New "Long Range" Cartrige Design" 10,3mm Sniper-Tactical

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Black Diamond 408, May 10, 2006.

  1. Black Diamond 408

    Black Diamond 408 Well-Known Member

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    New \"Long Range\" Cartrige Design\" 10,3mm Sniper-Tactical

    About 10 years ago i built my first 50BMG rifle, although it was a riot to shoot, i was intriqued by the BMG case. I have seen lots of wildcats over the years on the big 50 case, seems they just didnt take off due to the fact of just too much case capacity. I was allways going to shorten one up and design a shorter version. Seems the whole project just got lost in my note book. I found my old plans several weeks ago and re-started the idea. Since my first thoughts on this i have been designing and building actions so that part is simple now. Next item was what Cal.? Back then, not much for high BC bullets and i didn't want a 50 cal. I was thinking of something in the 40 cal range, I feel the 338 is just too overbore in this large case. Then came along the .408cal bullets, now there are choices and more on the way in high BC projectiles. This sparked my interest in the project again. I had started to make form dies to shorten the BMG cases but found that the military allready has one called the 50 Spotter case. It is 3" long, perfect for what i had in mind, H2o capacity is 200grns on a military case. I procured some to work with and see what can be done with the little sticks of dynamite! After several hours on the Auto-Cad program redrawing the case to a more prefered dimension, i have come up with a great looking new cartrige.

    Here are some of the specs:
    .800 base dia.
    .731 shouler dia
    Base to shoulder 2.350", moved foward .300"
    Base to neck 2.550
    Neck dia. .443 od.
    Neck dia. .405 id.
    Overall case length 3.00"
    Shoulder angle 37 deg.
    The case taper was not changed from Military specs. This case will extract very easy even in high pressure loads. 55,000# to 63,000# will be the usefull range for the BMG case. With the 400 or 419grn bullets, estimated speeds are 3300fps, that will give just over 10,000# of muzzle energy.
    500yd sight in: +14moa will =1000yd hit. +45moa= 2000yds
    These are early estimates.

    The new case design resembles a WSM short mag case on steriods!

    This will only work in a BMG type action due to the large case head dia. I have designed a short BMG action just for this case, 1.900"diax 10.5" long...single shot or repeater.
    Two lug bolt similar to a rem 700 action. My test rifle will have a 1 x13 twist bbl 32" long. I should have test results sometime this summer.
    [image][​IMG][/image]

    This is the 10,3mm Sniper-Tactical with 419grn bullet.

    [image][​IMG][/image]

    Here is a comparison with a Pepsi can.
     
  2. Michael Eichele

    Michael Eichele Well-Known Member

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    Re: New \"Long Range\" Cartrige Design\" 10,3mm Sniper-Tactical

    looks interesting................
     

  3. lerch

    lerch <strong>SPONSOR</strong>

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    Re: New \"Long Range\" Cartrige Design\" 10,3mm Sniper-Tactical

    Looks pretty mean 408!!!! I am ready to see what this puppy does!!

    steve
     
  4. 1doug

    1doug Well-Known Member

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    Re: New \"Long Range\" Cartrige Design\" 10,3mm Sniper-Tactical

    dave,

    whats up with all the lime? LIme pepsi, lime background?

    Looks like you should get 3600 or better with the 419.


    d-a
     
  5. Black Diamond 408

    Black Diamond 408 Well-Known Member

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    Re: New \"Long Range\" Cartrige Design\" 10,3mm Sniper-Tactical

    d-a

    I dont know if it will do 3600 or not, i will be very happy with 3400. Dont want to ruin the cases! They (BMG cases) will take 65,000#psi before things go to crap. I dont want to have to resize with a cheater bar on the press! The rifle will prolly weigh in around 20-25# It may have a ABS carbon bbl on it, i have been talking with Mike Rock and Mike Degerness about the project.

