Problem with shot consistancy 30-378

Discussion in 'Long Range Hunting & Shooting' started by s.ferg, Jul 30, 2007.

  1. s.ferg

    s.ferg Active Member

    Nov 8, 2006
    I am attempting to work up a load for my partners 30-378. He has in the past had someone reload 180 gr Ballistic tips but 2 years ago we found that ballistic tips do not work well mule deer as they explode on impact. So I loaded a few accubond 180's and his next trip, had success with Ab's on muleys and an Elk. Well his gun has never grouped smaller than 1.5", so I figured that if I could make my Sendero 300RUm shoot 3 shot groups of .25, I could work up a load for his gun to do the same. Well I worked up a ladder load of h1000 starting at 105 grains(per hodgdon load data) stepping up .5 grain increments to 111 grains. At 107 grains, I could get 2 rounds to shoot .5 then a third would be a flyer out at 1.5". 107.5 would act about the same and 108 would begin to open up. We always start with clean barrel , shoot a fouling shot and then go to work. I can't seem to understand the flyers. I do not know the number of rounds that have been down the tube and I really doubt that the barrel is shot out as it consistantly shoot 1.5 inches. Has anyone else had this simular problem? Any suggestions? Thanks in advance for your replied.
  2. DandT

    DandT Member

    Jul 5, 2007

    My first thought would be possible throat erossion but with you being able to put 2-shots 1/2" apart and then blow the third one out, it makes me wonder. It would help knowing the number of rounds fired down the bore. How does the crown look? Are all raised lands square and sharp? How many rounds are fired at a time before the barrel is allowed time to cool? Have you changed primers or powders and if so, do you still experience the same thing???

    D & T

  3. s.ferg

    s.ferg Active Member

    Nov 8, 2006
    The weatherby has a accubrake. I have no idea how many round have been doen the barrel but it was bought new in '98. If I have to guess about 500 pills. The lands appear square and sharp but I do not have a trained eye. I took it out and shot 3 rounds cold, waiting 5 minutes between shots. Using the same powder and primers. I am going to try some 200 gr partitions before trying some 50BMG powder to see if we get any improvement. My 300 Rum loves 200gr partitions. The ballistic tip ammo in the 30-378 tends to shoot tighter groups than the accubonds. Thats strange because of the BC being nearly the same. Back to the drawing board, scratching my head!
  4. DandT

    DandT Member

    Jul 5, 2007
    Are you able to touch the lands or is the free bore length to great?

    Have you tested the accuracy both with and without the brake?
  5. LewisH

    LewisH Well-Known Member

    May 13, 2007
    1.5" 3-shot group from a Weatherby 30-378 factory rifle is probably as good as it gets. You might consider a custom barrel, or thing to do is consult an accuracy riflesmith.

    At this stage, you're probably wasting your time working up more loads
    Last edited: Jul 30, 2007
  6. alexkeyser

    alexkeyser Well-Known Member

    Feb 22, 2007
    My 30-378 did the same thing every time. factory or hand loads. I brought it to two gun smiths, the last being Bob hart, and after putting a better brake on it and lapping the barrel, truing the action, trigger work, cryoing(spelling?) the barrel, and bedding the action securely, the rifle began to shoot properly as I consider it. It now will shoot 5/8 all day. probably the bedding and cryo treatment had the most to do with it? In my humble opinion the weatherby rifle is not worth the money, only custom for me now. Just ask any of the reputable gun smiths on the site and they will probably give you a list a mile long why they don't like them. Sorry weatherby guys, but this comes from someone who used to love weatherby's. That is until I tried something else! Don't get me wrong I still use, and have my longest kill with a weatherby, I just think the gun should not have required all that work when it cost $1900 when I bought it! No one can deny that most factory rem's can run with any factory weatherby for half the cost. Still, if you have the gun I guess you have to make it work like I did. take it to a reliable gunsmith and let the man do his thing!
  7. James H

    James H Well-Known Member

    Jan 15, 2006
    First check to see if the barrel is touching the forearm. If it is I would freefloat it. I did that to mine before I ever fired a shot and it shoots very well. Mine likes I believe 111 gr Retumbo with both Hornady 180 IB or Barnes 180 TSX, which is a top end load in my gun. If you havn't already make sure everything is tight scope base, rings etc. I would also try a known good scope on it.
  8. Jimm

    Jimm Writers Guild

    Jun 12, 2007
    What Alex

    said ,

    Jim Brown
  9. s.ferg

    s.ferg Active Member

    Nov 8, 2006
    I know most weatherby's have about .50 of free bore, That said the only way to load closer to the lands is to have a custom barrel installed.Weatherby rifles in most calibers have extremely long chamber throats. This freeboring, as it is called, allows the use of powder charges that often exceed the maximum one should use in a rifle of the same caliber but with a more standard chamber throat length. I am going to try a different powder first then try a different bullet.
  10. J E Custom

    J E Custom Well-Known Member

    Jul 29, 2004


    The first 30/378 I had did about the same thing as your,s did
    but no flyers with about a 1" group and factory loads.

