7 RUM hard on barrels?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by buckbrush, Jan 2, 2009.

  1. buckbrush

    buckbrush Well-Known Member

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    I am going to rebarrel a gun that is currently a 7 Rem Mag. I was thinking of going with a 7 RUM but have heard that it is a barrel burner. I'd like to shoot the 180 Bergers over 3100 FPS so the RUM seems like the best choice. I just don't want the barrel to be shot out after 500 rounds.

    How fast can the 7 Rem Mag shoot the 180 Bergers? I am thinking 2950 would be about max.
     
  2. Broz

    Broz Well-Known Member

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    Buckbrush, We are on the same page this am. I just got off the phone with a friend that wants to try the 180's in his 7 rum. The question we have is , will the brass hold up, and at what speeds.

    Interested in what some that have tried this have to say.

    Jeff
     

  3. MagMan

    MagMan Well-Known Member

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    I found my log book. With a 30" tube and 100.3 grains of US869 I would get 3375 with the 180 Bergers. I'm not sure how hot that load was but I never marked it as having pressure signs.

    3300 is where the accuracy was.

    4 to 5 loads per case was pretty common.
     
  4. AZShooter

    AZShooter Well-Known Member

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    The one factor that has not been mentioned is barrel length. So often we read articles on wildcats as in PO Ackley's book and there is no mention of the length. Same goes for twist.

    I am in the process of putting together a 30" 7 Rem mag and would like to hear what velocities can be expected with a 180. 1 in 7 twist, which should slow things down a bit.

    For what it is worth. My friend is making a 30" 1 in 7 twist, 7 STW to shoot the 180 Berger VLD.
    In his conversation with Dave Kiff barrel life was discussed. Dave, apparently is a lover of this chambering. He said it took several burned out barrels to realize he could extend the life by keeping the bullet into the rifling instead of any kind of jump. My friend's rifle mag has enough room after a wyatts mag box to be able to chase the rifling. My action is a mauser style and too cost prohibitive or perhaps impossible to lengthen the mag box for the STW or I would have made one too. The 7 Rem Mag fits well and I can chase the rifling for the life of the barrel.

    Can anyone out there give us a clue on velocity with the 180 VLD and the 7 Rem Mag?

    ---------------------------------

    Perhaps we have missed the boat. The 284 is capable of 3000 fps with a 180 using RL-17!!!
    Alliant Reloder 17

    from link:

    Rifle #1: .284 Winchester with Berger 180s
    .284 Winchester Prone Rifle built up by Warner Tool Co. with Masterclass Stock, Barnard Action, Broughton 1:9" twist 5C barrel (31.5" long).



    All loads used neck-turned, Winchester-headstamp .284 brass, CCI BR-2 primers, and naked (non-moly) Berger 180gr VLD bullets seated .010" in the lands:

    51 gr RL 17 - Mean Velocity 2881 fps, ES 17, SD 7 - No pressure issues at all
    52 gr RL 17 - Mean Velocity 2953 fps, ES 19, SD 7 - No pressure issues at all
    53 gr RL 17 - Mean Velocity 3003 fps, ES 25, SD 10 (Slight sticky bolt lift on 3 rounds - this is about top end for my liking but I would not hesitate to shoot it however if it turns out to deliver good accuracy).

    Big Speed Gain with Reloder 17 in .284 Win
    RL 17 clearly enables me to run the Berger 180s easily 125-150 fps faster that I normally was able to shoot them with H4350 and H4831SC in this rifle. My previous load ran around 2825 - 2850 fps with the Berger 180s and that was about all I could get out of it.

    ------------------------------------

    I wonder if RL-17 would work in the 7 Rem mag and 7 WSM?

    -------------

    Sorry not meaning to hijack your thread, I feel these topics are related.
     
  5. JeffVN

    JeffVN Well-Known Member

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    I am shooting a 7WSM - which has slightly less case capacity than the 7RemMag (81 grains vs 83), and I have no trouble (in Las Vegas in the summer) getting the berger 180s to 2,940 fps with a 28" 1:9 twist Kreiger barrel. I see no reason to step up to the RUM if your goal is 3,000 fps or slower with the Berger 180s. If the goal is 3,100+ then you'll need the additional boiler room in the RUM.

    I also see no reason to use anything faster in twist than a 1:9. my 1:9 twist works fine for the Berger 180s and 175 smks at 2,800 fps. That was my velocity with a summer load out of my 7WSM in Houston with a 26" barrel and an OAL of 2.90".

    check out this page:

    7mm Cartridge Guide

    Jeffvn
     
  6. AZShooter

    AZShooter Well-Known Member

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    Thanks Jeff,

    I figure I'll get 3050 with a 30" barrel and the 7 Rem Mag with 180 VLDs. Unfortunately Lilja only offers a 1 in 7 for the barrel my friend and I ordered. He said it would work fine. I figure it might take some speed from the package.

    If I were to begin from scratch I would seriously consider making a heavy 284 to shoot the 180 VLDs. Now that RL-17 has redefined things it would be a great package with some good barrel life.

    Personally I had a 7 RUM Sendaro and it was a screamer with moly'ed 140s, very accurate too. Unfortunately it didn't respond to VLDs so it was moved along. My 300 RUM doesn't like VLDs either but it does thrive on the .588 BC 200 Accubond. My friend had Dave Kiff make a 7 RUM reamer that is supposed to be designed for the VLDs. I suppose one of these days I'll make a 7 RUM when the 300 RUM gets tired. I really like the 7 RUM brass and the concept of a beltless mag case that utilizes all the space that a 2.8" case can offer and still work in factory actions.

    7mms have come a long way and there are a ton of options these days. Fun to dream of the next one.......
     
  7. buckbrush

    buckbrush Well-Known Member

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    I am leaning toward the RUM since it is a lazer. 3300 fps with a 180 VLD is amazing. I was really concerned about the barrel life issue.

    I would probably stay with the Rem Mag but my brass has all been fired 5-6 times anyways and a lot of the primer pockets are loose so it is probably no good anymore.