MOA vs. Bullet Drop Compensator

Discussion in 'Long Range Scopes and Other Optics' started by bigsky, Mar 1, 2007.

  1. bigsky

    bigsky Member

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    I have some questions about MOA dials vs. BDC dials. I am new to LRH and I value your opinions about this. I have a Win Model 70 .270 WSM with a Leupold VX 3 4.5x14x40mm. I have my rifle shooting 1/2 MOA. I am using this rifle to hunt mule deer out to about 600/700 yards. I contacted Leupold and spoke with them about there BDC similiar to the one on The Best Of the West. The individual informed me that he really like the BDC, because it took the guessing out of it. I understand that this BDC dial is particular to the information that you have to provide. Would it be better just to stay with MOA dial? Does this give me more flexibilty? My conditions are usually 7000 ft. at 35 degrees however I could possibly hunt somewere that is 4000 ft. and 50 degrees. I am struggling with this and just wanted to get your guys opiniions. Also how do you guys figure your MOA out in the field? I have some data printed off and was just plaining on sticking it in my hunting pack.
    Thanks for all you help!
     
  2. AJ Peacock

    AJ Peacock Well-Known Member

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    I think you've answered your own question. The BDC's will work if you never change your load, barrel or elevation.

    If you are going to dial your turrets anyway, drop charts and MOA dials will work for all locations, bullet combos etc.

    Carrying a drop chart works, or simply tape it to your stock, the inside of a scope cap or just out to 700 yards, memorize it.

    Do a search on Ballistics Software here on the forum.

    Many people here feel the top of the line software is Exbal, it is nice for giving you an idea of a drop chart for your load/bullet combo. Obviously, you need to shoot at distance to verify the charts.

    http://longrangehunting.com/ubbthreads/s...true#Post115562

    Hope this helps, and Welcome to the forum.

    Don
     

  3. Buffalobob

    Buffalobob Writers Guild

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    You can easily run several different altitudes and tempratures for you bullet with a ballistics program and come up with the compensation needed for your BDC.

    Example is that my elk rifle changes about 0.1 inches of drop for every ten degrees fahrenhiet at 1000 yards. Put differently, every ten degrees of temperature causes the gun to shoot one inch high or lower at 1000 yards. In other words for me to miss based upon temperature it would need to be hot enough to fry and egg on a rock or so cold I would have quit and gone home. I believe I would notice that.

    In as far as altitude goes, every thousand feet of altitude changes my drop by 0.2 inches. This is two inches low or high at 1000 yards. A 3000 feet change is necessary in order for me to miss a deer and about 5000 feet change to miss an elk. If I happen to know these numbers for correcting altitude and temperature in advance I can simply take my BDC knob and back it up or down by the amount needed at the ratio of the distance and still make a clean hit every time.

    One of the great lucky thing for us elk hunters is the adiabatic lapse rate. This causes it to get colder the higher you go in altitude which partially (but not wholly)offsets in opposite directions the errors for a BDC (5.5 degrees F per 1000 feet altitude). How very nice. /ubbthreads/images/graemlins/grin.gif Of course you want to pitch your camp down low where it is warm and hunt high where it is cold. /ubbthreads/images/graemlins/grin.gif
    However if you change bullets you will be in for major grief with a BDC. That will be way too much math to be calculating before every shot, even if you are good at math.


    All of that said, it is simpler to just have straight turrets and the correct drop chart for the day taped to your stock or in your shirt pocket.
     
  4. bigsky

    bigsky Member

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    What do most guys perfer using?
     
  5. Buffalobob

    Buffalobob Writers Guild

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    I would guess and say that probably 25-50% of the people on this site have a 300 - 500 yard gun with a reticle BDC that they use for certain hunting situations. These guys will be shooting something like a muzzle loader or maybe a 257 Roberts where you really can't stretch the gun out much more than that.

    There will be a group of people who hunt the same land with the same gun every year and they will simply not need a complicated system and they will have a knob BDC. I would guess maybe 10-20 % would fall into this category. They will probably not shoot much over 600 yards at a hoofed animal.

    I would guess that maybe less than 10% of the members of this site use a BDC knob on a long range travel gun. In other words a dedicated long range rifle that is taken to many differrent places to hunt many different animls

    I would guess maybe 50- 70 % of the people have a straight knob system and get their drops from a chart or PDA and dial up in inches.

    I would guess maybe 5 percent or less of the people use a mildot reticle to get their holds instead of a dial up adjustment.

    Obviosly people have different guns with different scopes for different animals so I suspect a lot of people use and like the BDCs simplicity for certain types of hunting at medium long range- say 400 - 800 yards.

    When you get into the realm of 800 yards to 1500 yards people have such advanced skills that most will use a straight dial up. I am not aware of anyone on this forum useing a calibrated BDC knob at or beyond 1K and making kills with it at least in the two years I have been reading the hunting stories. Long ago I made one and used it and I know what can be done with one.
     
  6. bigsky

    bigsky Member

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    Thanks for all your help on this... It is nice to speak with knowledgeable people when I am preparing to spend some mula$$$$$. /ubbthreads/images/graemlins/grin.gif
     
  7. goodgrouper

    goodgrouper Well-Known Member

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    +1 for MOA dialing off of known bc values inputted into good programs.

    BDC needs one more letter so it could be a four letter word!
     
  8. CAM

    CAM Well-Known Member

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    GG
    you crack me up!!!
    Here is a four letter(kind of 3 plus 1 number) word!!

    NPR2 /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

    Its NOT a BDC you don't adjusts the nobs for changes!!!
    you just have to be able to count by two to use it!!
    NO CLICKIE UNTILL OVER 1200 yards
    or if it makes you fill better only four clicks up or down.

    Even hardhead Lerch pickedup on it!!
    you and UncleB are the only two left!

    Tonge in check, just messing with you and Lerch!!!
    Hope your all ready for SPRING!!!

    CAM
     
  9. blackco

    blackco Well-Known Member

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    AMEN to huntingbigsky. I really like the people on this board and appreciate hearing what they have to say. Thanks everyone.