scope height w/ 20 moa and 100 yd zero

Discussion in 'Long Range Scopes and Other Optics' started by pitsnipe, Feb 28, 2012.

  1. pitsnipe

    pitsnipe Active Member

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    OK, Have a question for those with much more experience (long range) than I. Waiting on my new rifle and getting my "ducks in a row" of parts to have ready to put on it. As I MIGHT have to get shorter rings. So here goes. I'm swapping my Leupold 50mm scope (now on my old Winchester with 2 piece Warne bases) to the new gun and have an EGW 20 moa base to put it on. Now, in my simple mind, the higher the scope is from the LOS down the barrel the farther away, if you will, the LOS through the scope will intersect with the LOS of the barrel. Thus allowing the scope a better chance of achieving a 100 yd zero. Like I said in my simple mind of geometry but these two lines will EVENTUALLY intersect. And preferably you would want that to happen beyond 100 yds (my prefered zero). Am I over thinking this whole thing???
    Thanks in advance.
     
  2. SidecarFlip

    SidecarFlip Well-Known Member

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    Depending on the caliber, I'd be considering sighting in at better than 100 yards.... To start with again, depending on caliber....

    So long as the front bell clears the barrel, it matters little how high the rings are. Your cant rail will give you the additional aduustment in elevation, not the rings. I always go for the lowest possible rings that still allow adequate barrel to objective clearance.

    I see the 'shoot through' rings and I'm not impressed, besides my guns don't have iron sights anyway....
     

  3. royinidaho

    royinidaho Writers Guild

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    Ditto what sidecar said.

    Clearance of the end bell is all ya need and,

    Dump the 100 yd zero for at leat a 200 and preferably 300 yd zero.

    Fewer clicks that way. Do the math to ensure not over doing the mid range trajectory for the 300 yd zeor.
     
  4. Greyfox

    Greyfox Well-Known Member

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    I agree with the prior posts, and your comment on overemphasizing the short range dynamics. It won't be a big deal for hunting purposes at those ranges. As long as your base enables you to get to your zero whether 100 or 200 yards. I think other factors are far more important for long range work. Mount the scope as low as you can, centered, with clearance, make sure it's secure and the crosshairs are level with no cant. This should be checked both mechanically with the scope on the rifle, and at the target. Also, be sure that your scope tracks consistently, and you understand what the true click values are for your scope. The farther out you shoot, the more critical these factors will play into your shooting success. IMHO.
     
  5. SidecarFlip

    SidecarFlip Well-Known Member

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    ...Of course we don't know the caliber of the rifle but we have to assume it's better than a .223 (which works at 100 yards IMO), but if you look at comparative ballistics charts for any cartridge of substance, the ballistics will show a marked climb in trajectory (bullet rise) past the 100 yard zero and then the drop (as the velocity degrades and gravity takes over)......

    Much better off at 200 or 300. I realize that most ranges (at least around here), benchmark at 100 yards so it becomes a matter of finding a range or a field where it's plausible to set a target at 200 or 300 and sighting in for zero at that distance.

    As with any object (in this case an optic) that's mounted higher than needed, harmonics and recoil forces come into play. The higher the optic, the more chance for error (why I don't care for the 'shoot through rings'IMO) and to a lesser extent, the handrail mounted optics on an AR. To me, perching a scope way up there is asking for error..... probably why I'm not a fan of that platform in the first place.....

    You want the objective bell as close to (without physical contact) the barrel as possible. Remember, the optic don't move, the erector system inside the optic moves when you dial the elevation up or down or the windage back and forth.....

    The are some variables involved in that aspect as well, one of the variables is how you sight through the optic in relationship to the stock itself and how you position your cheek (cheek weld) to the stock when using the optic but for practical purposes, the closer the better.....

    I keep various height ring sets in the drawer so I can acclimate my preferences to a particular rifle in relationship to how I sight through a scope on a particular rifle...... That's why (at least for me), ordering a set of rings for a rifle is trial and error, like buying a set of shoes without ever trying them on. If they aren't comfortable, you don't wear them. Same applies to rings.

    Everyone is different in the way they hold their firearm and sight through an optic. Just like eye relief and it's relationship to the shooter. Everyone is different. What works for me, may give you a black eye...or worse.:D
     
  6. SidecarFlip

    SidecarFlip Well-Known Member

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    I may be FOS!!! but the way I align my optics to the firearm is I set the firearm (pistol or long rifle) a gun vise (I use a Tipton pistol/rifle unit) and then level the firearm in the Tipton with a bubble level across the rail or upper receiver.

    I just happen to use a machinist level but any graduated bubble level works.

    I loose mount the scope, set the approximate eye relief, place the level on top of the elevation turret or cap and leve the optic in relationship to the firearm. That works for me, may not work for you.....lol

    Then I witness mark the rear ring and the scope body with a paint mark so when I get the eye relief exactly where I want it, I can align the marks and have no scope cant.

    Just how I do it....

    Of course I've secured the rings (proper torque value) and lapped them beforehand....
     
  7. pitsnipe

    pitsnipe Active Member

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    Thank you everyone for the feedback. I kinda thought I was over thinking it. I'll get the scope as low as I can and sight it in from there. The "standard" 100 yd zero hung me up. Just knowing your dope and holding low (Have mill lines to reference anyway) on those short ones works fine as well. Oh, and its a .308 sorry I didnt mention that before.
     
  8. SidecarFlip

    SidecarFlip Well-Known Member

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    Most .308's are only good for a maximum 600 yards give or take. I have one, well, I will have this evening. I have to pick it up, along with a 7-08.

    Too mnay guns, not enough time.....lol