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Thread: Cutting 5.56 Blanks

  1. #1
    Boolit Master
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    Cutting 5.56 Blanks

    I have begun setting aside money for one of BT's 30 caliber swage sets. When I have enough saved up, I intend to get the tools to make 180 grain .312" jackets from 5.56 brass. I have around 100 lbs of fired blanks set aside for this project.

    Does anyone have an idea what length to cut the brass at for this project?
    I am just trying to get a jump one of the less enjoyable steps, prior to getting the dies.

    Thanks

  2. #2
    Boolit Master
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    Different manufacturers of cases have different internal geometries, and you'll end up with different weights. With this being 5.56 brass the internal geometry with tolerances is usually more controlled by prints issued by the DOD, unlike SAAMI where the internal geometries is pretty much left up to the individual manufacturer. Might sounds like a round about way of saying it, but the cut length for person A may not be right for Person B because of these differences. Further more blanks can often be a way for manufacturers to use cases that are not up to the DOD spec, this obviously further muddies the water.

    All of this is to say, you're going to have to figure out what case length is appropriate for your bullet by trial and error. I'd start but cutting the case just behind the shoulder, and then weight it, subtract the weight of the case from your total bullet weight. The remainder should tell you the ideal core weight. If you know the density of the lead and the diameter core you intend to use, you should be able to calculate the core length. BT Sniper should be able to tell you how long the jackets his dies will accept and how long/short the cores can be. From there you need to find the balance between jacket length and core length.

    There are infinite combinations of jacket length's and core lengths that will work, but it will likely take a few runs to figure out what works best for you.

  3. #3
    Boolit Master
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    Thank you.
    Your answer makes a lot of sense.
    If I cut just below the crimp, and later at a point further down the casing, would anyone here have a use for 1/2 - 3/4" sections of casing cut from the center?
    I would hate to take something to the scrapper which could be used by another swager.

  4. #4
    Boolit Master PWS's Avatar
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    I've found the drawn length to vary slightly from the cut lengths so that is, unfortunately, another factor in determining the cut length. Usually they're close but the drawn case is longer than just the cut case.

    I'm also casting my cores and using them sorted from the mold and they too do not match the length of the cavity in the core mold.

    None of this is insurmountable, it just takes some playing around with sizes and be sure to take notes while doing so!

  5. #5
    Boolit Master
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    When I cast my cores, I don't anticipate them to be the exact length or weight. I always cast a few grains heavy. The purpose of the core swage die is to bring the core to it's final dimensions and bleed off any excess lead.

    Yes, when you draw the case down in size it will grow in length. When ever I do a draw down operation I always expect that I will need to do a final trim to square up the end and trim to final length.

  6. #6
    Boolit Master PWS's Avatar
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    Don't know if it'll help the OP but this is how I'm cutting my cases. Works well enough to get them all within +/- .002" and usually better.

    http://castboolits.gunloads.com/show...es-for-jackets


    Oh! and I'm too lazy to make a core swage die so I just cast up a big bunch and sort them by weight.

  7. #7
    Boolit Master



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    Grullaguy,


    PM sent

  8. #8
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    I'll have to check and see if I got some data on the before and after 223 draw.

    If you cut the neck off the 223 first then make your cut we can use it to make 9mm/357 bullets. I know it is an extra cut on your part but that is what it would take to make a useful piece of brass jacket for us. Then yes I would certainly be interested or know of those that should be.

    Check out a thread on making 9mm and 30 cal bullets from 223

    http://castboolits.gunloads.com/show...p-223rem-brass!
    When you stop learning you are dying.

    Check out available BTSniper products and prices at
    http://castboolits.gunloads.com/foru...?114-BT-Sniper

    Say hello and like my FB page as well.
    https://www.facebook.com/bt.sniper/

    Good shooting and swage on!

    Brian

  9. #9
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    BT Sniper's Avatar
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    That thread actually has some before and after data. Seems like 1" became 1.25"
    When you stop learning you are dying.

    Check out available BTSniper products and prices at
    http://castboolits.gunloads.com/foru...?114-BT-Sniper

    Say hello and like my FB page as well.
    https://www.facebook.com/bt.sniper/

    Good shooting and swage on!

    Brian

  10. #10
    Boolit Master
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    Thanks Brian. I have been reading that thread too much in the recent past, then I would get excited,...then I couldn't sleep. I have been trying to talk myself out of your dies for years, but I had to admit to myself that swaging is just something I need to do.

  11. #11
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    BT Sniper's Avatar
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    Welcome. I've been there too with the excitement over new ideas and unable to sleep.

    Swage on!
    When you stop learning you are dying.

    Check out available BTSniper products and prices at
    http://castboolits.gunloads.com/foru...?114-BT-Sniper

    Say hello and like my FB page as well.
    https://www.facebook.com/bt.sniper/

    Good shooting and swage on!

    Brian

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check