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Thread: Casting for semi-auto AR rifles?

  1. #1
    Moderator LuJon's Avatar
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    Default Casting for semi-auto AR rifles?

    Well the zombie bullet thread got me thinking that being able to make bullets from what is readily available would be ideal in the event of any apocalypse. I really like my 6.8SPC and it would be a blast to pump out cheap cast bullets for it. A heavy subsonic round would be cool in a suppressed application so that you don't attract more zombies but the idea on a whole is intriguing to me at any velocity that would reliably cycle the bolt on a regular gas tube AR.

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    Interesting idea.....a 6.8 Whisper.........what does it take to cycle the thing. A gas pulse of about 16,000 psi... What barrel length (short will take slower loads and still cycle) 7", 9" or standard 12" and the right powder burn rate could be made to work. I presume direct gas impingement here) Lead over the gas port could be problematic but gas checks will help. Do you have a mold for the .277" diameter? I'd think the standard 270 weights of 130 to 150 might be the ticket. A generic problem with cast bullets in bottle necks is deep seating and too much un checked bullet hanging into the powder canister, which would be heavy bullets in that small case. A challenging project for sure.
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    You can suppress cast bullet loads but lead buildup along with the normal powder buildup will require you to do a more detailed cleaning more often. I don't see why it would be a problem shooting cast in the 6.8 other than possibly some leading issues that can arise in the AR style rifles small gas tube. I'm not aware of anyone that even make the proper size mold for the 6.8

    I shoot lots of cast in my SKS rifles neither cycling or gas tube leading has been an issue.

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    This is simply not the correct forum to ask this question. You want to go to ar15.com.
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    Moderator LuJon's Avatar
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    Quote Originally Posted by Nitroman View Post
    This is simply not the correct forum to ask this question. You want to go to ar15.com.
    I have a membership there and on 68forums... I like to discuss things like this here because local people I respect are more prevalent here. Casting bullets is an art that I have not endeavored to learn as of yet but there are plenty on this board who have. Tons easier to find a local guy with the equipment and interest in working on a project like this here as opposed to talking with people from texas on those other sites.

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    Finding the proper mold would probably be the worst of your problems as the 270 is not a popular round for using cast bullets. With a heavy for caliber bullet at moderate velocity and gas check it would probably work pretty good. If you went the whisper route and kept the velocity below 1100 using small doses of fast powder, I doubt if you would have much issue with fouling even using a suppressor. Finding a powder that would have enough pressure at the gas port while keeping velocity below supersonic might be a challenge, but I believe it could be done.

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    Finding a mould doesn't appear to be a problem at all. Google kicked back 11,300 results... including, most interestingly, a link to this very thread!

    http://www.google.com/search?hl=en&s...6l0.3.5.2l10l0

    Now, are you thinking about using a silver nitrite mix in these boolits to cover the werewolf thing? I'd think that hard cast might alleviate the leading problem.
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    I'd think that hard cast might alleviate the leading problem.
    Sometimes it does sometimes not,the AR style rifle are a bit more prone to lead buildup stoppage due to there small gas ports and gas tube unlike SKS and AK rifles which have much larger gas ports and use gas tube pistol cycling systems.

    Even very hard cast lead want be as hard as copper jacket bullets and depending on the roughness of the gas port hole it may or may not scrape lead off the bullet as it passes by which will have a big influence on leading. A gas check bullet is definitely in order as well asexperimentation with different powders to find you best load to suit your needs.

    It's definitely going to be a project but doable. You will find this thread helpful http://castboolits.gunloads.com/showthread.php?t=39802

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    Unless you want to have a custom mold made( there are some very fine custom mold makers) it can be difficult to find the right mold for a particular caliber, in the right weight and the right bullet shape for odd calibers despite what google says. For casting the .277 or better yet a .278 or .279 is not a real popular size. If you go the custom route, you can get anything you want but you can plan on paying $200/$300 for a one off custom mold.

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