7mm RUM loading advise.

Discussion in 'Reloading' started by Andy W, Sep 17, 2006.

  1. Andy W

    Andy W Well-Known Member

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    Apr 17, 2006
    I have a few questions for you guys as I have never shot or loaded for these big magnum cartridges. I have a lot of reloading experience but all with 22 and 24 caliber offerings (22-250, 6BR, and 6mm Rem.) The gun I purchased is a Remington LSS in 7MM Ultra Mag. I plan on starting with the 175 SMK over Reliant 25. Here are a few questions I am looking for help on;
    • The way the factory has throated the chamber I cannot even come close to touching the lands, and seating the bullet out as far as I can in the magazine gets me an OAL of 3.655 with the 175SMK. I guess with the throat this long you guys never play with seating depths? Just play with the powder charge for each bullet/powder combination?
    • I plan on starting with the 175 SMK. My factory twist is 9.5 and they recommend at least an 8.5 twist with this bullet. I figure with the velocity that the Ultra Mag pushes this bullet the slower twist should still work? Anyone else getting this bullet to work with the 9.5 twist?
    • If looking to re-barrel in the future do you guys stick w/ SAAMI spec, or do you go with a tighter neck/chamber and neck turn?
    • How many of you guys shoot your 7mm UM without a brake? My gunsmith says he can make me a brake that will have the same POI without the brake when I am hunting with it. Still on the fence with putting a brake on it.

    I initially purchased this gun for the action/bottom metal only as I am a leftie and where I live it is difficult to get any gun in a left hand offering. The 7MM UM is all that they had in left hand. My initial idea was to build a 300 UM, or a 300/338 UM. I figure I have the gun now and it will take me at least 3-5 months to get the stock and barrel that I want. I may as well see if this gun shoots! If it does not do what I think it should I can simply sell the dies and go back to my initial plan.

    Thanks for your time and thanks to you guys who support and give guys like myself some of your time and expertise.

    Andy.
     

  2. sambo3006

    sambo3006 Well-Known Member

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    I've got a left handed LSS 7RUM myself! I haven't had the chance to work with it a whole lot. I've been shooting 150 gr Ballistic Tips at 3400 fps. The recoil from the bench unbraked is fairly sharp. A brake should tame this round nicely. I just got a Limbsaver recoil pad for mine, and that is probably all it needs.
    The other guys should be able to give you more info on the other stuff.
    Good luck and good shooting!
    Sam
     

  3. redstater

    redstater Active Member

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    Apr 26, 2005
    I talked to Sierra today as I also need 7 rum advice. I was told that they do not have data for this cartridge as they could not get good accuracy in their testing. With some proding he did say that with a 168 smk he would start with a Fed 215 and 84-88 grains of Rl 25. He also stated that the 175 smk will not work with a slow twist.
     
  4. dancoman

    dancoman Well-Known Member

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    Jul 11, 2006
    My 7mmRUM likes 94gr RL25 and 150 scirocco's
     
  5. Andy W

    Andy W Well-Known Member

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    Apr 17, 2006
    I also talked to Sierra and they told me they are not publishing any info because the cartridge is so overbore. I have loaded the 175 SMK with both Retumbo and the RL 25. They are out of stock of the 168 SMK in my area. I figure at 3000+ fps the 175 should stabilize. I will report back with results.
     
  6. Casey Napier

    Casey Napier Well-Known Member

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    Jul 22, 2006
    My 7MM UM prefers IMR 7828, but I have only tried 140 and 150 grain bullets. This seemed to be the magic powder in the factory tube, and also the Pacnor that I screwed on later.

    RidgeRooster
     
  7. davewilson

    davewilson Well-Known Member

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    Ridgerooster, what part of Kentucky are you from? was interested in hunting down there.

    i've only shot the 180-200 bullets. used 872 powder but 869 or retumbo work well also. i had a 30" barrel.
     
  8. Guest

    Guest Guest

    I have a 7mm WSM with a 27" 1-9" twist Broughton 5C barrel and shoot the 175 SMK's at 2970fps.
    They shoot .75moa 5 shot groups at 1K when I do my part.
    I think I would give them a try in your RUM as the extra velocity should make them work.
    Wayne aka WAMBO
     
  9. Casey Napier

    Casey Napier Well-Known Member

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    Jul 22, 2006
    Dave,
    I am from Hazard KY, but I know live in Carrollton, which is half way between Louisiville KY and Cinn. Ohio, straight down the Ohio river. Hazard is in the Mountains, and deer hunting is pretty tough because of the rugged terrain, but Carrollton is very good. Western Kentucky is even better, so if I was coming from out of state, I would hunt in the western 1/3 of the state. This is the area where all the press about the big bucks is coming from. There are several good public areas in western KY, and several good outfitters.
    Good Luck
    RidgeRooster