of the crack. I'd like to get some good magnified photos of the crack as it is now before I start though. I will report back.
    I also noticed a fair amount of throat wear using a small borescope at work. Once it breaks, I'm gonna pull the barrel and cut it in half length wise to get some good pictures of the throat and gas port wear patterns. It needs some 11.5" BCM hammerforged goodness anyways.

  7. #17
    Join Date
    Feb 2007
    Location
    Minneasota
    Posts
    81
    Feedback Score
    0
    Thanks Hootiewho for running the bolt till it fails. I'm looking forward to the report.

  8. #18
    Join Date
    Sep 2007
    Location
    AZ
    Posts
    27,217
    Feedback Score
    14 (100%)
    Man! Don't cut that barrel if it still headspaces good!!

    I have a Colt 11.5 commando with nasty throat erosion. But it still head spaces good and shoots very good groups.

  9. #19
    Join Date
    Jul 2007
    Location
    SC
    Posts
    1,367
    Feedback Score
    9 (100%)
    I mainly want to do it for another reason. I have been doing some testing on some AR rifles comparing them to the Scar using some specialized test equipment. This equipment allows me to look at every event of the firing cycle, comparing the two systems, and comparing different ARs to each other. I have a 6933 that has hardly been fired and I want to compare the firing cycle of one in new condition to another well used. I want to be able to get a good idea of the gas port errosion and throat wear.

    I have a very interesting write up comparing the Scar to the AR that I will be posting in coming days. One thing I found was going from H to H2 to H3 buffer weights, on average drop the rate of fire of the 6933 about 60 rounds per weight change. I have tons of other info coming shortly.

    So that is my logic for wanting to cut the barrel.

  10. #20
    Join Date
    Sep 2007
    Location
    AZ
    Posts
    27,217
    Feedback Score
    14 (100%)
    You can measure the lead in the throat without destroying it. But get pics of everything in any case.

Page 2 of 3 FirstFirst 123 LastLast

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
  •