Quantcast
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Calculating Minimum Scope Ring Clearance

Discussion in 'Rifle Country' started by numaone, Jul 18, 2009.

Thread Status:
Not open for further replies.
  1. numaone

    numaone Member

    Joined:
    May 25, 2009
    Messages:
    114
    Location:
    North Carolina
    Is there a webpage calculator that can tell me the minimum height that my scope rings need to be for a given tube size and main objective size, and base cant?

    Barring that, can someone check my math? I have a 30mm tube with a 50mm main objective. That means that 50-30=20mm sticks out of the scope rings. Dividing that in half gives 10mm between the bottom of the scope ring hole and the barrel. So my rings need to be 10mm high for clearance, right? That number doesn't include the thickness of the base, which will help.

    Just to add a little confusion if I did the previous calculations correct, I'm looking for a 20 MOA canted base, so it no longer runs parallel to the barrel. a 20 MOA is 1/3 of a degree. The tangent of 1/3 a degree is small, but not negligible. Multiplied by 7 inches (the estimated hang-over length of the scope), and then converted to millimeters gives just over 1mm that I need to account for.

    So I need a total of 11mm from the bottom of my ring to the bottom of the hole in the rings?
     
  2. USSR

    USSR Member

    Joined:
    Jul 7, 2005
    Messages:
    8,390
    Location:
    Finger Lakes Region of NY
    numaone,

    It's not quite that easy. Different barrel contours come into play as well. Tell me what scope and rifle you are talking about.

    Don
     
  3. numaone

    numaone Member

    Joined:
    May 25, 2009
    Messages:
    114
    Location:
    North Carolina
    Don,
    Yea, I see what you mean. I am talking about a Remington 700 sps varmint .308. The barrel seems to taper down a bit adding a little bit of clearance, but I was going to save that as a safety margin.

    I am looking at putting a Bushnell Elite 6500 with a 50mm Objective on it. The tube is 30mm.
     
  4. jim147

    jim147 Member

    Joined:
    Jul 11, 2008
    Messages:
    344
    Location:
    Western MO
    I know it takes more time. But the best way is to get the scope and then install it on clay rings. Check the clay and buy the rings. The way barrels contour your eye relief may be just enough different then someone else's to have to move to the next taller or shorter ring height.

    jm
     
  5. cal74

    cal74 Member

    Joined:
    Jan 13, 2009
    Messages:
    242
    Location:
    Eastern, SD
    More than likely your going to need High rings for that set-up
     
  6. jmr40

    jmr40 Member

    Joined:
    May 26, 2007
    Messages:
    9,887
    I agree that high rings are probably needed. Most companies that manufacture mounts have a webpage listing the type of mounts and what size scopes they work with.
     
  7. browningguy

    browningguy Member

    Joined:
    Jul 21, 2004
    Messages:
    4,523
    Location:
    Houston, TX
    Well I can't do math anymore, but 40mm objectives generally get medium height rings, 44-50 mm objectives get high, AR's get high or extra high. Seriously, all the manufacturers make them slightly different heights. Since I try to use Weaver or picatinny bases on everything now I just keep at least one set of each height on the bench and try them until one fits right.

    It sounds like you are on the right track though, it's just too complicated for an old fart.
     
  8. numaone

    numaone Member

    Joined:
    May 25, 2009
    Messages:
    114
    Location:
    North Carolina
    browningguy,
    I was looking for a number for just those reasons, each ring maker's medium/high is different. I think I can get away with a medium ring, but before I drop alot of money (for a set of rings), I want to make sure they will fit. Meanwhile, I don't yet have the scope to try this out.
     
  9. AirForceShooter

    AirForceShooter Member

    Joined:
    Oct 31, 2004
    Messages:
    2,748
    Location:
    Central Florida
    This is why I have baggies of different sets of rings at very different heights.

    AFS
     
  10. DRYHUMOR

    DRYHUMOR Member

    Joined:
    Jul 6, 2008
    Messages:
    1,956
  11. USSR

    USSR Member

    Joined:
    Jul 7, 2005
    Messages:
    8,390
    Location:
    Finger Lakes Region of NY
    You are correct. Some companies call them standard. In any case, you don't need high rings.

    Don
     
  12. DRYHUMOR

    DRYHUMOR Member

    Joined:
    Jul 6, 2008
    Messages:
    1,956
    Measure the outside bell of your scope to be sure. I'm running a 20 MOA on one of mine with a Leupold. I've got about 2-3mm clearance.
     
  13. dakotasin

    dakotasin Member

    Joined:
    Dec 26, 2002
    Messages:
    4,777
    Location:
    Transient
    my 30 mm tubed, 50mm objective scope on a 20moa base on a rem 700 vls sits in low rings...
     
  14. numaone

    numaone Member

    Joined:
    May 25, 2009
    Messages:
    114
    Location:
    North Carolina
    Thanks for the help. What rings and bases are you guys using? I was looking at Warne one-piece 20 MOA base and Burris Xtreme Medium Rings. But I'm open to all suggestions. I know this is the critical point for the rifle so I'm in the 100-200 range for some quality stuff.

    Recommendations?
     
  15. USSR

    USSR Member

    Joined:
    Jul 7, 2005
    Messages:
    8,390
    Location:
    Finger Lakes Region of NY
    I've got Badger Ordnance 20MOA picatinny rails on all my rifles. Various tactical rings (Badger, Leupold, and TPS).

    Don
     
  16. DRYHUMOR

    DRYHUMOR Member

    Joined:
    Jul 6, 2008
    Messages:
    1,956
    Iron Brigade Armory one pc scope mount, and Farrell rails and rings.
     
  17. dullh

    dullh Member

    Joined:
    May 23, 2009
    Messages:
    187
    Location:
    I-26 Exit 44
    Take your rifle and your scope to the gun shop and pick the rings that allow you to mount the scope as low as possible 1) without touching anything on the rifle and 2) clearing all moving parts.

    I have never seem a ring height calculator, seems like that's not something that would be useful but if you go to MidwayUSA's site they have a ring height selection chart that maybe useful to you.
     
Thread Status:
Not open for further replies.

Share This Page