10 MOA for 7mm Rem Mag

Discussion in 'Long Range Hunting & Shooting' started by Billinsd, Oct 29, 2008.

  1. Billinsd

    Billinsd Well-Known Member

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    I'm thinking would 10 MOA for a 7mm Rem Mag enable me to adjust a 3mm scope to shoot at 1000 yards? And also sight in at 100 yards?

    Has anyone figured this out?
    Thanks
    Bill
     
  2. linksmechanic

    linksmechanic Well-Known Member

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    I use a 0 moa and I'm good to 1200 yards with 180 bergers.
     

  3. JeffVN

    JeffVN Well-Known Member

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    I believe that a 0 MOA base will enable you to shoot to 1,000 yards with a 7mmRem. Mag and an appropriate long range load. MY 7WSM gets there in 24MOA with Berger 180s. Then again, it depends upon the make of your scope, the load that you are shooting, and the bullet that you are using.

    JeffVN
     
  4. Billinsd

    Billinsd Well-Known Member

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    Thanks for the info. I may never shoot to 1000 yards, but it would nice to have the option. Where I live it is tough to find a place shoot out to 600 yards.

    Thanks
    Bill
     
  5. Sendero_Man

    Sendero_Man <strong>SPONSOR</strong>

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    I don't think your gonna get there with a 3mm scope.... LOL
     
  6. Billinsd

    Billinsd Well-Known Member

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    Ha, I see what you mean!!!! I could probably get to 100 yards with a 3mm scope!!! Sorry, I'm tired, got a newborn and been working lots of OT.

    I meant 30mm. I got mm and cm cornfused..

    So, say a 180 grain berger drops 300 inches at 1000 yards, that is 30 MOA, right? And if my scope has say, 65 MOA, figure you divide in half and have say 32 MOA with a zero MOA base, right? So by adding a 10 MOA scope base that would give me another 100 inches of play at 1000 yards, right?
    Bill
     
    Last edited: Oct 31, 2008
  7. bigg_sexy1

    bigg_sexy1 Well-Known Member

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    Looks about right to me Bill, just wondering have you looked into a 20 MOA base to give yourself lots of room?
     
  8. MagMan

    MagMan Well-Known Member

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    There won't be any wondering with a 10 as it is probably the safest bet.
     
  9. 4xforfun

    4xforfun Well-Known Member

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    First off.....big difference between bullet drop and bullet path!

    Example: berger 180 vld @ 3000fps (1300 ft @ 30degrees) 100 yard zero

    Bullet Drop.......274 inches at 1K.

    Bullet path......237 inches at 1K.

    You will need to adjust 23 3/4 min to go from 100 to 1000, NOT 27 1/2 min

    Big , Big difference.

    As for your question...you will have no problem with standard ring/base setup if you use a Leupod or Nightforce. This I know. If you are using another brand, check the adjustment range of those scopes before you buy.

    Also, don't automaticaly assume that your scope will be at the middle of its adjustment range when it is zeroed at 100 yards. I have seen many times the need for the scope to be cranked to near the end of its adjustment range just to get on at 100. That may not leave you enough adjustment to get to 1K.
    I would say go wit the 10 MOA setup, but be sure to lap in the rings, or have someone do it for you.

    Good Luck.
     
    Last edited: Nov 5, 2008
  10. Billinsd

    Billinsd Well-Known Member

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    Thanks for the post. Would you mind explaining bullet path?
    Thanks, I did not know that.
    So, do you mean lap the rings so I can get the gun to shoot to 1K, or to relieve the pressure points so the gun will shoot more consistently?

    Also, would you mind posting the same data for 168 grain 7mm mag Bergers?

    Thanks
    Bill
     
  11. 4xforfun

    4xforfun Well-Known Member

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    Drop: this is the amount the bullet drops at a given distance. the bullet leaves the gun level with the horizon, and will start to drop right away. We are not concerned with a zero, just the actual amount the bullet drops.

    Bullet path: This is the path the bullet takes when zeroed at XXX yards.


    Lets assume your 168 (3000 fps) is zeroed at 300 yards, and your scope height is 1.9 inches above the bore. The bullet leaves the bbl at an upward angle, crosses your line of sight on an upward path at about 25 yards. and is on its way back down when it crosses your line of sight again at 300 yards. at around 190 yards the bullet is actualy 4 inches high. Now, although your bullet is dead on at 300, the actual drop of the bullet is actualy 19 1/4 inches.

    Now with the same setup, but at 1000 yards, without dialing up....just leaving the gun zeroed at 300 yards. Again, you bullet crosses your sight line on the way up at around 25 yards. It again crosses it on the way back down at EXACTLY 300 yards (300 yard zero) and the bullet will hit 214.54 inches low at 1000 yards. BUT.......you bullet actualy dropped 283 inches, its just that you had the gun pointed at an upward angle to your line of sight.

    bullet path....-214.54 inches = 21 1/2 min of adjustment to hit dead on at 1 K.

    Rings don't always line up exactly with each other, which binds on the scope tube when you tighten up the rings. Lapping rings is very important when you are using tapered rings-basses. Basicly, the lapping kit includes a steel rod, either 1 " or 30 MM, and some lapping compound. You install your basses and rings on the gun, take the top half of the rings off, put a little compound on the bottom rings, and slide the rod back and fourth untill the rod makes good contact with the rings. You are basicly sanding down the inside of the rings smooth and strait to prevent binding on the scope.

    Also, I have seen factory guns where the holes for the scope bases are not exactly on center, or the bbl has a slight bend(we are talking thousands of an inch here, not a big amount). You can find the center of the adjustment on the scope, mount it on the gun, and be 4 feet off at 100 yards!!

    Hope this helps. I did it in a hurry and deer gun season starts at noon, so i probably made some typos, spelling errors, among other things.

    You guys feel free to correct me and I will check things over later.

    Good luck
     
  12. Billinsd

    Billinsd Well-Known Member

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    Thanks. I've always refered to bullet path as the drop. I see what you are talking about, thanks.

    Yes, I knew about lapping the scope rings. I've never done it though.

    I still do not undertand why lapping is more important with tappered rings or bases?

    So if the scope base holes are not centered or the barrel is slightly bent would lapping the rings help? If so how would it?

    How would I measure to see if the scope base holes are centered and how can I make sure the scope is perfectly square on the rifle?

    Thanks for your help, I understand about getting out and hunting. Take your time answering when you have time.

    I really appreciate the help!!!!!!

    Thanks
    Bill
     
  13. 4xforfun

    4xforfun Well-Known Member

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    The only thing lapping the rings does is protect your scope. Nothing more.

    If the holes for the scope bases are crazy off you can either have a smith fill em and re drill em, or get some adjustible bases, like the ones made by Leupold. They have opposing screws on the back of the bases (one piece base) to help adjust l-r. Just center up your scope's adjustment and get the basic zero with the screws. Something tells me that they are called S-T-D bases, but I am not sure. I have a few guns with them, and they are very reliable.

    As far as a bent bbl, replacement is the only cure. I have never herd of a tube so far off that it was impossable to fix with adjustible basses for L & R and shims- tapered bases for the U-D. Of course, I don't get out much!!:D:D

    Good luck!!
     
  14. Billinsd

    Billinsd Well-Known Member

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    Thanks a lot, I appreciate it.

    So, is there anyway to physically, and practically measure whether the scope mount screws are off center and if the barrel is bent?

    Thanks
    Bill