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  1. #1
    Join Date
    Jan 2006
    Posts
    143

    Default AK gas block 90 degree vs 45 degree

    With all this talk about AKs and the distinct possibility of a imminent political shift in the good ole U.S., I have been giving serious thought to building a couple of rifles.

    My neighbor has a couple and we have discussed the particulars of building vs just buying one. One of the things he said was that the standard gas block on an AK -47 is of the 45 degree variety and that the gas flow provides for "shear force" on the bullet and that this "shear force" can shave the bullet to a degree which can effect accuracy.

    I have found a 7.62 x 39 barrel that has the 90 degree gas block but I don't really know the validity of the above noted accuracy issue. K-Var sells 'em but they are pricey.

    Anyone know about this?

  2. #2
    Join Date
    Jun 2006
    Posts
    430
    I've never seen evidence of it myself, but allegedly bullet shear became an issue with high velocity ammo like 5.45x39mm, that's why AK-74 production line switched from 45 to 90 degree gas block in 1975-76. If you are planning on a 7.62x39mm AK, a 45 degree gas block is fine unless you are really trying to build a tack driver (good luck). Bullet shear must not be a serious problem because Romania still uses 45 degree gas blocks on their 5.45mm AK-74 (AIM-74) variant. I have also heard that at some point drilling was refined so that the gas port always went into a barrel groove instead of random placement among the lands and grooves. I wouldn't worry about it in 7.62x39mm in any case, it's an AK!

  3. #3
    Join Date
    Sep 2003
    Location
    Brazil.
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    17,203
    Doesn't the sniper version ( Draganov ?) also have a 45 degree gas block ?
    Regards,
    Anthony.
    If you have to fight, do not fear death.
    We will all die one day, so fight skillfully and bravely!
    And if it is to be that you die, then at least go to God proudly.
    Meet him as the proud warrior that you once were, and not as a sniveling coward.
    Nobody lives forever.

  4. #4
    Join Date
    May 2006
    Posts
    367
    I always thought they converted to 90 degrees to lower production costs. Much cheaper and easier to drill straight down into the barrel than at a 45-degree angle.

  5. #5
    Join Date
    Jun 2006
    Posts
    430
    The downside to 90 degree blocks is that it's much harder for your peasant army to effectively clean their gas ports, a big downside when you use corrosive ammo.

  6. #6
    Join Date
    Jan 2005
    Location
    Tucson, AZ
    Posts
    27
    "Doesn't the sniper version ( Draganov ?) also have a 45 degree gas block ?"

    Therefore, the Dragunov (the real Dragunov as in SVD and not the Romanian PSL/FPK) is different from that of the kalashnikov gas system...

    Far as I know... and have been told... by the weapon plants in Russia and in Bulgaria... the 45 vs 90 degree gas block is purely a cosmetic one...

    Take it for whats its worth... but... my 47's and 74's just shoot fine with no appreciable difference between the two...

    Dunno what else to add...

    Y-
    Yancey Harrington

  7. #7
    Join Date
    Oct 2003
    Location
    In the world but not of it
    Posts
    3,720
    Dunno nuthin 'bout no Commie engineering. Got any drawings of this part?

  8. #8
    Join Date
    Jan 2006
    Posts
    143
    Thanks to all who replied. Seems to be a non issue but I figured I'd inquire since the 7.62 x 39 barrel is available with a 90 degree gas block.

    I can see however, how drilling the gas hole in the barrel might be a little trickier at a 45 degree angle and if done wrong might screw up the lands and thus accuracy.

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