168 bergers in 7mm mag

Discussion in 'Reloading' started by retiredcpo, Mar 22, 2010.

  1. retiredcpo

    retiredcpo Well-Known Member

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    ok help me out here.
    I have never been a big fan of the bergers because everyone I know who has used them has had problems with them
    But with my new sendero I wanted to keep and open mind and try them.
    loaded up several with differant lenghts and powder combos ect, and headed out
    nothing shot better then my accubond load.
    then I shot a group with 63 gr of 4831sc 20 thou from the lands slighly larger than one hole. No way I thought so I shot another group, One hole:D
    i loaded 40 more and back out to the desert. Shot great out to 500 yards.
    Compared my drop numbers to BC program and come up around 2750 fps
    I really like to be faster than that.
    My problem I have is allmost every load I see people here using is over max according to the chart berger sent me.
    Are there alot of people running excessivly hot lots or is bergers chart conservative?
     
  2. MSLRHunter

    MSLRHunter Well-Known Member

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    Did you check that velocity with a chronograph? I have never used that powder, but in my 7mmRemMag with 64.5 grains of RL22 I get about2920 and my father in law gets about 2950 out of his sendero with that same load. So I do think bergers load data is fairly conservative, my load mentioned here is just slightly over max, but with no pressure signs.
     
  3. phorwath

    phorwath Well-Known Member

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    Yeah, I think the Berger data is very conservative. Low pressure side of safe.
     
  4. barkley

    barkley Member

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    I use 71 grains of retumbo in my 7 mm and it shoots great groups. Thats the max load according to my sierra manual with velocity around 3000 fps. I just have got my chronograph and have not had time to shoot threw it yet but will in a couple of days. I have shot 3 deer with this load and berger bullets and it drops them like a ton of bricks
     
  5. kiwi3006

    kiwi3006 Well-Known Member

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  6. ovastafford

    ovastafford Well-Known Member

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    I think its really conservative. The max for retumbo and the bergers is 70.4grs. Iv run up to 75grs and no pressure signs, my best accuracy load is at 70.7 grs though. Good Luck!
     
  7. phorwath

    phorwath Well-Known Member

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    I load 74.6 grains Retumbo with a Federal 210 primer and chronograph MV of 3050 fps. Accuracy is good. Bullets jammed into the lands about 0.010". Barrel length is 24 3/8".
     
    Last edited: Mar 24, 2010
  8. roninflag

    roninflag Well-Known Member

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    some of the loads i have seen ( the best of the west load) seemed quite warm. i shot a big rocky mtn bighorn with a 168 and 63.1 of re-19. 2920 . less than 1/2 inch groups. my sendero has a kreiger barrel. i tried various 140 grainers for the rmbh hunt . the 168's out shot them. i shoot have shot from 59 to 63.1 grain of 19. with re-22 and h-4831 you should safely get to 2900. h-4831 ( long cut ) is another i have had good result out of the 7mm mag. have not had time to try h-4831sc. the 215gm gave higher velocity and es than the other mag primers. your 2750 load fine for deer and antelope. for elk i would choose a different bullet . the 168 did not exit the rmbh. which is exactly what i wanted .
     
  9. retiredcpo

    retiredcpo Well-Known Member

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    I did not use a chrono(dont have one) I used the balstic calculator on the best of the west web site I kept changing the Velocity inout untill it matched my drop numbers out to 500 yards.
    Im going to try increasing the load up to the max and see what happens
    if the groups stay the same and no signs of pressure ill change if not Ill go back to what i had
     
  10. Fitch

    Fitch Well-Known Member

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    Just for fun I modeled that in quickload. Following publisher's assumptions about start pressure with the bullet jammed into the lands, I get 3,099 fps (pretty close to your measured 3050) and 68,700 psi with a 24/38" barrel. Pretty stiff but probably won't disassemble anything.

    Fitch
     
  11. phorwath

    phorwath Well-Known Member

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    Interesting. That QuickLoad software, even though I don't own it, continues to impress me. I've chronographed this load over a dual chronograph setup quite a number of times, and am pretty confident in the 3050 fps MV.

    I'm using Federal brass and the primer pockets are long-lived, so I figured the pressures couldn't be too outrageous. I can't go much higher though or the cases and the rifle start to complain. This load is considered a maximum load in my Tikka T3, and may be over-maximum in other rifles.
     
  12. Fitch

    Fitch Well-Known Member

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    Your description of it being sort of on the line for the cases and rifle about what I'd expect based on the model. I used Federal brass at the water grain capacity it has in my Ruger (84.4) when I modeled it.

    I'm reading everything I can find related to the 168g Berger in 7-mags. My new one will be here in a week or 10 days. So will the bullets. The Ruger has a 24" barrel, the new Savage has 26". The chambers will be different so I'll have to segregate the brass. I'm working up a 160g Accubond load for the Ruger. I'll shoot the Bergers in the Savage BVSS.

    Fitch
     
  13. phorwath

    phorwath Well-Known Member

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    In case your interested: My 160gr Accubond load for the same rifle is 67.6 gr IMR 7828SSC, CCI 250 primers, bullet seated 0.020 off the lands. MV = 3045 fps. This is the load that I selected for hunting and it provided good accuracy.

    During 160 Accubond load workup & experimentation, I also chronographed the following data.

    68.2 gr IMR 7828SSC gave me MV=3065 fps. Average of 3 shots @ 45F.

    68.9 gr IMR 7828 gave me MV=3084 fps. Average of 5 shots @ 32F.
    68.4 gr IMR 7828 gave me MV=3060 fps. Average of 5 shots @ 32F.

    70.2 gr RL25 gave MV=3087 fps. Single shot. Snug bolt lift @ 38F.
    70.8 gr RL25 gave MV=3135 fps. Single shot. This load was too hot @ 38F.
    Both of these RL25 loads were overpressured in my rifle.
     
  14. Fitch

    Fitch Well-Known Member

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    Thankyouverymuch!

    I'll load some of those as the max in a work up from about 1.5g low - I happen to have some of that powder. That looks like a very good load. Models at 3012 fps in the Ruger's 24" barrel, 57,861 psi. A guy can shoot a load like that all day, not hurt anything, and put the meat in the freezer.

    The ballistics look good for that bullet as well. +/- 3" PBR of 303 yards (using the G1 BC) when sighted in at 258 yards (2.3" high at 200). Sighted in at 200 yards, the VX-II with hold over dots would have dots at 309 yards, 419 yards, and 532 yards. I can work with that.

    QuickLOAD frequently does a good job 2with IMR powders, espeicallly in large cases (.308 size and up).

    If I set the temperature to 45F in QL the SSC load models at 2998 fps. The two 7828 loads model at 3009 and 2986 respectively with the temperature set to 32F. They are all within 2.5% which is pretty good for an internal ballistic model.

    QuickLOAD doesn't model RL25 as accurately as it does 7828. It predicts 3000 fps at a very reasonable 55,580 psi for the 70.8g load - that's still within 5% on MV (4.3%) but it's a good example of why one backs off 10% and works up using the chronograph to make sure nothing is off the reservation.

    Thank you very much for the range data. Much appreciated.

    I'm going to go to the reloading bench a few feet behind me and load up some 7828SSC loads to see how they do.

    Fitch