Cant get my 7mm rum Sendero to group

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by elkkillinfull, Jul 23, 2012.

  1. elkkillinfull

    elkkillinfull Member

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    Hey I need some help. I just bought a remington sendero 7mm rum and cant get it to group at 200 yards. Its grouping .5" at 100 but cant get nothing at 200. Im using 180 bergers 90 gr. retumbo and oal is 3.65.
     
  2. Tikkamike

    Tikkamike Well-Known Member

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    What do you mean nothing at 200 yards? 1"? missing the paper? couple of east things to check first.
    1 did you get .5 at 100 one time or can you do it over and over?
    2 are you adjusting the parallax out of your scope?
    3 is the focus ring tightened?
    4 have you tried any other seating depths? Typically a match type bullet will shoot best when seated close to or on the lands, which means with a berger you may not be able to use your magazine without getting an extended magazine box.
    Make sure you eliminate every variable you possibly can.
     

  3. elkkillinfull

    elkkillinfull Member

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    Ya I have got it to shoot .5 a couple different times at a 100. But at 200 I am hitting paper but am getting 2.5" groups sometimes. I have adjusted the paralax and tightened the focus ring. And the load Im using I got from a buddy and he has good results with it out of his sendero 7mm rum. Heres a pic of what it looks like at 200.
     

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  4. Tikkamike

    Tikkamike Well-Known Member

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    Well assuming nothing has changed since your 100 yard groups, and everything is tight from your action screws to your scope rings then I would move the bullets .010 or so toward or away from the lands (closer will probably be better if that is possible) and see what it does with a couple more groups, Maybe you just need to find the sweet spot. Or Maybe try a slightly slower or faster powder. only change one thing at a time so you know when you finally start heading in the right direction. In the end you may end up switching bullets
     
  5. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    The faster 7mm bullet rounds don't always go to sleep at 100 yards. You can get an occasional great group with them at 100 with a poorly performing load. My dad had this happen with a 270 wsm, he hit a deer at 300 or so with it, and couldn't get another bullet into the deer until he got close to 100 yards away. A check at 200 revealed that his load was crap even though it shot sub moa at 100 the same day. He sent the rifle down the river, but a bit of 200 yard load development may have been in order.
     
  6. sledder1

    sledder1 Member

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    Were you using the same rest for both the 100 and 200 yard groups? Alot can happen if you change from a lead sled to bipod if the action screws are not torqued properly and/or if the action is not bedded properly
     
  7. elkkillinfull

    elkkillinfull Member

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    Ya I was using the same rest both times. I'm going to make sure the action screws are tight and take a look at the stock. And I am going to move .010 towards the lands and see what happens.
     
  8. AZShooter

    AZShooter Well-Known Member

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    Just checked Remington's website and they say the Sendaro SF II in 7 RUM has a 1 in 9 1/2 twist. For grins I looked at the XCR II and it has a 1 in 9 1/4 twist. Berger suggests a 1 in 9 for either the VLD or hybrid 180s.

    You didn't say which model Sendaro. IIRC the older Sendaros had the 1 in 9 1/4 twist. Perhaps your friend has the 9 1/4 twist and you have the 9 1/2?

    I think you should shoot something like a 160 accubond or maybe a 168 Sierra Matchking as a control. There is a possibility your rifle won't stabilize the 180s.

    FYI I had one of the early original Sendaros in 7 RUM and it didn't shoot well till I torqued the action screws to HS Precision's specs. Never tried any VLDs back then. Unfortunately I cannot remember what the torque numbers are now. You might want to ask HS.
     
  9. lloydsmale

    lloydsmale Well-Known Member

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    buddy had a win 70 in 270 wby mag that did the same. At a 100 it was a tack driver but at 200 it was 3 inch at best and at 300 he couldnt hit the broadside of a barn door. It did it with many differnt loads and bullets too. Never did figure out what the reason was.
     
  10. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    Also take a good hard look at the muzzle of the weapon and think about a flat base bullet. Most of the time when a load does this it's a boat-tail and a non-perfect muzzle combining to yaw the bullet a bit. With a cartridge as fast as the rum, it often doesn't show up at 100 yards. By 200 yards, the bullet has settled down and they are veering on their separate ways.
    I'd try seating depth changes first, and maybe a powder switch to h1000 or rl22 to get the muzzle pressure down to get the yaw down. If that won't work, switch to either a flat base or a bullet such as the nosler offerings with a more moderate tail.
    Possibly a lighter weight bullet is in order too. In my 7 rum I shot the 140 sierra(the 140 a-bond worked too) with 95 rl25 and a 215 in rem brass to 3.650". I also used the 175 hornady fb with I 5010 and rem brass with a 215.
     
  11. TXshooter

    TXshooter Well-Known Member

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    My 7mm ultra mag never did like the 180 gr bullets. I actually have it shooting a 140 gr bullet. I've had it shoot 160 really good to.
     
  12. baldhunter

    baldhunter Well-Known Member

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    I played with my 270 Win. the other day,shooting some 140gr Bergers.I used the method on seating from this link
    Berger Tips for Loading VLD Bullets, by Eric Stecker
    I was shooting at 200 yards.My groups were about 1 1/2 - 2".Once I hit my sweet spot seating depth load,I shot a one ragged hole three shot group.I can say I was quite impressed with those Bergers.I guess I need to play with the seating depth more on some of my other loads to see if I can get the same results.I've been working hard on perfecting a load that would shoot a one hole group at a 100 yards for years,only to find they may open way up at 200 yards.These days I'm changing my views and I'm working my loads at 200yards instead.The problem with that is other factors start playing with you more.The wind ,aiming error and scope parallax are most likely the ones that affect you the most.But I think it's well worth it to find a good load that will group tight not only a hundred yards,but also group tight at 200 yards.In a hunting situation,all things are not perfect like shooting off a well rested bench.Combine poor shooting groups and less than perfect shooting rest and your either going to miss completely,make a bad hit or just get lucky and score.
     
  13. elkkillinfull

    elkkillinfull Member

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    Ok well I loaded some 168 bergers and tried them thru it and they shot better then the 180s but still are not grouping. I shot 150 sciroccos and shot .75 MOA. I think I will move the 168s closer to the lands and see what happens.
     
  14. backwoods83

    backwoods83 Well-Known Member

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    In no way am I trying to be rude by saying this but, let someone else shoot your .5 moa load at 200 and see what there outcome is. With the horizontal and virtical stringing it may be you and the fact that you may not have enough time behind the trigger of this new addition. I hope you figure it out soon, 7 rum barrels have a short life span.