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Thread: 243,260 or grendel for ak

  1. #31
    tired of idiots vz58's Avatar
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    Will post the $20 bbls when they get some 223 in stock for me..... someone beat me to them, was it someone here???

  2. #32
    blu
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    wasn't me :-)

    i just want affordable .243's.

    good luck on the .223.

  3. #33
    Gunco Regular Gunter's Avatar
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    Not me either.

  4. #34
    Gunco Member santanatwo's Avatar
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    Unhappy

    Quote Originally Posted by vz58 View Post
    possibly, the question is whether or not the 762 bolt can handle the higher pressures. The trunnion is the same (in the critical areas) as the 308 trunnion. The difference is the lugs on the bolt. The 308 bolt has the extractor area moved forward away from weakening the lugs.
    pressure on the 308 and 243 is significantly higher than 762 plus the diameter of the base is larger (more area pushing against bolt)
    we had a very similar debate on saiga-12.com, when some newb decided it was a good idea to grind off the "extra" 3rd lug on his saiga 308.

    there is a very good reason whyt he ruskies decided it NEEDS a third lug and other design modifications.

    If it was safe, don't you think they would have just left good enough alone, rather than spending all the time and money to redesign/retool?

    I STRONGLY feel these mods are extreamly unsafe.

    Remember that a lot of old british 303 rifles were changed to 308. and while the vast majority of them have not blown up YET (there have been some failures IIRC), it is an unsafe practice. Especialy since 308 ammo is loaded to higher presures than the military equivalant 7.62 x 51 NATO. The indian 308 rifles were built using stronger steel.

    And 243 is just as high PSI as the 308. The PSI is higher than the 7.62x39, and the area (square inches) is also higher. thus producing much more stress on the lugs. You can do the math yourself, take the area (in square inches) (that's pie R squared) of the case head, and multiply it by the chamber pressure, you will get a MUCH HIGHER value for the 308 (and equivilants) vs the 7.62 x 39.

    A bulged yugo trunion MAY be safe enough (I still wouldn't want to take that risk), but a normal romy g trunion is deffinitely not. I would be concerned with any 7.62 x 39 mods.


    PLEASE BE SAFE, PEOPLE






    I strongly believe the only safe conversion is the 308 saiga ---> 243 (etc)


    which I am currently working on.

  5. #35
    Happy Camper hcpookie's Avatar
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    santanatwo, welcome to Gunco.

    You really should read through the volumes of data we have collected on this particular sub-forum about chamber pressures, bolt thrust, etc. etc. before making blanket statements.

    We're not your normal group of idiots - NO ONE HERE wants to go to the hospital with a bolt stuck in their eye. I'm glad you are concerned about safety. I really am! However I'm not going to restate what has been said here so many times. Just read the info, and understand we are planning these very carefully. 'nuff said!


    Quote Originally Posted by santanatwo View Post
    we had a very similar debate on saiga-12.com, when some newb decided it was a good idea to grind off the "extra" 3rd lug on his saiga 308.
    Please don't lump us into the same category as some dumbass who would do something so reckless.
    Gunco Member #10

    http://pookieweb.net


    The "original" Boltcutter Rivet Squeezers:
    http://pookieweb.net/AK/rivet/boltcutters/boltcutter.htm


    Project Pink - the Pink and Blue AK-74:
    http://pookieweb.net/pink/pink.htm

  6. #36
    Gunco Member g2busmc's Avatar
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    well said HC

  7. #37
    tired of idiots vz58's Avatar
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    Welcome santanatwo, there have been 308 conversions, and like several others we are waiting to see how they hold up. Thanks for the concern, I think te points you have brought up are valid and, infact, have been brought up several times by many of us. Additionally, some of us reload and will be using reduced charges in these guns.

  8. #38
    No Hope For Me 1biggun's Avatar
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    http://www.gunco.net/forums/f244/308-ak-18443/

    Go back several years read all the posts from this area. I understand your concern however there is a lot of thought put into these as stated above. the CIP pressure test are at a higher pressure than the the SAMMI. a two lug 308 ak would LIKELY pass a SAMMI proof test.

    I have yet to see any proven account of a ak bolt failing ever (excluding sabotged explosive loads) except due to obstructed barrel this included calibur conversions. while this proves nothing it does give credit to the strength of these parts.
    I have loaded standard 7.62x39 up to the point of blowing primers (do not attempt this ) and likely well over 60,000 PSI. again I am not recominding this practice but just pointing out that even an abused action holds up.

    the formulas you are quotin are valid regarding the increase in case head differance and the differance in pressures. in fact this site is the first that posted the formulas and numbers regarding AK,s AND CONVERSIONS TO 308 on the net to my knowladge. the only area that these facts dont prove is what will the AK action hold up to. these facts and figures only prove that the action is being subjected to a higher pressure. they do not prove that the action is not capiable of handeling it safely! again read everything in the calibur conversion area. my original thread on a 308 AK conversion is like 4 years old.

    THE $64,000.00 QUESTION IS AND REMAINS, WHAT IS THE SAFE WORKING PRESSURE THAT THESE ACTIONS CAN HANDEL!
    IT HAS BEEN SAID THAT THE RUSSIANS WENT TO A 3 LUG DESIGN DUE TO THE 2 LUG FAILING THE EUROPIAN PROOF TESTS. ( SOME WERE THOSE PRSSURES ARE STATED) THOSE NUMBERS ARE WAY HIGHER THAN ANYTHING THAT A NORMAL LOAD WILL EVER PRODUCE SHORT OF AN OBSTUCTED BARREL.

    the guys who have built these have yet to report even a increase in head space on a build.
    I personaly was very sceptical as well when I propsed a conversion years ago.

    I hand load and I have posted near maximum loads for the 308/ 7.62x51 that are actually at or below the pressures of a 7.62x39. the winchester powders come to mind.

    it is obvious that you are not a fool and every fact you stated is likely correct. just keep an open mind untill you review all that has been said here. welcome to gunco. I hope you post some pics of your stuff.

  9. #39
    Gunco Regular Gunter's Avatar
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    I'll throw something else out here. Anyone ever see a Remmy 788? One of the guys at work brought one in for me to take a look at because it was very hard to push the bolt down to lock. Three rows of three SMALL lugs in a 7mm-08 at the REAR of the bolt. From the wear the middle lugs were not even touching, just the front and back set. To me the receiver would be the first to let go because of the cutouts for ejection and for the magazine. (The problem was from the trigger pack being loose and letting the front of the sear hit the rear edge of the bolt, not from the lugs).

    Here is a good thread to read. Very interesting.

    Ikonboard Message

    Don't know whats up with the link. Look in the Your Projects section for the thread " Home built bolt action" by Heathydee
    Last edited by Gunter; 09-22-2008 at 04:06 PM.

  10. #40
    No Hope For Me 1biggun's Avatar
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    that a interesting site. now my brain hurts with all the new stuff I want to build. after the AK kits dry up I want to try a 50 BMG upper and a 300 WIN mag or simular for a ar reciver.

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