708 urgent help

Discussion in 'Reloading' started by gr1ffer, May 17, 2012.

  1. gr1ffer

    gr1ffer Member

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    I need help with my 7mm08 I got it custom built and am really struggling to find a suitable load. I only want a velocity of 2800 fps with a 140 grain accubond I've tried a bunch of different components and powders and keep coming up at around 2650 fps on max book loads even RL-17 gives 2650 fps. I don't know if it's my load or chrono but am losing confidence to the point were I'm considering getting rid of it.
    Any ideas please help
     
  2. gillettehunter

    gillettehunter Well-Known Member

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  3. EXPRESS

    EXPRESS Well-Known Member

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    I had the same problem with my 7mm-08, could not break the 2800fps mark, but then again it was only a 22" barrel. With Federal light magnum factory loads it got well over 2800, close to 3K if I remember correctly.

    I ended up rebarrelling the 708 to a 6.5-284, hich in terms of energy has no real gains, but because you are shoot a 6.5gn 140gn bullet, it has a much better BC and SD so you end up with better performance.
     
  4. jimbires

    jimbires Well-Known Member

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    something doesn't sound right to me . I'm guessing chrony troubles .
    I have two rifles in 7-08 . one with a 24 inch broughton bbl . I shoot Berger 140 VLD hunting . I use RL17 powder , and a CCI 200 primer . here is my chrony readings outside temp 75*F .


    44.0 gr .....2781FPs
    44.5 gr .....2788FPS
    45.0 gr .....2829FPS
    45.5 gr .....2853FPS
    46.0 gr .....2891FPS
    46.5 gr .....2924FPS
    47.0 gr .....2966 FPS
    47.5 gr .....3005 FPS
    48.0 gr .....3054 FPS ( quickload max )
    48.5gr .....3106 FPS
    49.0 gr ..... error

    different day 65*F
    49.0gr .....3077,3077,3080,3077,3081

    different day 80*F
    stock Tikka 22inch bbl using Hornady 139 BTSP bullets , CCI 200 primer , IMR4064 powder

    43.2 gr , 2821 , 2800 , 2805 , 2794 , 2790 ,
     
  5. arroyobuck

    arroyobuck Member

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    I don't think it is the chrony. I have found that I can only get 2650-2675 FPS out of my 7-08 mountain rifle when using ABs. That is with 42 grains of Varget, which is the max book load (according to Nosler). However, 139 Interlocks (spitzers/flat base) with 41.5 grains hit 2800+ FPS. For some reason the ABs are "slower" in the 22 inch MR barrel.

    Other velocities I have personally seen are:

    Remington Core Lokt 140 grain factory loads - 2770
    Hornady Superperformance 139 gn SSTs - 2886


    Try some factory Hornady superperformance SSTs. You may find it's not worth reloading...
     
  6. str8shoot

    str8shoot Well-Known Member

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    I get a 140 accubond going right at 2800 with 42.5 gr Varget and WLR primers in a 22 inch barreled T3. What is your overall cartridge length? Are you seeing any pressure signs?
     
  7. arroyobuck

    arroyobuck Member

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    I am not the OP, but my OAL is 2.243 (ogive to head measurement)...which is a ~.066 jump. That is as shallow as I can seat due to magazine box. Accuracy on the ABs average about an inch to 1.25 on 42 grains and tighten to less than an inch at 40 grns. The Interlocks are sub inch at 41.5 grns.

    I have seen occasional slight pressure signs at 42 gns of varget. (slightly flattened primer edges).

    I plan on trying some H414 when I have the time...
     
  8. jimbires

    jimbires Well-Known Member

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    gr1ffer , I did a fast look at quickload . the 140 accubond does not allow as much powder making it much slower than the Berger . I still think you should be able to get 2800 FPS . what is your barrel length ? and what is your COAL off the tip of your bullet . I'll run you a few numbers in quickload . from what I've checked in the past RL17 is usually higher velocity than varget or w760 in the 7-08 . Jim
     
  9. gr1ffer

    gr1ffer Member

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    Cheers for all the help I went back to the drawing board and tried a whole new bunch of components managed to get 2750 fps with 47 grains of h4350 which is a grain under max and exceptional accuracy did try a chrono test with elegy 22 subs and it seemed ok.
    Again many thanks having shot the rifle and this load to 300 yards I'd be happy to shoot a deer out to this range

    Kris
     
  10. Joe King

    Joe King Well-Known Member

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    I'm loading up my daughters 7mm-08 with 49gr RL19 and CCI200's manual lists it over 2900fps, I haven't chronographed it but she sure had no problem taking her 2nd (very large muley) buck at 300
     
  11. boogsy

    boogsy Member

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    I also have trouble reaching 2800fps with 140 gr. Have currently 4 7mm08 all like different things sierra spt work well in all, accubonds shoot well out of my wifes rifle. nosler ballistic tips are hard to beat and cheaper than the accubonds to. IMR4064 good, reloader15good, I never had luck with h414 but a lot of others have. Try some other pills maybe you can find one that will allow you to get closer to the lands. but if what your doing is working other than not getting velocity you would just keep doing it. good like with the best caliber ever!!
     
  12. backwoods83

    backwoods83 Well-Known Member

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    With the 140s a snugly compressed load of H4350 with Fed210Ms or BR2 primers is your best bet, and should easily get 2800+ in a 22" or longer barrel.
     
  13. gr1ffer

    gr1ffer Member

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    Sorry for late reply
    My barrel is 23" 1-10 twist
    My col is 2.8 that puts me 0.08 off lands
    Rp brass h20 of fired case is 55 grains
    Cci br-2 primer

    Again thanks for all your help if I can't get RL-17 to work the H4350 is very accurate and close velocity wise I don't think any living creature will notice 50 fps at 300 yards
    But you do need to draw a line in the sand somewhere.

    Kris
     
  14. jimbires

    jimbires Well-Known Member

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    I used your specs . 2.800 COAL , 55 gr H2O case capacity ( fired case ) , 23 inch bbl , 140 accubond , the 7-08 is rated to 60191 PMAX pressure .

    RL17 - 45.5 gr , 60102 pmax , 2913FPS , 100.6% case fill MAX LOAD
    45.6 gr , 60544 pmax , 2920FPS OVER MAX

    H4350 -46.7 gr , 59961 pmax , 2911fps ,108.9% case fill MAX LOAD
    46.8 gr , 60455 pmax , 2917FPS , OVER MAX

    H414 - 46.2 gr , 59956pmax , 2881fps , 100.6% case fill MAX LOAD
    46.3 gr , 60401 pmax , 2887 fps , OVER MAX

    varget - 42.3 gr , 60125pmax , 2826fps , 101.4% case fill MAX LOAD
    42.4 gr , 60560 pmax , 2832 fps , OVER MAX

    I think I covered all the powders that were mentioned . if you want to see a different powder let me know . general rule of thumb is to start 4.0 grains below max and work up while watching for pressure . hope this helps . Jim
     
    Last edited: May 20, 2012