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Thread: AR15 Performance Super Bolt

  1. #61
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    Quote Originally Posted by constructor View Post
    The only bolts in over 20 years I have had fail were Y/M, they broke at the cam pin hole. I've seen a few bolts from the largest producer of civilian ARs in this country that looked like the lugs were compressing, further inspection showed they were very soft. I know someone who built a grendel using a 7.62x39 bolt from the same company, after several stiff rounds the cases started taking the shape of a belted magnum, he checked and found the lugs were .008 shorter. I believe those bolts to be 8620 and not heat treated properly.
    I checked into Carp 158 4 years ago, found out that all of the material was allocated to 2 companies that had DOD contracts to supply Colt and FN.
    I ran shear tests on the carp bolts and ours, for all out strength our lugs are stronger. Fatigue test depending on the heat treat process also showed an improvement over the 158 bolts. I designed the bolts with a large radius on 3 sides of the lugs for a reason. There are other factors that are important other than just looking at the specs of the material. Some 9310 bolts on the market are or were too hard and brittle, the surface will develop cracks.
    I've only made about 15000 bolts in the last 3 years, don't really need to push the sales, it's more to supply the rifles we build. There has not been 1 single bolt broken in 556,6.8 or 7.62x39.
    There are some Fed teams using our 6.8s I have no doubt our bolts will last longer than any other 6.8 bolt on the market.
    Something is going on with the 7.62x39, a couple of companies are testing heavily and asking for quotes on tens of thousands of bolts. It seems ours held up under full auto fire better than the rest.

    As for the 556s it's too easy for us to buy Carp 158 bolts complete from a DOD contractor for less than it cost us to machine our bolts. I need our machine time for other projects, and I am dialing in our machining process on a new alloy that is apx 40% stronger than Carp 158 and 9310. It takes time to figure out the correct carbide grade, coating and chip breaker to turn out parts quickly.
    I don't plan on making 556 bolts again unless we can't buy enough to supply our own builds just like what happened with the 6.8s, time will tell.
    If your bolts are so superior why settle?

    You menion stopping production on 5.56 bolts because you can get "inferior" bolts cheaper.

    Doesn't make much sense to me.

  2. #62
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    Quote Originally Posted by E-man930 View Post
    Just FYI - 9310 seems to get bashed a bit for not being tried and true like C158, yet KAC makes their E3 bolts out of it.
    Do you have a link to the source of this info?

  3. #63
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    Quote Originally Posted by constructor View Post
    The only bolts in over 20 years I have had fail were Y/M, they broke at the cam pin hole. I've seen a few bolts from the largest producer of civilian ARs in this country that looked like the lugs were compressing, further inspection showed they were very soft. I know someone who built a grendel using a 7.62x39 bolt from the same company, after several stiff rounds the cases started taking the shape of a belted magnum, he checked and found the lugs were .008 shorter. I believe those bolts to be 8620 and not heat treated properly.
    I checked into Carp 158 4 years ago, found out that all of the material was allocated to 2 companies that had DOD contracts to supply Colt and FN.
    I ran shear tests on the carp bolts and ours, for all out strength our lugs are stronger. Fatigue test depending on the heat treat process also showed an improvement over the 158 bolts. I designed the bolts with a large radius on 3 sides of the lugs for a reason. There are other factors that are important other than just looking at the specs of the material. Some 9310 bolts on the market are or were too hard and brittle, the surface will develop cracks.
    I've only made about 15000 bolts in the last 3 years, don't really need to push the sales, it's more to supply the rifles we build. There has not been 1 single bolt broken in 556,6.8 or 7.62x39.
    There are some Fed teams using our 6.8s I have no doubt our bolts will last longer than any other 6.8 bolt on the market.
    Something is going on with the 7.62x39, a couple of companies are testing heavily and asking for quotes on tens of thousands of bolts. It seems ours held up under full auto fire better than the rest.

    As for the 556s it's too easy for us to buy Carp 158 bolts complete from a DOD contractor for less than it cost us to machine our bolts. I need our machine time for other projects, and I am dialing in our machining process on a new alloy that is apx 40% stronger than Carp 158 and 9310. It takes time to figure out the correct carbide grade, coating and chip breaker to turn out parts quickly.
    I don't plan on making 556 bolts again unless we can't buy enough to supply our own builds just like what happened with the 6.8s, time will tell.
    This made sense to me.

    I see no need to deviate from the standard 5.56 bolt given its decent reliability and ease of procurement. As long as you stick to known good manufacturers you should be fine.

    Seems like the original idea came for his bolt because he couldn't find a dependable source for 6.8 bolts. I've been researching 6.8 lately and it seems to be a pain to find C158 bolts. Most tend to be 9310 so I've been looking at these for the slightly improved geometry.

  4. #64
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    Quote Originally Posted by sinlessorrow View Post
    If your bolts are so superior why settle?

    You menion stopping production on 5.56 bolts because you can get "inferior" bolts cheaper.

    Doesn't make much sense to me.
    The guy below you figured it out for you.
    We can't keep up with the amount of machines we have.
    556 bolts don't break that often.
    We can buy C158 556 bolts cheaper than we can machine them.
    I don't like running CNCs 12 hrs a day 7 days a week.
    I don't need the money, rather spend time on the lake.
    AR15performance
    TRUMP 2020
    The 6.8 is the best choice for hunting deer and hogs with an AR15.

  5. #65
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    constructor,

    Are you playing around with Aermet 100?
    Last edited by E-man930; 03-13-12 at 19:39.

  6. #66
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    Quote Originally Posted by E-man930 View Post
    constructor,

    Are you plating around with Aermet 100?
    No not Aermet, there are several metals that are similar in strength 290/250 range. When considering strength those numbers mean a lot but impact resistance and then heat treating them to the proper hardness to obtain overall toughness may be more important. Too soft, they compress. Too hard, they crack. In order to get to a 290 tensile/250 yeild the material must reach maximium hardness which isn't always the best for long term fracture toughness.
    Typical bolt material is in the 180/160 range and hardly ever break due to lack of strength, it is the long term fatigue that kills a bolt.
    AR15performance
    TRUMP 2020
    The 6.8 is the best choice for hunting deer and hogs with an AR15.

  7. #67
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    Bringing this back to life with a question for Constructor -

    The cam pin hole is a known weak link on the AR bolt. You increase the diameter on your superbolts to make them stronger. You do not radius the edges of the cam pin holes in the bolt. Why leave them sharp as this makes them more like to start cracking there?

  8. #68
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    Haven't ever purchased any ARP products but when I built my first 7.62x39 AR the two most popular choices for an 'enhanced' bolt was ARP & LMT. ARP stopped making them when I finally got around to upgrading so I went LMT instead.

    7.62x39 ARs are typically harder on their bolts which have thinner walls, so anyone who makes a good 7.62x39 bolt will make a top notch 5.56 bolt.

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