Bolt Disassembly / Cleaning Warning

Discussion in '223 / 5.56 MVP and Variants' started by RoyP, Aug 29, 2013.

  1. Jeb Member

    Member Since:
    Oct 26, 2013
    Message Count:
    79
    Trixter i had the same problem and pretty much did the same fix as u. I have shot about 300 rounds through it without a problem now
  2. trixter New Member

    Member Since:
    Jan 8, 2014
    Message Count:
    3
    Thanks everyone. Shaun, and MechTech for the photos. That was the key to making mine usable again. Thanks too to Jeb.

    I also watched a couple of great videos about the bolt dis-assembly and re-assembly.
  3. trixter New Member

    Member Since:
    Jan 8, 2014
    Message Count:
    3
    Over the weekend I went Squeek hunting and shot about 200 rounds not expecting trouble again, but after about 150 rounds, the firing pin problem reared it's ugly head again. I had to cock and try to dry fire about 12 times before it would start working again. I guess that was not enough 'fix' after all. I am going to disassemble and look again at the hole through the bolt head pin and see if there are any rough edges. It doesn't quite make sense that it happens.
  4. Ghost Impala New Member

    Member Since:
    May 26, 2014
    Message Count:
    6
    Good evening all, or good morning depending upon where you are. I wanted to tag onto this post because I experienced the exact issue described above after about 10 rounds. I was not happy as I thought the firing pin broke. I took the bolt apart using a post from this site - thanks fellas, and did not find a notable issue (busted pin or spring). What I did find we're 2 small pieces of brass I imagine are primer bits. Factory box ammo. Upon inspection of the shell casings I noted that the primer indents were deep and hard enough to create an edge around the dimple (like a crater). I put it back together and it's now dry firing perfectly. Wanted to say thanks for posting how to take the bolt apart and offer hope to anyone who's having the same issue. Does anyone know why the pin is striking the primer so hard and can I back it off?
  5. Frank Mc Member

    Member Since:
    Sep 4, 2012
    Message Count:
    50
  6. Frank Mc Member

    Member Since:
    Sep 4, 2012
    Message Count:
    50
    Good afternoon all,
    Just to let you know, that I have 5,776 rounds thru my MVP as of this morning. The bolt has never been apart since I purchased the rifle. Just keeps on ticking.
    It has to be to most dependable piece of equip I have ever owned.(Knock on wood)

    Frank
    Barry Hedrick likes this.
  7. George New Member

    Member Since:
    Sep 21, 2014
    Message Count:
    8
    I have had primer extrusion issues with my MVP Thunder Ranch 5.56 rifle. It seems that the primers in most brands of ammo are cratering from the firing pin hit (maybe?). When I mount a suppressor primers are being extruded into the firing pin hole and jamming up the firing pin. So far this is happening with PRVI match .223 ammo and Fiochii 69g match.
  8. Konstantin New Member

    Member Since:
    Feb 12, 2015
    Message Count:
    8
    Hi everyone! Had same problem with the pin yesterday after 70 shots. Firing pin jam. I disassembled the bolt for cleaning and firing pin check and i found small peace of brass metal inside. I think it was from my ammo capsule or something and it blocked the pin. Cleaned the bolt and the gun it self and it seems working now. I used norrinco 5.56 ammo, I think firering pin over penetrated the capsule of some rounds and that why i found some metal peace in my mossberg bolt.
  9. wood chucker Moderator

    Member Since:
    Dec 19, 2012
    Message Count:
    1,605
    Back in the real early 1990's I found Norinco yellow box 5.56 to be a little hot. IIRC the brass was pretty consistent and it was good ammo.
  10. Konstantin New Member

    Member Since:
    Feb 12, 2015
    Message Count:
    8
    Date is 1995 for mine, yellow box. i think it still not bad ammo for the price. Going to the range next week to test them again.
  11. Dwade New Member

    Member Since:
    Dec 9, 2014
    Message Count:
    11
    Took mine prairie dog hunting yesterday, after 3 failures to feed, I yanked the bolt out and took it apart. Sure enough the spring and retaining ring are both gone. Anyone know if Mossberg will ship these? I cut a few coil off of a small spring and made a makeshift replacement. Would like to get a new one on the way though.
  12. Msmith New Member

