cut my barrel down?

Discussion in 'AR15/10 Rifles' started by bigry26, Feb 1, 2012.

  1. bigry26

    bigry26 Well-Known Member

    Dec 11, 2011
    I have a 24" heavy barrel on my 223 AR and am thinking about cutting it down. If I do I will have it cut to 20". It is real heavy in the front. What are your thoughts on this. Thanks Ryan

  2. Kevin Thomas

    Kevin Thomas Well-Known Member

    Feb 16, 2009
    Your rifle, your choice! You'll lose a little velocity out of this, but probably not enough to make a huge difference in the field. It may well balance better for you, but there's also other ways to change that (stock weights, etc.) if you need to. Depending on the use here, I'd probably try to redistribute the weight in the butt first, and go to cutting the barrel as a last resort.

    Again, no matter what anyone suggests, it's ultimately your choice.

  3. LouBoyd

    LouBoyd Well-Known Member

    Oct 15, 2007
    An additional consideration on shorting AR-15's is the length of the barrel past the gas port.
    There are four common gas port loactions for AR-15. Those are rifle, mid, carbine, and pistol.
    The pressure and the duration of the pressure after the bullet passes the gas port to the time the bullet exits the muzzle determines, along with the diameter of the gas port, the energy available to drive the bolt carrier. It you cut off the barrel you may need to enlarge the gas port a bit to make up for the reduced gas impulse. If you cut off the barrel within a couple of inches of the gas port the rifle may not function at all. it is possible to move the gas port to a different location.

    Tuning AR-15 can be difficult. They're designed to be fairly forgiving, but there are a lot of adjustable variables:
    Barrel length
    Gas port location
    Gas port diameter
    bolt carrier mass
    buffer mass and structure
    buffer spring rate
    buffer spring length
    Stock length( spring chamber)
    Bullet weight
    powder weight and burn rate (several interrelated parameters)
    Muzzle device (particularly a suppressor)

    It's a lot easier just to purchase a new upper and keep the longer barreled upper for when you want higher velocity. 24 and 26" AR-15s generaly work well on bipods or bags.
  4. msalm

    msalm Well-Known Member

    Jul 18, 2007
    Worse case is after cutting to 20" you have to open up the gas port, which is easily done. .093" is the standard diameter for the 20" barrels, but usually you can get by with .088-.090".