Load Development 7mm Rem Mag Berger 195 Extreme Outer Limits (EOL)

Discussion in 'Long Range Hunting & Shooting' started by jdmecomber, Oct 8, 2017.

  1. jdmecomber

    jdmecomber Official LRH Sponsor

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    The 195 EOL for the 7mm looked to be a really impressive bullet, but it appeared to be for the bigger cartridges in the 7mm family. I looked at Berger's Load Data for the 7 Rem Mag and thought, if I could get 2 extra inches of barrel, I could push the bullet fast enough for the Rem Mag. I decided to put a new barrel on the Savage Long Range Hunter in 7 Rem Mag. I ordered a Benchmark 8 twist for the 195 EOL. I knew by the bullet's length, I would not be able to reach the lands because my magazine capacity would be too short. The closest I can get is .028 if I want them to fit in the magazine.

    I really wanted to shoot the same powder as my .243 Winchester. I gave it a try, but the combination of bullet and powder just didn't work.

    I did a 10 shot ladder of H4831SC from 60.1 grains to 63 grains. It started at 2655 FPS and ended at 2911 FPS with no signs of pressure, but the group was 2.5 MOA. The instability was apparent by the group size. I was very happy with the FPS I was getting.

    I decided to go with a couple slower burning powders and just went a grain off of the max recommended powder charge. I shot 2 groups of 4 rounds each. Retumbo won the head to head with a .60 moa inch group.

    Now to find some pressure signs and get my max velocity...

    8 Shot Retumbo Powder Ladder:

    I started at 67.8 grains of Retumbo and went to 69.9 grains. It started at 2864 FPS and ended at 2984 fps. The last two shots had flattened primers with a little bit of heavy bolt lift at 69.9. So, it was about 1.5 grains more than book max, but I was getting 178 fps faster. I am looking forward to developing this gun. It does kick a little more than the 168 Bergers, but the trade off will be worth it. I am pretty happy with the .72 moa group of 8 shots and 2.1 grains of powder difference.

    Next up, I will shoot some groups from 69.3 to 68.1.
     

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  2. odoylerules

    odoylerules Well-Known Member

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    Wow that’s great speed! What length barrel?
     
  3. jdmecomber

    jdmecomber Official LRH Sponsor

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    I wanted two inches more than the factory barrel. Its around 26
     
  4. jdmecomber

    jdmecomber Official LRH Sponsor

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    The factory barrel is 26 with the brake, this one is around 27.75 with the brake.
     
  5. MAGA

    MAGA Member

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    Man.... a 195gr bullet out of a 7mm Rem Mag going 2900+ FPS would be tough to beat.
     
  6. jdmecomber

    jdmecomber Official LRH Sponsor

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    This development has been pretty tough. I wonder if a 7 Rem Mag isn't supposed to shoot a 195 at 2880+ :) I would assume that it's like shooting a 6mm 115 vld in a factory .243. It's probably not the best choice, but it might work with some adjustments.

    I just finished the powder and lands testing.
    I am using some Winchester brass that is brand new, and man was it beat up. I fire-formed some cases while doing the powder testing.

    I am shooting prone off some bean bags and using an atlas bipod. There was a little bit of wind today... Enough excuses?

    Powder Testing Retumbo

    These 4 shot groups all had 3 close and one flyer opening the group around an moa.

    Round 1
    68.1 (3 shot) .462 MOA
    68.4 (3 shot) .186 MOA
    68.7 (3 shot) .336 MOA

    Final Test
    I tried 68.4 and 68.6
    The bullet seems to be pretty erratic, however, the final powder charge was 68.4 grains and will do.
    68.4 (3 shot) .234 MOA (4 shot) .553 MOA

    Lands Testing
    68.4 grains of powder
    I used .010, .040, .060 and .080 jump into the lands. I didn't want to go .120 because the bullet was wayyyyy into the case.

    First Lands Test
    The winner surprisingly was .080 jump with 4 shots at .45 MOA. The great part is they fit in my factory magazine with ease.

    Final Lands Test
    I used .070, .080, and .088. It's pretty shocking that a small movement in depth would open up a group.

