338-378

Discussion in 'Reloading' started by jhendri2, Dec 18, 2004.

  1. jhendri2

    jhendri2 Well-Known Member

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    Please share your best loads for the 338-378. Any bullet/powder combo.

    Jim
     
  2. Hired Gun

    Hired Gun Well-Known Member

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  3. alremkin

    alremkin Well-Known Member

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    Thank you for posting that information. The only problem is that they don't list data for for the 300gr SMK, although that can be found on Lilja's site.

    I recent bought a Weatherby Accumark in 338/378 and am slowly putting everything together to be able to shoot it. Here in Canada I currently have a possesion of firearms permit and have to wait to take a course and pass it to get my aquision permit which will take a few months, so I'm looking closely at all the information I can find. I've yet to buy a scope for it, but think I'll go with the Weatherby bases and rings, the Talley Picatinney-Style Rings and Bases, thinking they will be the most solid.
     
  4. Brent

    Brent Well-Known Member

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  5. alremkin

    alremkin Well-Known Member

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    /ubbthreads/images/graemlins/confused.gifHm, I'm not familiar with this. It appears to be some type of computerized Chronograph. Also I can't discern the caliber used. It appears to measure the Muzzle Velocity 13'- 17' from the muzzle and Target Velocity and give the group size as well as pressures which I assume to be chamber pressure. It also seems to calculate the BC for each bullet. Being unfamiliar with this it's hard to guess what some of the rest is like tof2t?... time of flight to target expressed in some fraction of a second? I think I'll go to the main part of that site and see if I can make better sense of this. The only time I've used a chronograph was about 15 years ago it belonged to the rifle club and we set the sky screens 10' from the muzzle with computerization it's reasonable to assume considerable progress has been made... /ubbthreads/images/graemlins/ooo.gif
     
  6. Brent

    Brent Well-Known Member

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    Whoops! This is the link I thought I had posted, sorry bout that.

    Caliber, load etc are listed top of the pic here.

    http://www.hunt101.com/showphoto.php?photo=232156

    It's a screen shot of the test run over Oehler's M43 Personal Ballistic Laboratory.

    http://www.oehler-research.com/model43.html

    TOF2T indeed equals time of flight to target.

    Fist column (Vel13) is velocity measured between the start screen (S1) and the stop screen (S3), at roughly 13'.

    Second column (Prf) is a proof velocity measured between the second start screen (S2) and the same stop screen (S3). The FPS value is expressed as a +- number referenced to the velocity recorded from 4' spaced S1 and S3 screens. The proof chrono has a 2' spacing and is slightly less accurate and simply displays the difference in FPS it measured over or under the FPS reading under Vel13.

    Vel-T = Velocity at target.

    BC = Is the BC calculated from TOF (when using the acoustic target) or two range velocity when another set of screens are set up downrange instead.

    Horz and Vert = shot deviation from absolute center of triangular acoustic target. If your target (POA) is not dead center of the acoustic target, these numbers are meaningless. Group size and radial SD under the target grid are helpfull.

    Peak = Peak pressure, read to the thrird digit.

    Area = Area under the curve

    Rise = Rise time
     
  7. alremkin

    alremkin Well-Known Member

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    I had a look through your photos...nice bull your son shot especially for a first moose /ubbthreads/images/graemlins/cool.gif and the bear your brother and girl friend shot makes me think it's the reason the 50 cal.Barret was invented. /ubbthreads/images/graemlins/shocked.gif

    I noticed your powder for the shot group was H-870 118 gr. Was that your most accurate load with that powder and how hot was it? I ask because I've got 8 lbs of H-870.

    I'm thinking I should get about 2900 fps with the same load out fo my Accumark I had a look at Lilja's site and he got these results with IMR 5010 111.5 gr

    3065 36" barrel
    3056 34"
    3069 32"
    2999 30"
    2982 28"
    2928 26"

    I checked the Sierra site and with these velocities they list these energies at these distances:

    vel ranges 600yds 1000yds

    3000 3520 2369
    2900 3261 2181 energy in ft* lb

    Have you taken any big game with 338/378? I heard that the 300SMK performs well on game, but am concerned because of it's hollow point design how well it hold up at close range. Do you have any insight on this?
     
  8. Brent

    Brent Well-Known Member

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    Yep, nice animals. Sometimes things do work out.

    It's accurate enough not to mess with the load, although I'm sure if he played with it he would probably realize even better accuracy, as he hasn't played with it one bit.

    That's the only powder and OAL combo he's tried.

    I'd consider 3000 fps or a hair more his max load if he wants to get any reasonable brass life out of it. At a certain point the belt will keep on expanding a few ten thou per firing until it is just too tight. Usually they stabilize at .606 OD or so on the first to second firing. If they go .6065 on the next firing, then .607 on the next, usually they will keep going and hit .6075 then .608 and become too tight in just those one or two firings. Generally it's about 65,000 psi that this case is limited to or it just keeps on expanding at the belt. The problem is that you can not size the brass on the belt unless you make a special belt sizing die to use in the first stage. Most beltless cases will let you go to about 68-72,000 psi before experiencing short case life, and it's generally primer pockets that begin to open up rapidly.

    I know he killed a mountain goat at 300 yards with it. Clean through, about 2" diameter exit hole, don't remember the details at this point.