    Member Since:
    Feb 24, 2015
    Message Count:
    1
    New guy here. Just wanted to say thanks guys. I just picked up an MVP Patrol for a really good price. Then I figured out why. 50% of the time it wouldn't strip a round from the mag. I tried several brands of mags with the same results. Then I saw a post where a guy put Velcro in the grove at the back of the magwell. This helped a lot but still had a 25% failure rate. Then I saw this thread. Turns out my "drop arm" was not spring loaded at all. It was just flopping around. Took the bolt apart and the spring was there but it was crunched pretty bad. The gap in the retaining ring was lined up with the spring somehow allowing this to happen I guess. I was able to bend it back in shape and she's now stripping rounds out of the mag perfectly. Every mag type I've tried has worked great so far. I don't have a lot of hopes of getting a replacement spring, but I'm going to try.

    Thanks again,
    Matt Smith
  13. Pastryslayer Member

    Member Since:
    Jun 25, 2014
    Message Count:
    80
    &$&!. While replacing my extractor and taking care to retail the ball and spring, I managed to lose this spring. Even after reading this thread and reminding myself to watch out for it. Anybody have luck getting a replacement from Mossberg? Failing that, a readily adaptable hardware store alternative? So annoyed with myself. Thanks.


    Sent from my iPhone using Tapatalk
  14. wood chucker Moderator

    Member Since:
    Dec 19, 2012
    Message Count:
    1,605
    Brownells or Wolff gun spring would be faster.
    My advice is ask the fellas here to measure the springs length, diameter, wire thickness and number of coils so you can get the right one.
    Robert and Mike might already have the data handy.
  15. Pastryslayer Member

    Member Since:
    Jun 25, 2014
    Message Count:
    80
    Robert was going to look at it tonight and see about a fix. It's a weird spring. I doubt anybody has anything on hand. Wondering what uses those springs commonly. Watches? Cameras? Who knows.


    Sent from my iPhone using Tapatalk
  16. Pastryslayer Member

    Member Since:
    Jun 25, 2014
    Message Count:
    80
    Ha! Crisis averted. While trying to make a new spring, I fumbled my donor spring to the floor. While looking for it, I found my original factory spring in the carpet. Crazy, but I'm back in business.


    Sent from my iPhone using Tapatalk
    Keith likes this.
  17. Ulfberht Training and mentoring the next generation.

    Member Since:
    Dec 23, 2015
    Message Count:
    111
    Is there supposed to be a steel ball that sits on top of the spring under the extractor?

    I just received and installed a new extractor, but it wabbles...

    Gonna go fetch the operator's manual.

    The bottom side of the extractor is concave; seems like a fit designed for a ball.

    Odd because there was no steel ball when the first extractor broke (after less than expected rounds fired).

    Addendum: Page 16, number 17; Detent Ball
  18. Keith Moderator

    Member Since:
    Dec 7, 2014
    Message Count:
    1,192
    Yes, there should be a ball under the extractor. In fact, when I ordered an extractor from CHP, I got a spring and ball just in case my removal and installation method was poor and one or both went flying across the room. Thankfully, it did not, so I have a spare of all three parts now.

    Anyway, yes. The ball sits on top of the spring and is held down with a thin, flat tipped screwdriver while sliding the extractor into place. The ball will lock the extractor in place once it sets into the detent in extractor.
    Ulfberht likes this.
  19. Ulfberht Training and mentoring the next generation.

    Member Since:
    Dec 23, 2015
    Message Count:
    111
    The dentent & other parts Rob sent work perfectly!

    Now that I have the "bugs" worked-out and the missing parts installed, I can see how the rifle is supposed to function.....and it functions way beyond my expectations and my (age 55+) abilities.....and a fun shooting rifle it is!

    As it appears now, the original extractor was already broke and the original detent was missting when the rifle arrived "N.I.B.".

    No plans to buy another Mossberg until their QA improves, but I will definitely keep this rifle.

    Grandkids are going to enjoy it....;)
  20. GrocMax Active Member

    Member Since:
    Jun 12, 2014
    Message Count:
    166
    Those of you who are heavily cratering primers might want to check for excessive headspace via a no-go gauge.
    Ulfberht likes this.

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