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Thread: Had a kaboom with my reloads.

  1. #51
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    Quote Originally Posted by scottcc View Post
    Could it be from AR Comp temp sensitive? As I stated it was in June and on a hot day at that. The ammo was in the trunk of the car. I was using metal 20 round mags, they were warm, then setting in the sun made them heat up more, while I was setting things up.

    For what it's worth I do trim cases, check OAL and also shake to hear powder.

    Sent from my cp3705AS using Tapatalk
    Depends on just how hot your ammo actually got. There is a thread on another forum where a guy did some pretty elaborate temp sensitivity testing and found AR Comp pretty good, actually half the variation of Varget. But he only tested up to 165F degrees. Summer...Trunk of car...Metal mags sitting in sun while setting up. That metal mag could've acted like a miniature oven. Elevated ammo temp will increase pressure, maybe not to a degree that hurts anything in a "normal" range of temps but there's a point which it will change and it can change in a rapid and extraordinary fashion. Hard to know if you went past the line.

    I suspect you had several things happen. 5.56 case, hot ammo, and a bit of bullet setback...OR...you just simply had a case head failure.

  2. #52
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    Here is what we are talking about with a web failure.




    The case on the left is a LC case, the case on the right is a commercial case. Note how much thicker the web area at the bottom of the LC case is. The case on the right will tend to let go first if pressures are right or there is too much exposed case head.

    Couple this with the back of the barrel being a tad forward and you have a failure waiting to happen. Similar can happen with soft case head if it got annealed upside down or case has been in a fire.
    Last edited by Humpy70; 12-20-19 at 10:02.

  3. #53
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    You provided good information in this thread Humpy70. Do you have a recommendation for how many times a .223 case should be reloaded before being scrapped?
    Train 2 Win

  4. #54
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    Quote Originally Posted by T2C View Post
    You provided good information in this thread Humpy70. Do you have a recommendation for how many times a .223 case should be reloaded before being scrapped?
    Case life depends on multiple things such as:

    1. How much bigger is the chamber than the unfired round. Most factory chambers are way too big. The more case swell you see .200 up from the rim the shorter the life is going to be.

    2. How much your dies size the cases back down. FL dies are not all the same size thus if you have a min size die and a max chamber your brass gets overworked THAG. The small base dies you read about are just dies chambered with a tired reamer and that allows them to make more dies before they chuck the reamer. I don't own a small base set at all and have never had any feed/extraction problems.

    3. Commercial 223 cases as a rule are softer and military cases thus when fired they will expand and this opens the primer pockets up.

    4. As indicated above you can tell the left case (LC) is heavier than the commercial case on the right.

    5. If you anneal your cases correctly you should never have a split case neck. You should only lose a case because the primer pocket gets worn out and won't grip the primer enough to give a good seal thus gas leakage around the primer will pit bolt face in a circle around the striker opening.

    6. There was a shop in the Atlanta area that made a special die that allowed one to size cases all the way down to the rim thus adding to case life. I never got one and wish I had.

    As an example of the above lets take my 30.06 chambers for a study. My chambers are cut on the 222 principle which means when the round fires the fired case neck does not expand over .002", the shoulder does not move forward more than .002" and the area above the web does not expand over .002". Thus when a fired case is removed it is very hard to tell it has ever been fired. I sometimes call it the anvil principle which begs the question you likely never saw a worn out anvil which is because it doesn't move.

    All the 30.06 ammo I have ever measured shows a head diameter on a new unfired case of .4645-4655. I have four sets of 30.06 dies, one resizes cases to .466, the next .469, the next to .471. I have measured fired cases that show .473 to .475 thus on them I use the .471 die. On my tighter chambers fired cases are sized to .469 or .466. You will find 06 dies size .466 to .469. So basically I know and log on my log book for each rifle what size FL die I use to resize cases.

    As a rule military brass from LC is much harder than commercial so should hold up longer. Also you might get Wolfe primers as they are a tad bigger that most milspec small rifle primers.

    How long will they last? Don't know. I have one 30.06 LC65 Match case I have loaded 157 times and it is waiting for more. I have 308 rounds with 75 to 90 reloads on them because I use tight chambers. Used to be brass was not expensive, now it pays to have your own reamer made and when you rebarrel rifles have them done with your own reamer so you know what you have.

    You should only use MILSPEC primers loading 223/5.56 to insure primers don't reverse flow into striker opening upon firing.

    M16 for reliable ignition calls for .022" indent on copper cylinders as they are the second hardest primer in the inventory to ignite. The hardest to ignite if Cal 50 BMG. SAAMI recommendations last I saw "recommend" a min indent of .016". Some vendors have a internal policy of .020" indent.


    I have the coppers and the holders to measure striker energy and FAIK I am the only one that does and I can measure 5.56, 308, 30.06 and most magnums. Read my post: https://www.thehighroad.org/index.ph...-cooks.850720/
    Last edited by Humpy70; 12-21-19 at 05:43.

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