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Short Stroke problem

Discussion in 'GATE AR-15 Forum' started by EASY, Jan 22, 2014.

  1. EASY


    Oct 23, 2000
    Marietta, GA, USA
    Shooting buddy has a new DPMS 20 inch barrel AR in 5.56. Right out of the box it would short stroke every couple rounds. After checking the whole gas path and resetting the gas rings it improved but not completely. We tried many magazines and several types of factory and GI ammo. The dealer tried it an pronounced it good but the problem persists. Anywhere from 20 to 50 rounds it will short stroke every time and trap the next round with the front of the bolt. Short of sending it back to the factory, any suggestions?

  2. Constructor

    Constructor Moderator

    Dec 10, 2009
    Check the gas port in the barrel, it should be .093 or 3/32" or a rifle gas 20".
    Some cheap ammo is known to be weak. If Winchester White box doesn't cycle there is a problem. If you want to use weaker ammo like 223 then you may need to open the gas port to .096 or .098. Use wire sized drill bits from a machine shop supply like Travers, MCS, Grainger etc.

  3. railpig314


    Jun 25, 2015
    DPMS is the problem!