7rum build

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by cahunter805, Jan 2, 2013.

  1. cahunter805

    cahunter805 Well-Known Member

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    Hey guys,
    Have a buddy that is looking to build a 7rum. I am helping him and was wondering what twist and if everyone is setting them up with factory freebore or shorter? Also wyatts box? Will mainly be shooting 180vld and hopefully the 195eol. Any recommendations appreciated.
     
  2. AZShooter

    AZShooter Well-Known Member

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    I am certain there are others that can offer more but I'll take a stab at it. You didn't mention action choice. Some actions will not allow a RUM case to pass the feed rails. Standard Rems won't. A friend wanted to build a LR 338 RUM and had to buy a 300 RUM for the action to save on machine work.

    As for twist Berger says a min of 1 in 8.5 for the upcoming 195 EOL bullet. I can add that I was mislead on purchasing a 1 in 7 twist for a 7 Rem Mag to shoot 180 VLDs a few years ago. It was only offered in a 3 groove and proved to be a BAD combination. The combo of fast twist and 3 groove caused even the thicker target VLDs to come apart in flight once the barrel showed some wear. Can you believe it was just past 200 rounds? So IMO get a barrel with more than three grooves.

    The wyatts box can be useful. I have added a few to my rifles. They make a special one for the RUMs with some cutouts on the sides which allow the larger dia cases to fit.

    I have read that there needs to be some freebore with the 7 RUM. Perhaps others can comment on this.
     

  3. cahunter805

    cahunter805 Well-Known Member

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    Thanks for the info. This will be a rebarrel so we have a rum action already.
     
  4. Nimrodmar10

    Nimrodmar10 Well-Known Member

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    From my experience with a factory Remington 700 Sendero in 7 RUM, save yourself some money, time and frustration and pick another caliber. The factory barrel had .400" of freebore and would not shoot with anything. The Berger 180 VLD would have had to have been 1/4" outside the case neck to touch the lands.

    I finally sent it back to Remington and they said they would not rebarrel it in 7 RUM caliber, that I should pick another caliber. They said every barrel they had in that caliber was defective. They quit chambering in that caliber in the Sendero.

    Pick another caliber.
     
  5. AZShooter

    AZShooter Well-Known Member

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    I owned three 7 RUMs and all would shoot with a jump to the rifling. One was a sendaro. One was put together with a PT&G reamer. Third one was a LSS which even stabilized the 180 VLD with a jump! The other rifles shot 140 nos bt, 160 accubond and a 168 sierra.
     
  6. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    My 7 rum liked the 140 sierra and 175 hornady and it jumped just fine. My freebore stopped at 4.1" and I loaded them to fit the mag, so about 3.650". The thing won't have great barrel life, so you will need to baby it and not heat it up. Shoot something else for range practice. Rem did produce some bad 7rum barrels; I got stuck with one that wouldn't shoot better than 2 moa no matter what I did. Fortunately the gun shop took it back and I later found another.
     
  7. bgouin

    bgouin Active Member

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    My factory Sendero in 7 RUM likes 140 gr. Noslers and Corlokt ultras, and 162 gr. SST's, but does not like 168 gr. Bergers. I have not tried the 180 gr Bergers yet, but I am concerned about barrel errosion, so I have been playing with 190 gr. Matrix VLD's. They shoot well and I am getting 3050 fps from them. I am trying to use heavy bullets, and hence, less powder to prolong the barrel life. The 180 Bergers may also work in my rifle, but I don't have the time to try every combination, and the 190's from Matrix perform well on the range. I have not tried them on game, maybe this year.
     
  8. GB3

    GB3 Member

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    I run a 7mm Ultra with a 30" 1-9" twist Krieger with factory throat measurements. It shoots 162gr A-Max really well. I suggest getting the Wyatt's extended box, it will open up your loading options. I couldn't get 168gr Bergers to work without loading them longer than the box would hold, Even with the extended box. Once i got it figured out, I really like the rifle. But be prepared to invest a fair amount of time and scratch your head alot getting it figured out. In the end, its worth it when you're shooting a 162 gr bullet 3500-3525 fps and holding 1/2" groups at 100 yds. Best of luck!
     
  9. TOM H

    TOM H Well-Known Member

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    Here is magazine spec

    CFE-9 Magazine Box, WYATT'S OUTDOOR, INC.

    I shoot few of the Berger and most that I use 1/2 the length is from the ogive forward. You might want to buy some bullets and make up some dummy rd and get magazine and see how they fit

    The 7Rum case length is 2.850" long and Berger 180gr VLD bullet is 1.525" long not sure how long the 195 gr be.

    Myself I do that first make sure what bullet you really want to use then go from there.

    Well good luck
     
  10. Edd

    Edd Well-Known Member

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    Is anyone using a custom chamber and seating the 180 gr VLD against the lands?
     
  11. jwing

    jwing Well-Known Member

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    700 rem, brux STD Palma fluted, 28 in, muzzle break. 1-9 t, 180 hybrid moly , retumbo, fed gm215m, 3200 shoots 1 inch at 600 shot 10 in at 1 mile... good luck
     
  12. TOM H

    TOM H Well-Known Member

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    Did you give up on the 7RUM

    7 rum load data with 180 hybrid
    Please help with 180 vld load data for 7 rem ultra mag.

    H 1000, retumbo, magnum, 7828, vv-n570?