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257 Blackjack

coldboremiracle

Freelance Sharpshooter
Full Member
Minuteman
  • Jul 7, 2009
    5,224
    1,108
    Utah, north
    www.coldboremiracle.com
    My latest project, the 257 Blackjack. A SAUM based cartridge shortened to run in a SA DBM, pushing the 131 gr Ace at 3200 fps with a BC of .340-.345. supersonic past 2000 yards and only 5.3 MRAD to 1k.

    Built on a 700SA, Iota Carbon chassis, Proof 24" 7.5tw, US Optics TS 20, PVA Jetblast brake, A TT Diamond, and Hawkins bottom metal.



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    Never heard of this caliber before, but definitely looking forward to the ballistics on this.
     
    I shoot in 25-06. Anything .257 is a hammer. Blackjack is the company. Sierra is the manufacturer.
     
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    So interested in going with one of these quarter bore cartridges to utilize this awesome 131 ace bullet. What's the story with the 25 SAW compared to the 25 creed and 25x47? Advantages, disadvantages, etc. thanks
     
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    So interested in going with one of these quarter bore cartridges to utilize this awesome 131 ace bullet. What's the story with the 25 SAW compared to the 25 creed and 25x47? Advantages, disadvantages, etc. thanks
    Not real familiar with the SAW, but its velocity is only slightly ahead of my 25CM. This 257 BJ is a solid 200-250fps ahead, and flat enough to beat most things close to it in other calibers.
     
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    I have a 6.5 SST. It runs really well out of binderless AI mags. Opened up the bolt face on a T3. Loaded OAL with a 147 is 2.910", 10 thou jump. Mags allow 2.980". I can do 3075 before I get pressure.
    What’s the powder and charge weight?

    I believe it is a bit shorter. Runs great from AI mags and a SA.

    What’s the 25 BJ OAL?
     
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    56.3gr H1000 but I'm downloading it to 55.5gr now to keep it at 3000
    Thanks. Heard of that case, but o ow nothing about it. I’m tinkering with a 25 PRC on and off. Just haven’t had the time to do much with it lately. It’s right in that same ballpark with h1000 and the 131.
     
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    looks like 51-55 grains of any slow magnum powder is where its at (h1000, RL25-26, Retumbo, H4831).


    That's impressive. 25-06 performance with a touch less powder using a short action.

    I may need one now.

    Hopefully it doesn't torch barrels like the 25wssm did.
     
    Depends on how hot this is running, if its anything like the 6.5 SAUM, You can get pretty decent barrel life out of it. Say 2k or a little better.

    Scott

    My 6.5 SAUM opened up at 1200 rounds. Throat was pretty torched. Ran 60.6gr h1000 with 140s. Could have still worked for hunting but probably not the best for matches.
     
    I think barrel life is = (powder/case capacity) X Rate of fire. no gettin around it.
    Yes, the most dominant factor for barrel erosion is the thermal energy released by the powder, which is also the energy that propels the bullet. No free lunch there.

    There are smaller factors influencing throat erosion related to the specific flow of gases creating hot spots according to the laws of fluid dynamics. If you look at Mach diamonds for example, you realize that there are significant pressure and temperature variations in high velocity flow scenarios. That is the reason why some cartridges burn barrels faster that other cartridges of similar powder volume for the same caliber.

    In a far out analogy, you can tweak a couple more miles per gallon out of a big block V8 with tuning but you will always burn more gas than a Prius.
     
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    My latest project, the 257 Blackjack. A SAUM based cartridge shortened to run in a SA DBM, pushing the 131 gr Ace at 3200 fps with a BC of .340-.345. supersonic past 2000 yards and only 5.3 MRAD to 1k.

    Built on a 700SA, Iota Carbon chassis, Proof 24" 7.5tw, US Optics TS 20, PVA Jetblast brake, A TT Diamond, and Hawkins bottom metal.



    View attachment 7220468View attachment 7220470
    Any new updates?
     
    3270 and room for more? Keep the info coming. Really interesting cartridge
     
    Wondering the same. Any field experience with these? Elk specifically.
     
    Have you seen a meaningful bump in speed in the 26" or 28" barrels? Is there any difference between this and a 25 SAUM? Love those numbers...
     
    Last year, using my 25CM T3, we took three deer, and two elk.
    600yd
    s
    1564298D-3159-49CD-9247-73F1B64A46CC.jpeg


    This one was at 500ish IIRC

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    Junior put the hurt on him real good

    This one I took up close, probably my closest kill in 4-5 years. 250ish
    4F5180FD-32B2-4A94-9910-7AB571D1EC83.jpeg

    The elk we killed were both at 300 yards, we neck shot them.


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    D5DC5683-805A-41A8-A521-C32B856A0BD5.jpeg
     
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    All of them were killed with the same load, 131 ace shot from 2950 from my 22” T3. Every one of them was damaged acutely, impressive wound channels. The last two deer there, the puny guy was at 1100, bullet entered between his neck and his left shoulder, the exit is seen on right flank. The bigger dude below him, was at 420, the shot was almost exactly opposite, entered the right flank, exited between his neck and left shoulder. Both went almost immediately down, less than 20 yds.
     
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    I'd love to have a 25 cal short mag of some flavoring, but don't like 24"+ barrels. I did some looking around and didn't see a cf barrel manufacturer with anything less than 24". Does anyone know if Proof, Paradigm, Carbon Six are planning on make 25 cal 1:7 ish barrels in the 20" range?
     
    Very interesting CBM.....I'm having a 25 creedmoor barrel being made now for my DT. I have another project rifle waiting to be finished.....may have to look into a 257 BlackJack.
     
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    Reactions: coldboremiracle
    I'd love to have a 25 cal short mag of some flavoring, but don't like 24"+ barrels. I did some looking around and didn't see a cf barrel manufacturer with anything less than 24". Does anyone know if Proof, Paradigm, Carbon Six are planning on make 25 cal 1:7 ish barrels in the 20" range?
    Hells Canyon Armory (Benchmark blank)
     
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    I happened across the data for the 25 wsm my Dad built years ago.

    He ended up pushing 100grn bullets 35-3600 fps, 64 grns IMR 7828.

    115's he ended up at 65 grns retumbo to push 3400fps.

    Needless to say that barrel came off at 1200 rounds missing 5" of rifling.


    I would say 1200-1500 rounds out of a 257 blackjack is a reasonable expectation.
     
    I shoot in 25-06. Anything .257 is a hammer. Blackjack is the company. Sierra is the manufacturer.

    Okay, for 25-06 we needs to be at least partial FL sizing. Don't be neck sizing. It will shoot lights out but you will be running into some drifting zero and small accuracy issues. Those sort of well that was different shit, lol. Reloads like a 300 H&H for us Africa operators.
     
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    I happened across the data for the 25 wsm my Dad built years ago.

    He ended up pushing 100grn bullets 35-3600 fps, 64 grns IMR 7828.

    115's he ended up at 65 grns retumbo to push 3400fps.

    Needless to say that barrel came off at 1200 rounds missing 5" of rifling.


    I would say 1200-1500 rounds out of a 257 blackjack is a reasonable expectation.


    Ouch, Its not meant for a poor man I guess. Completely stupid question but how much is brass running for it? What kind of life does it get?
     
    Sorry if I missed it, but Is there plans for brass to become available
     
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