    .070 (3 shot) .251 MOA (4 shot) .579 MOA
    .080 (4 shot) .371 MOA

    At this point, I had mixed feeling about trying to do this with a factory gun and a bullet that's truly designed for the larger 7mm family (in my opinion).

    Final Group Size and Adjusted Zero
    68.4 grains at .080 jump (3 shots) .30 moa (5 shots) .68 moa

    To finish off the development for today, I adjusted the scope to zero the rifle. That black square is .50 inches

    Adjusted to Zero
    4 shot .46 MOA

    My final thoughts are that this bullet is probably not being optimized for this factory gun. The 180 VLD or 175 EOL would probably be a better choice and would not be so hard to tune with this weapon. However, I am pretty happy with my adjusted zero group and location, and I am ready to shoot some deer (and maybe a bear) this fall.

    Tomorrow I will get the hot and cold temperatures for the powder and the final velocity. I think it's going to be around 2875 FPS.
     

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    Last edited: Oct 9, 2017
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  7. odoylerules

    odoylerules Well-Known Member

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    Factory 7mm, pushing 195’s at nearly 2900 fps sub half MOA...sounds phenomenal! What were you hoping for?
     
  8. jdmecomber

    jdmecomber Official LRH Sponsor

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    .0001 moa ;)
    We shall see tomorrow how the extreme spreads and SD are. I will probably finish off with the scope tracking too.
     
  9. BUSTINDOGS

    BUSTINDOGS Well-Known Member

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    I use this bullet in a straight 7-375 Ruger and started testing with H1000 and Retumbo and found same results as you have, I could only get about 2900 fps out of 74.5gr Retumbo and would shoot good one day and poor the next. I switched to reloder 33 and can get over 3000 fps safely and as long as I keep up with barrel maintenance it shoots. I have found reloder 33 to be dirty turns my muzzle brake black, like inside of a chimney black in about 40 rounds. I would be very interested in seeing what reloder 33 would do in your rem mag. I bet if you could get enough in there you would see excellent velocity and accuracy.
     
  10. jdmecomber

    jdmecomber Official LRH Sponsor

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    I was just thinking about what I would really be chasing if lets say I could get another .20 moa out of this load.

    These 6 groups are all 68.4 grains at .080 or .070
    .371 4 shots
    .455 4 shots
    .460 4 shots
    .579 4 shots
    .553 4 shots
    .680 5 shots

    19 rounds are .371 moa are under
    2 rounds around .460 moa
    2 rounds around .579 moa
    2 rounds around .680 moa

    I think this shows that 76% of the time my rounds will be .371 moa or under.
    84% .460 moa or under
    92% .579 moa or under
    100 % .680 moa or under


    I will be happy with these numbers as long as the gun stays consistent and has a decent extreme spread. I will have this on steel maybe Tuesday and can stretch it out to 1300 yards and see how it does. It's just a hunting rifle and steel makes great practice.

    I sure did like the final adjusted zero
     

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  11. jdmecomber

    jdmecomber Official LRH Sponsor

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    Average out of 5 was 2923 FPS, Low of 2908, High of 2942
    Standard deviation was 13.5
    Extreme Spread of 34 FPS

    I can get this down.
    I haven't cleaned the brass yet in 2/3 firings and haven't weighed any of the brass which usually has some large variances in weight.

    Also we broke down and purchased the Sartorius ENTRIS64-1S Analytical Balance Scale, that should help.


     
  12. brentc

    brentc Well-Known Member

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    Agreed. 2900 with the 195 is a viable long range load. A long barreled 7RM with a stiff charge of Retumbo will crank 180s along at around 3050 fps, so low 2900s should be about right for the 195s.
     
  13. curtiscd

    curtiscd Active Member

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    Using RL-33 through a 26” barrel I was able to hit an avg of 2875.
    195 EOL HBN coated
    Hornady brass
    Fed 215
    76gr RL-33

    Retumbo averaged a touch faster with an avg of 2897 with 69gr

    Grouping was poor with Ret., but .5 MOA with RL-33. My seat depth test proved .120” from lands to be best, but seating that deep really would have been near impossible. I chose to jump back to the 175 EH and save the rest of my 195’s for my STE
     
  14. jdmecomber

    jdmecomber Official LRH Sponsor

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