7mm RUM Loads---actual performance

Discussion in 'Reloading' started by POP, Aug 5, 2007.

  1. POP

    POP Well-Known Member

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    What velocity are you guys getting with 140-160 gr bullets? Any loads would be great.
    I have heard/read some loaders getting 3400 fps with 150's and 3600 with 140's.

    Can this be safely done?
     
  2. philny1

    philny1 Well-Known Member

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    7mm Rum

    I've been messin' with a Sendaro 7 RUM the last few weeks, can't find much data for em. Tried working up a load for the 160 gr Accubond using WC872 took 97gr to break 3000 fps, just quit there. Went to RL-25, 91 gr will push the 160 AB to an avg of 3349 fps in my gun.
    Thinking of trying some Berger 168 gr, maybe not the 160 AB is sure shooting sweet.
    Bought this Sendaro here on LRH, has Nates muzzle brake, a Jewell trigger and a sexy spiral fluted bolt. Fun gun to shoot, recoil is minimal can see my hits at 300 yds which is as far as I've taken it to date.
     

  3. POP

    POP Well-Known Member

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    I had a 7mm STW years ago. It was a Sendero.
    140 NBT's with 80 gr of 7828 gave me 3502 fps on the nose! Accuracy was 1.25" at 300 yards---on average.

    So with xx more grains of powder capacity of the rum....who knows?
    Just never seen it "written" on a trusted source......
     
  4. davewilson

    davewilson Well-Known Member

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    never shot anything smaller than the 180's out of mine. had a 30" barrel and went 3250 with 872 powder.
     
  5. philny1

    philny1 Well-Known Member

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    STW

    I too had a STW. Accuracy load was 160gr TSX over 79 gr IMR 7828 for 3351 fps. 80 gr would push it over 3400 but groups opened up.
    With 150gr TSX, 81gr of 7828 would push it a tad over 3500 fps with decent accuracy. This is out of a Wby Accumark that had been to Hill Country Rifle.
    My 7 RUM with 91 grs of RL-25 is not max out, probably could push 3400. Shooting real sweet, why bother another 50 fps isn't gonna do much for me and that elk won't know the difference.
     
  6. philny1

    philny1 Well-Known Member

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    RUM

    Do you think the 160gr AB is to light for 872 in the 7 RUM
     
  7. strictlyRUM

    strictlyRUM Well-Known Member

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    I have used 869, retumbo, h1000, and I would have to say that the 872 is too slow for that bullet expecially that barrel length. H1000 is my go to powder for the RUMs. In the 7RUM I just posted pictures on, with the 176 and 180 grn bullets 869 seemed too slow. I was getting blazing speeds but ESs that bettered 75! That is untill I dropped her down. I think I was pushing powder and not getting a good burn. I used every primer under the sun. Same for retumbo. I got the 140s to go 3600 with 94grns of H1000 and sane ESs. I have a 28 in barrel that seems to be very fast. I cannot run max loads most of the time. I got the 176 molly Cauterucios going 3500 before I SAW pressure. Still easy to open bolt just a shiny ejector mark and hard to size brass. For some reason my 9 twist wont shoot the heavies though, so I am stuck shooting 140 AB at 3450 getting clovers at 200 and in the 1s and 2s at 100. I sure would like to figure out why all the heavies string horizontally though. If anyone could help me out on that I would appreciate it. I tried everything. Just threw some bullet lights through as a last ditch and bammo! No stringing good ES and nice tiny groups.

    Jason
     
  8. davewilson

    davewilson Well-Known Member

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    did you ever check the rate of twist to see what it actually was?
     
  9. strictlyRUM

    strictlyRUM Well-Known Member

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    Its nine.
     
