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Thread: Need some outa'-the-box thinkers...

  1. #1
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    Need some outa'-the-box thinkers...

    For several years I've been playing with a subsonic hunting round, the only real one I know of. A round that will ethically carry elk-killing energy to 500+yds, silently.

    I've tried 5 different magnum cf rifle cases cut down to push 750-900gr bullets at 1050fps. I've run out of case with the blown out 460Wby.

    It recoils so hard I'ma knock an eye out.

    I've tried everything I know of and am now working on making A BIGGER CASE WITH MORE POWDER because I need to increase the muzzle blast without increasing the velocity.

    I need some help on how to make a less efficient case. Hopefully without going clear up to the BMG case.

    I'm right now shopping for bolt actioned shotguns as my next build will be with either the 50-140 Sharps or a brass shotgun case for more capacity.

    I need MORE POWDER, but LESS VELOCITY. I've already built The World's Largest Muzzle Brake (over 24sqin impact area... It'll stop a 50BMG so's you can shoot it off your FACE) all's I need is enough gas to make it work, to pull the bleedin' gun off me......expressed as a 10-12lb gun it's got around 70fp recoil energy IIRC, I'd like to yank off over half of that, preferably 2/3 (I kinda' like to stay under 20fp!) and I need wind to do that...

    any ideas?


    (So far Boyd's had the best idea......."make a double-barrel with one barrel shooting a blank, and hook the triggers together".....So I know he understands the problem at least!)

  2. #2
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    RPP rocket propelled projectile ie tiny bazooka

  3. #3
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    Nothing in that continuing post on big bore stuff, the one that's about 100 pages long now - well maybe 21?

    http://benchrest.com/showthread.php?...h-700he/page21

  4. #4
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    The great Elmer Kieth was an advocate for slow and heavy, as apposed to fast and light.

  5. #5
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    fergitaboutit! James
    Last edited by JDMock; 01-15-2017 at 12:11 PM.

  6. #6
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    .50 Alaskan loaded with a 750 gr A-Max? I built one on a Siamese Mauser and am using a 585 cast LFN. Very easy to load anywhere from 850 to 1,950 fps. With the right powder I suspect you could get to your goal.

    -Lee
    www.singleactions.com

  7. #7
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    All else being equal, a larger bore will increase efficiency and require faster powders. Have you tried necking down and using a smaller bore or are you locked in on bullets and caliber?

    edit: as Boyd says in a later post, my point is that necking down and using a smaller caliber, but the same case and bullet weight, will work better with considerably slower powders. Of course, that can translate to higher muzzle pressures. He makes a good point about shorter barrels, too. Again...all else being equal.

    I think the biggest wall you'll hit in doing what it sounds like you want to achieve is physics. As you probably know, a brake can only do so much. They work best with small caliber, high pressure rounds...just the opposite of what you're doing, from what I understand.
    Last edited by mwezell; 01-11-2017 at 04:48 PM.

  8. #8
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    CAN YOU be sonic on the first 200 yds and then go sub ?
    or are you worried about the transition ?
    suppressor with internal brake ?

  9. #9
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    Al, that suggestion must have been made when I was in complete out of the box mode. I take it that you want more working pressure in the brake to make it more effective, higher pressure at the muzzle. How about making the barrel shorter, testing in stages. If it looks like it will work, but you end up with a legality of barrel length issue, then you can devise some sort of permanent attachment for the brake, and possibly an extension beyond it, also permanently attached. This would make cleaning a bit of a pain, but since the purpose is for hunting big game, I think that you should not be shooting that many rounds, after your configuration has been finalized. The point about using a smaller caliber, bottle necked case, and slower powder could be combined as well.

    A couple or three decades back, a friend had a .338-.378 KT built. At the time he was shooting 112 grains or so of H870 behind a 250 grain bullet, mercury recoil reducer, Decelerator pad, good sized radial muzzle brake. The muzzle blast was formitable, not as much for the shooter, but outside of the cone, on a firing line that had 8" of steel roof in front of the bench with matching concrete floor, it was ....abusive for anyone in the area without double protection, and frankly that was not really enough. Jumping forward to more recent times, he is shooting less of a faster powder, and the blast is noticably less.

    If you mixed some slow powder in with the fast, would you get more blast, without more velocity, without more pressure, more powder on the snow?

    There I go again, waaay out of the box. Have fun. Better your shoulder than mine.

  10. #10
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    A secondary charge at the brake or a tube(s) redirecting the gas to the brake from an appropriate place along the barrel.
    Last edited by Rflshootr; 01-11-2017 at 12:52 PM.

  11. #11
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    Probably should have made another post but edited my previous post instead. Boyd makes a good point. Smart guy, that Boyd feller'.

  12. #12
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    Quote Originally Posted by Boyd Allen View Post
    Al, that suggestion must have been made when I was in complete out of the box mode. I take it that you want more working pressure in the brake to make it more effective, higher pressure at the muzzle. How about making the barrel shorter, testing in stages. If it looks like it will work, but you end up with a legality of barrel length issue, then you can devise some sort of permanent attachment for the brake, and possibly an extension beyond it, also permanently attached. This would make cleaning a bit of a pain, but since the purpose is for hunting big game, I think that you should not be shooting that many rounds, after your configuration has been finalized.
    .

    Ohh Man, you're fast.....

    This is actually where I am currently, down to an 11" barrel with a welded extension. I don't dare go shorter as accuracy is tumbling off.

  13. #13
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    BTW, my limiting factors are energy (I consider 1500ftlb to be adequate with a large bullet) and velocity (suppressed). And the fact I want the rifle to be packable. (I can easily accomplish "energy" and "packable" in a variety of platforms up to 50BMG but the "quiet" part makes it difficult)

    The SMALLEST bullet which meets these goals is 750gr.

    The problem with Ed Hubel's work is that he's not constrained by these things.

    It's like "ya got 3 things......"Energy" - "Weight" - "Velocity" ....... pick TWO!"

    For instance, the things AWESOME at 18lb......but who wants to pack a donkey thru the woods?

  14. #14
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    Quote Originally Posted by Rflshootr View Post
    .....redirecting the gas to the brake from an appropriate place along the barrel.
    I hadn't thought of that....thanks.

  15. #15
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    Quote Originally Posted by Lee Martin View Post
    .50 Alaskan loaded with a 750 gr A-Max? I built one on a Siamese Mauser and am using a 585 cast LFN. Very easy to load anywhere from 850 to 1,950 fps. With the right powder I suspect you could get to your goal.

    -Lee
    www.singleactions.com
    IME the recoil starts to really get rough at around the 700gr mark and just climbs like a steamdrill up to 900 grains...

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