The Harris Mod

Discussion in 'Mini-14 Forum' started by steve4102, May 6, 2012.

  1. steve4102

    steve4102 New Member

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    I'm thinking about giving the "Harris" mod a try on my Mini-30.

    The Harris mod consists of removing a few thousands off the gas block end of the slide, so when the action is closed there is a .001-.003 gap between the slide and the gas block. The forward motion of the slide is stopped by the bolt lug and not the gas block.

    Seems rather simple, but on my Mini-30 I would have to remove about .250 off the end of the slide for this to work. That's to much and I think it would cause more problems.

    I bought a used slide off of GB to experiment with. For this to work I think I will have to fill in the rear most part of the slide cut out and then have it machined so the slide and the bolt lug make contact.

    What do ya think? Gunna work? Crazy? Worth a shot?
     
  2. tri70

    tri70 New Member

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    I have done this to all 3 of my minis, I believe the kinetic pressure against the gas block is bad if it is not square and even. I believe it helps increase the accuracy because the 1st mod most of us do is adjust the gas block screws for even pressure against the barrel. Same thought about the gas block, even the surface pressure. I have not ill affects, I use a vacuum cleaner belt for a buffer on both ends of the op rod.
     

  3. steve4102

    steve4102 New Member

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    How much material did you have to remove off the gas block end of the slide?
     
  4. tri70

    tri70 New Member

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    I just removed the tab and tried to keep the op rod end as square as possible. I know with the bolt resting forward it will not touch the gas block unless I use a buffer. I know the bolt is sharing part of the load now but like I said, I have not seen any damage on the bolt or any ill affects to report.
     
  5. Clem

    Clem New Member

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    While you are looking into issues associated with the op rod and gas block, you might want to consider installing a smaller gas port bushing and a stainless gas pipe if your gun is blued. The smaller gas port bushing will reduced the strain on the gun when it is fired and decrease the distance the expended case is thrown. The stainless gas pipe on a blued gun will help to prevent corrosion from locking up the gun during extended inactivity.