Welcome guest, is this your first visit? Create Account now to join.
  • Login:

Welcome to the NZ Hunting and Shooting Forums.

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed.

Alpine Black Watch


User Tag List

+ Reply to Thread
Results 1 to 14 of 14
Like Tree11Likes
  • 10 Post By Kiwi Greg
  • 1 Post By MassiveAttack

Thread: AR15 Issue?

  1. #1
    If it goes Boom; I'm there faregame's Avatar
    Join Date
    Mar 2012
    Location
    Whangarei
    Posts
    1,031

    AR15 Issue?

    Hi

    Mate has just got a AR15, and had suppressor put on it

    It seems to be inconstant with grouping even at 50m - good ammo too

    Not tried without the suppressor though

    This is what the cases look like - very dirty - had maybe 30-35 rounds fired

    Overgassing??
    Whats the signs of that

    Name:  IMG_2123.JPG
Views: 427
Size:  132.6 KB

  2. #2
    Terminator Products Kiwi Greg's Avatar
    Join Date
    Dec 2011
    Location
    Nelson
    Posts
    5,805
    As soon as you put a suppressor on an AR you need to either increase the BCG weight or put an adjustable block on it, they will over gas straight away, the amount depends on the suppressor & its design.

  3. #3
    Member dogmatix's Avatar
    Join Date
    Dec 2011
    Location
    Northern Gaul (Pukekohe)
    Posts
    4,218
    That's normal, even without a suppressor after 30 rounds or.
    Suppressor certainly increases back pressure, so best to have an adjustable gas block to bleed some gas off.
    Good suppressors like ODL have a design which reduces back gas.
    Welcome to Sako club.

  4. #4
    Banned
    Join Date
    Apr 2015
    Location
    Land of the Long White Cloud
    Posts
    1,001
    The dirty cases are typical of suppressed AR15s. It comes from back pressure from the suppressor. Not a lot you can do really.

    Try it without the suppressor and you'll see the difference.

    As to "It seems to be inconsistent", without giving specifics of the group size, type of rest and scope and how good the shooter is, there's not much to go on.

    Inconsistent as in 1 inch to 10 inch groups? 6 inches to 9 inches? 2 inches to 4 inches?

  5. #5
    If it goes Boom; I'm there faregame's Avatar
    Join Date
    Mar 2012
    Location
    Whangarei
    Posts
    1,031
    Thanks

    I'll ask what they actually did to the rifle

    Groups - 4 inch plus at 50m - some really close then opens up

  6. #6
    Member 300_BLK's Avatar
    Join Date
    Aug 2014
    Location
    Central North Island
    Posts
    2,465
    Dirty Brass is normal with a can.

    Check:

    Groups without suppressor
    Barrel nut is tight (can you move the barrel back and forth with your hand whilst holding the handguard)
    Scope tracks correctly (when you adjust 1" does it move 1")
    Scope mounts are tight
    Barrel twist is fast enough for projectile weight (1:12 up to 60 grains, 1:9 up to 69 grains, 1:8 up to 75 grains, 1:7 up to 90 grains)
    Gas Key (the thing on top of the bolt) is staked and not moving
    Gas tube / Gas block is all tight

    Let us know after that...

  7. #7
    Terminator Products Kiwi Greg's Avatar
    Join Date
    Dec 2011
    Location
    Nelson
    Posts
    5,805
    Quote Originally Posted by faregame View Post
    Thanks

    I'll ask what they actually did to the rifle

    Groups - 4 inch plus at 50m - some really close then opens up
    4" at 50 metres...

    Please give the shooter a rifle that groups well & get him to fire it.

    If no improvement throw him in the nearest creek, if there is an improvement throw the offending AR in the nearest creek...

    If inconclusive play it safe & throw both of them in the creek....

    Disclaimer these are figurative terms only

  8. #8
    Member
    Join Date
    Dec 2012
    Location
    Dunedin
    Posts
    544
    adjustable gasblock ,make sure can is on tight if no change throw in creek far cheaper than playing around with these things as the are a fast track to financial ruin.

  9. #9
    Member Beavis's Avatar
    Join Date
    Dec 2011
    Location
    The Cape
    Posts
    4,090
    Even with an adjustable block your brass will get filthy it's just the way it is

  10. #10
    Ejected
    Join Date
    Dec 2011
    Location
    Shaky City
    Posts
    1,446
    Like all the good things in life brass from a suppressed AR is dirty filthy stuff. It's the next round in the mag that gets it the worse and if you don't fire that round it will be corroded by the next time you pull it out of the ammo safe.

    So it's best to fire a mag until empty rather than topping it back up. I also brought a stainless steel pin tumbler to get those dirty dirty cases bling bling shiny again.
    tetawa likes this.

  11. #11
    Member
    Join Date
    Mar 2016
    Location
    Christchurch
    Posts
    303
    Quote Originally Posted by faregame View Post
    Thanks

    I'll ask what they actually did to the rifle

    Groups - 4 inch plus at 50m - some really close then opens up

    is that with no sights and off free hand ?

  12. #12
    If it goes Boom; I'm there faregame's Avatar
    Join Date
    Mar 2012
    Location
    Whangarei
    Posts
    1,031
    Sadly - nope - with scope (which is not in doubt)

    Will see once tried without suppressor

  13. #13
    res
    res is offline
    Member res's Avatar
    Join Date
    Apr 2014
    Location
    Quebec
    Posts
    3,312
    If the scope is trusted, what about the mount?


    Sent from my iPhone using Tapatalk
    Using Tapatalk

  14. #14
    Member Daggers_187's Avatar
    Join Date
    Jun 2014
    Location
    Sa'dah, Yemen
    Posts
    571
    If you run out of ideas you're welcome to send it down to me and I'll take a look at it for you?

    Dunno if you'll trust some random dude on the internet though....send me a PM?

 

 

Similar Threads

  1. Brass issue?
    By mawzer308 in forum Reloading and Ballistics
    Replies: 14
    Last Post: 15-03-2016, 10:36 AM
  2. AR15 30 round magazines USGI issue
    By robs in forum Buy, Sell or Swap
    Replies: 16
    Last Post: 04-11-2015, 11:08 AM
  3. Sako a7's possible issue
    By Grunta in forum Firearms, Optics and Accessories
    Replies: 11
    Last Post: 05-04-2014, 05:02 PM
  4. Issue with my gsp
    By Tristan in forum Hunting Dogs
    Replies: 6
    Last Post: 05-12-2013, 10:37 AM

Tags for this Thread

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
Welcome to NZ Hunting and Shooting Forums! We see you're new here, or arn't logged in. Create an account, and Login for full access including our FREE BUY and SELL section Register NOW!!