    Dave
     
  6. davewilson

    davewilson Well-Known Member

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    Re: New \"Long Range\" Cartrige Design\" 10,3mm Sniper-Tactical

    BD, now that is a sweet looking LR cartridge. is that a lost river bullet in that thing? who makes decent bullets for the 408? please build a light weight version first as you can always add weight if it kills ya!
     
  7. Black Diamond 408

    Black Diamond 408 Well-Known Member

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    Re: New \"Long Range\" Cartrige Design\" 10,3mm Sniper-Tactical

    Dave,

    Yes that one has a LRB J-40 419grn bullet, they do shoot pretty good. TTI Armory has a similar line of 408 bullets, 305gr, 400grn and a 419grn. I have tested their 419grn and they shoot very good! Just a little differnt ogive and material is some sort of brass instead of cupper-nickel that lost river is using. I cant emagine what the 305grn would do out of this caliber(4000+?) It is pretty much point blank to 1000yds in the 408C-T guns @ 3500fps. Richard from Wildcat bullets is waiting for his 408 dies to make his famous jacketed bullets. A 400 or 450grn Wildcat would be real impressive in this new case. I will be testing them all when the little darlin is built.

    I have shot 408C-T with the 419 bullets just over 3000fps, the recoil was about moderate to heavy, the gun was light and not much of a brake.
    There should be plenty of muzzle blast to make a muzzle brake work very well. I like light guns, most all of my customers are hunters and want carry stuff. This will still be on the heavy side no matter what. The bbl will need a 1.700 shank then it can taper to whatever a person wants, im looking at a 1.700" shank 3" long, taper to 1.625 for another4" then it will step down to 1.200 and taper out to 1" at the muzzle, 32" long. At least 10# of metal here. Unless a carbon bbl is used, then it will be 1.700 with a M24 contour to 1.300" at muzzle. Real stiff bbl and lighter. Just takes $$$$

    Dave
     
  8. Brent-AR-30-338

    Brent-AR-30-338 Well-Known Member

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    Re: New \"Long Range\" Cartrige Design\" 10,3mm Sniper-Tactical

    A .416 Barrett AI... /ubbthreads/images/graemlins/cool.gif
    should be fun. waiting for range report. /ubbthreads/images/graemlins/grin.gif
     
  9. davewilson

    davewilson Well-Known Member

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    Re: New \"Long Range\" Cartrige Design\" 10,3mm Sniper-Tactical

    i think you should just call this thing the 40-shorty. it has 2mi. plus written all over it.i'd put a holland QD style brake, made about 2.5" in dia on and this thing could be shot with a 15 # gun.i wish i could build one.if you give me one of those actions,and do the gunsmithing for free,i'll test it for ya, no charge...honest!
     
  10. Black Diamond 408

    Black Diamond 408 Well-Known Member

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    Re: New \"Long Range\" Cartrige Design\" 10,3mm Sniper-Tactical

    Dave:

    Yeah two miles, i cant hardly see 1K It will be fun to shoot however, 15# dont think that will happen even with a Ti reciever and carbon bbl. Fly out here and you can be the first one to test her! Mid summer if all goes well.

    I forgot to add this to the specs: loaded round 4.300"

    Dave
     
  11. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Re: New \"Long Range\" Cartrige Design\" 10,3mm Sniper-Tactical

    BD408,

    Is that an actual fireformed round or is a lathe turned dummy round? Looks like lathe turned, far to clean for any 50 spotter case I have every seen!!!

    Looks good.

    Kirby Allen(50)
     
  12. Black Diamond 408

    Black Diamond 408 Well-Known Member

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    Re: New \"Long Range\" Cartrige Design\" 10,3mm Sniper-Tactical

    kirby,
    Yeah that is a lathe turned round from my chamber dimensions. I have 10 rounds ready to fire form, just no chamber to shoot them in. But i am working on that problem! I just wanted to make sure everything looked good and the specs worked before i ordered the reamers. I am going to have Kiff make the chamber and sizer die reamers.

    Dave