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Thread: durability of 308/8mm ak conversions

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    tired of idiots vz58's Avatar
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    Default durability of 308/8mm ak conversions

    Those of you who have converted, how many full power rounds do you have through the build?

    I am seriously considering using a spare L1A1 barrel, a yugo trunnion and bolt for a 308 build. I just worry about safety and durability.

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    Happy Camper hcpookie's Avatar
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    I'll be honest. I built mine on the premise that some of the factory 308 guns were basically a converted 7.62x39 build, after all those comparison photos that were shared of the Saiga .308, the Yugo, and I think a Galil? bolt. The locking lugs are the same on some of them, and so was the size of the lugs on the trunion.


    My SVU clone is a rough ride with surplus military ammo (which we all know is really hot) for one simple reason - the gas port is too large. I cut it to the standard AK-47 size of gas port. .177" I believe. Venting the gas tube was an IMMENSE help!

    The load I use in it now is one of the recommended accuracy loads on the Nosler website. You can shoot it all day long and it feels like a normal AK-47.

    I inspect it regularly since it is a bullpup and I don't want it blowing apart and into my face. It is built on one of those DPH bent flats (remember those?) and is mostly a Romy G kit. I've had about 150 rounds through it, both hot and mild, and no signs of excessive wear or peening. Headspace has not budged at all. And I check it after almost every range trip.

    The problem I had with the gas block was due to it being bored out too much, making the base too thin, and the replacement block I installed is A-OK.



    I would have no problems using this as a "go-to" gun.



    If I were to do it again, I would:

    1. Use some 4130 tube steel as the base, with a factory gas block welded to the tubing.

    2. Drill a smaller gas port.
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    Gunco Rookie Oswald2001's Avatar
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    My IMI .308 Galil has shown no signs of excessive wear.

    It just keeps chuggin' along.


    I haven't heard of an problems with either IMI .308's or .308 clones that were well built.

    Also, the Yugo's used 8mm in their sniper rigs 'forever' and I have never heard of any problems there either.


    YMMV

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    tired of idiots vz58's Avatar
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    yes but they were designed from a factory, I am thinking of yugo 762x39 bolts and trunnions.. the yugo 8mm have longer lugs

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    Gunco Regular Shadow Walker's Avatar
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    I am in the middle of converting a Yugo front trunnion to accept M-14 magazines. When this is completed, I will then re-chamber the barrel to .308.

    Right now it is all just a RPK parts kit, but time will tell.

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    tired of idiots vz58's Avatar
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    Well broke down and ordered the yugo BC, bolt and bulged trunnion for a 308 on an extra L1A1 bbl I have here.
    I saw cold steel has 2 blanks, one rpk bulged and one yugo bulged. Anyone know the difference?

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    Gunco Regular allesennogwat's Avatar
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    I'm not sure the Yugo 8mm bolt lugs are longer. They might be though. The other half is the receiver or trunnion. Originally the Yugo 308, Galil 308 and Valmet 308 had standard size two lug bolts. Both Saiga and Vepr tried to make 308's with two lug bolts. These failed the newer CIP 125% overpressure test. So the Russian 308 AK's use three lug bolts. The Yugo 308 bolt has an extended bolt face and the barrel is not as far in the trunnion. This is for easier feeding. As long as the ammo ism't overpressure the standard two bolt lugs seem to be enough but the CIP tests do show this is borderline. Bolt thrust should a factor of area and pressure. The area being the cartridge head and the pressure being chamber pressure. I'm not sure how this translates to rimmed catridges like 7.62x54R. I'm not even sure if these are the only factors. I haven't researched it that much.

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    tired of idiots vz58's Avatar
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    The bolt thrust should actually be the outer diameter of the case at the breech face times the pressure, rimmed or rebated rims do not alter it.

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    No Hope For Me 1biggun's Avatar
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    I'm not sure how this translates to rimmed catridges like 7.62x54R.
    The bolt thrust should actually be the outer diameter of the case at the breech face times the pressure, rimmed or rebated rims do not alter it.
    Im pretty sure you use the INSIDE DIAMITER of the case head to factor the bolt thrust. If a case was say very very thick for example the thrust would be the same as a very very thin case as long as the ID was the same.

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    No Hope For Me 1biggun's Avatar
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    I saw cold steel has 2 blanks, one rpk bulged and one yugo bulged. Anyone know the difference
    bump for a answer to this as well I am going to likely go this route on my Yugo buillds.

    Also I am going to get some material to make LH ejecter rail blanks. I plan on bending them in a break and leaving enough material to make the ejecter tip further back as this will be nessacry to eject loaded 308 length rounds. If any one is interested I may be willing to make a few extra. the will likely be just a 90 degree bent blank that will have to be completly cut and fitted but it will be the correct metal so it can be hardend . I dont know of another source of rails for this. If you guys do, Im all ears. on my initial 308 build I just welded two rails together but it was pretty cobbled.

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