  10. philny1

    philny1 Well-Known Member

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    Did some shooting this AM, calm overcast morning. Had to decide weather I wanted a single shot or repeater, this rifle has been shooting great with the bullet just of the lands. Kinda dreaded changing things plus I had to open a new lot of RL-25. Seated the bullet deeper to use the mag, gave myself .005 clearance. Should have probably another .005, but I might just go with one in the mag and one chambered. Started back at 100 and with three shots got it about 2" high, went out to 300 yds and after a sight adj shot a three shot group measuring 1.340". That's about as good as it gets for this ol' boy.
    160 gr AccuBond in front of 91gr of RL-25, guess I'll stick with this load til something better comes along.
    Also have a 338 RUM I doing alright with, 99gr RL-25 and 225gr ABs giving me 3150-3200 fps depending on the lot of brass Im using. Getting 1½-2½" groups at 300 yds I've taken this one out to 750 yds with good results. Another load using 92gr of RL-22, I'm getting 3125 fps with about the same accuracy.
    Will be out to CO in Oct with a cow and bull tags. Didn't draw on deer this year. One of these RUms, maybe both will be going with me.
     
  11. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    You will hear some pretty impressive velocites being thrown around with the 7mm RUM. It is really dependant on barrel length and chamber design.

    In average, if your shooting a factory 7mm RUM, you should see around 3450 fps for a top end load with a 140 gr bullet. THe 160 gr pills will on average allow you to get to around 3300 fps.

    This is from developing loads for many factory rifles back when I had time to actually do that for customers. Anything much over this in a factory 26" barrel will result in dramatically shortened case life due to primer pocket loosening.

    I have also heard many claims of extreme performance with the 7mm STW. Again, most do not list what barrel length is used and also how long their cases lasted. To my way of thinking if you can not feel the primer being seated but it does not fall out of the case, this is not safe pressures to be loading to!!!!

    Also, with Wby rifles, I would be suspect of the freebore situation allowing them to be loaded to much higher chamber pressures then standard chamber rifles.

    I have seen some Wby rifles with very long freebore in 7mm STW and some with standard length. BAsically these are two different rounds when handloading.

    All in all, the STW should be topped out around 100 fps less then what the RUM will offer for same length barrels from what I have seen in testing both rounds.

    Again, max velocity potential depends on what you accept as pressure signs. Personally, if I see an extractor marks of any significance or if the primer pocket loosens before 5 firings, the load is to hot. Thats just me. Many have no worries about only getting two firings per case which will result in much higher velocity potentials!!! Thats one way to get a 7mm STW to match a 7mm RUM but its about the only way.

    Kirby Allen(50)
     
  12. J E Custom

    J E Custom Well-Known Member

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    7 Rum

    Dito on what kirby said.

    I had a custom 7 STW bilt when thier was no brass except
    8mm rem mag looking for a really flat shooter.

    The rifle was bilt on a browning hi wall and had a 31'' barrel.

    After extensive testing this was the results.

    The highest velocity reached was 3817 with a 120gr bullet
    but accuracy fell off at around 3700ft/sec.

    With the 140 3538ft/sec was the best I could do but brass life
    was 2 to 3 rounds at best.

    Later I bough a Rem sendero in 7 STW an was only able to get
    3468 ft/sec with a 140gr bullet.

    I now have a 7 RUM with a 26'' barrel and factory loads produce
    3543 ft/sec with a 140gr bullet.

    These are real velocities using a ohler 35p chronograph at 75 o
    NOTE: All these loads were to hot in the summer (Texas avg 95
    to 100 o )

    So be happy with a usable 3500 ft/sec load with a fac 26'' barrel.
    you might be able get a little more with reloads and still be safe.

    I have no data on longer barrel 7RUMs.

    I hope this helps
    J E CUSTOM
     
  13. POP

    POP Well-Known Member

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    What is your load with the 140's at 3540?

    please
     
  14. J E Custom

    J E Custom Well-Known Member

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    7 Rum

    Pop

    It is the remingtion factory with the 140gr noz partition
    (hard to find sometimes)

    And forgive the spelling on the other post (must have had
    a brain fart).

    I havent had time to work up a hand load yet and grouping
    was .519 5 shot,s @ 100yrd,s (not bad for factory loads
    in a factory REM 700). standard deviation was 24 ft/sec.
    not great but ok.

    PS Stock is a AI walnut hunter.

    J E CUSTOM
     
    Last edited: Aug 6, 2007