    So I decided to rebarrel and hold the headspace to .001 or less
    so that freebore was not a problem.

    I used a #7 tapered barrel 27.3/8" long and was very pleased .

    The two best group,s were with a 120grs of H 50 BMG and a 180gr
    blistic tip at 3431 ft/sec 5 shot group of .134 .
    And 114grs of H 50 BMG and a 200gr noz partition at 3273ft/sec
    and a 5 shot group of .092.

    Over a period of a couple of years I came across a good weatherby
    donor rifle for a future biuld and still having the factory barrel and
    stock I decided to try and make another run at making the accumark

    So I put it all together and head spaced it to less than .001" and went
    to the range , well the headspace helped to reduce group size to .654"
    (not bad for a light barrel) but I wanted more so i tried an old trick for
    heavy magnums with light barrels by installing a adjustable tip pressure
    screw in the front sling swivel an "did it work" I was able to adjust the
    group size down to .259" this using the factory barrel and chamber.

    So before giving up you might try these things in this order.

    Try H 50 BMG ( none of the loads with H 1000 or Retumbo worked for me).

    Try different primers.

    Try 200 gr bullets.

    Try tip perssure (make sure barrel is floated) I know it sounds funny to
    float the barrel and then apply tip pressure but this allow,s the barrel
    to expand but will dampen the harmonics of the light barrel.

    And dont shoot 5 shots back to back (this thing heats up after 2 or 3 shots
    shoot,dry patch and wait 5 min then shoot and repeat process.

    I hope this helps you save the rifle.
    Please let me know how it work's

  11. RMulhern

    RMulhern Well-Known Member

    Jan 2, 2003

    Change the barrel! I'd just as soon try eating a 3 dipper ice cream cone with a turd in the middle as to shoot a barrel with freebore!
  12. Hired Gun

    Hired Gun Well-Known Member

    Apr 21, 2003
    My Accumarks all shoot and have yet to find one that won't go sub moa. H1000, Retumbo and 50BMG are all to slow for a 26" barrel and that case. IMR7828 with Fed 215 primers. 200 grain Accubonds seated as long as will feed from the magazine reliably. The Accubrake is a fine brake but does kick up a bunch of dust if shot prone. I would expect velocity around 3200 to 3250 for this set up.

    To really get it to sing I have found that bedding the action and recoil lug tight will get rid of the fliers. Make sure you are not trying to use windage adjustable scope rings on it. They shift all over on this application. Double dovetails work well. I also prefer my Weatherby triggers adjusted down to around 1 pound. The action must be torqued down with a torque wrench. Hand tight won't cut it. Unbedded they need 65 inch pounds. Bedded I am getting away with 55 inch pounds.

    Make sure you are not resting the front of the rifle where the sling stud is getting into the rest on recoil. A firm but steady hold really helps the groups. I have found it is very sensitive to hold and rest consistancy. I have grabbed up more Weatherby's from people that can't get them to shoot only to run a sub moa group for them right there when they were shooting 3" groups and bad mouthing the brand. 3 shot groups are plenty for evaluation. I never shoot foulers as my cold clean first shots always go right in the groups.

    I use Wipe Out to clean my barrels and do it every time I take it out. My Accumarks all seem to work best with clean barrels.
  13. HoytemanPA

    HoytemanPA Well-Known Member

    Dec 16, 2001
    I also found 200 gr Accubonds able to tolerate the freebore the best of any in my Accumark. Seated so a live round just clears the cutout. Never used the mag so I don't remember if they fit.
    Ditto on the tight bedding/ bedding action Alex and Hired gun mentioned.
    Aluminum bedding block does nothing for it. That was the only change required to fix flyers in my rifle.
    Aside from the deep throat, chamber was nearly perfect.
    Accubrake is a good one.
    Half MOA attainable, factory barrel
    Limit to 3 or 4 shot groups good idea if you want it to last.
    My factory barrel died due to heat and RL25.
    Preferred Retumbo and Fed215GM, but never tried 7828.