# Thread: M.O.A. scope base...........education requested.

1. ## M.O.A. scope base...........education requested.

Are there rules of thumb for "NON-Zero" M.O.A. scope base. Are there tables for choosing a 15 or 20 or 25 M.O.A. scope base.....???

Is there a mathematical formula or a constant ratio that is used for this determination. Or is it trial and adjust, trial and adjust....???

2. No tables that I know of. You will need to know how much elevation you will need for your longest distance you will shoot at. Then you will need to know how much elevation your scope provides when mounted on your rifle, usually with a zero MOA base. Then you can determine if you need the added elevation provided by a "slanted" MOA base. And you can then determine how much more elevation you will need. Most of the "long range" scopes have substantial elevation in the adjustments. The slanted bases will make you start closer to the "down" end of your elevation adjustment, thus providing more "up" travel in the elevation knob.

3. Thanks.........good explanation.

Originally Posted by gunbugs
No tables that I know of. You will need to know how much elevation you will need for your longest distance you will shoot at. Then you will need to know how much elevation your scope provides when mounted on your rifle, usually with a zero MOA base. Then you can determine if you need the added elevation provided by a "slanted" MOA base. And you can then determine how much more elevation you will need. Most of the "long range" scopes have substantial elevation in the adjustments. The slanted bases will make you start closer to the "down" end of your elevation adjustment, thus providing more "up" travel in the elevation knob.

4. Originally Posted by gunbugs
No tables that I know of. You will need to know how much elevation you will need for your longest distance you will shoot at. Then you will need to know how much elevation your scope provides when mounted on your rifle, usually with a zero MOA base. Then you can determine if you need the added elevation provided by a "slanted" MOA base. And you can then determine how much more elevation you will need. Most of the "long range" scopes have substantial elevation in the adjustments. The slanted bases will make you start closer to the "down" end of your elevation adjustment, thus providing more "up" travel in the elevation knob.
gunbugs is pretty close with his reply.

Be forewarned though, chasing distance, and long range range precision shooting in general is very easy to chase the rabbit down the hole and get addicted! Nothing like 1+ second flight times that allow a guy to come out of his scope, and get back in it in time to see the splash down range.

5. I calculate these things all the time. Give me the info for your velocity, your bullet (I'll look up the g7 BC), your scope/reticle, sight-in distance and how high your scope is above the bore. I have to go install a scope on a 300WSM and when I'm done I'll figure it out for you.

6. So........then the next question is: Is the rotation of the earth a consistent speed.......???? And at what range do shooters start to factor this rotation into bullet flight relative to the target.........???

7. Originally Posted by AGL4now
So........then the next question is: Is the rotation of the earth a consistent speed.......???? And at what range do shooters start to factor this rotation into bullet flight relative to the target.........???

Don't forget moon phases too.

8. Originally Posted by AGL4now
So........then the next question is: Is the rotation of the earth a consistent speed.......???? And at what range do shooters start to factor this rotation into bullet flight relative to the target.........???
Ha, ha, actually it is. At the equator it's 1000+ mph. If you're shooting north to south you might want to hold into the earth's rotation.

9. I understand that the rotation of the earth and "Time in Flight" does factor into long shots. However; I don't know what if any effect the moon has.

Originally Posted by Music Man
Don't forget moon phases too.

10. Originally Posted by AGL4now
I understand that the rotation of the earth and "Time in Flight" does factor into long shots. However; I don't know what if any effect the moon has.
The moon has zero effect on your shots. That gentleman was just pulling your leg a bit. As to the coreolis (sp) effect, you will not notice it, or it will have minimal effect at shots under a mile. Even at that it is most realized at 90degrees from the equator i.e. Straight north or south shots.

You'd be well advised to focus your learning curve on reading the wind and up and downward angles and the effects it has on your dope.

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11. This is NOT something that I give a rats butt about. But in my novel I have three two man teams on "Overwatch" on each side of Turnagain Pass area. Each two man team is on Overwatch for two hours and off for four hours. This is one of the subjects that get discussed by "ACT-3" (each team is named after a local creek, ACT-3 is Alder Creek Team 3). They have to hold both, the old and new Canyon Creek bridges, till....................(To be continued)

Originally Posted by orion94us
..........You'd be well advised to focus your learning curve on reading the wind and up and downward angles and the effects it has on your dope.
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12. Originally Posted by AGL4now
So........then the next question is: Is the rotation of the earth a consistent speed.......???? And at what range do shooters start to factor this rotation into bullet flight relative to the target.........???
If you really want to understand this from a shooters point of view; take a look at this: http://bulletin.accurateshooter.com/...ect-explained/
Then again if you want to learn about it, you can look at it from my point of view and read FM 6-40
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Craig

13. Originally Posted by AGL4now
This is NOT something that I give a rats butt about. But in my novel I have three two man teams on "Overwatch" on each side of Turnagain Pass area. Each two man team is on Overwatch for two hours and off for four hours. This is one of the subjects that get discussed by "ACT-3" (each team is named after a local creek, ACT-3 is Alder Creek Team 3). They have to hold both, the old and new Canyon Creek bridges, till....................(To be continued)
Aaaannd at that I'm out. I apologize for my misconception as I thought you were a shooter wanting to get into long range shooting or trying to learn more so as to make educated decisions on how to set up your rifle or where to focus your training. Hope your novel comes out great have a nice day.

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14. Sorry.....I did not intend to mislead anyone. I do run drills several times a week, (I ran three drills today) on my private range, but I max-out at 300 meters.

Originally Posted by orion94us
Aaaannd at that I'm out. I apologize for my misconception as I thought you were a shooter wanting to get into long range shooting or trying to learn more so as to make educated decisions on how to set up your rifle or where to focus your training. Hope your novel comes out great have a nice day.

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15. Oops, I also must have misunderstood your post. Sorry.
However, I would be interested in your novel. Sounds like a pretty cool idea for a story. I've had several people on this site recommend books to read. All have turned out to be excellent reads.
Chuck.

16. Well, I still have a 25 MOA base on one of my M-70, but I have not really done much work with it. I did have a M-70 in .300 RUM that I had planned to to set-up for long range.

17. Just to be sure that we are all singing off the same sheet of music; according to the NRA, mid range is 300-600 yards, Long range is 800-1000 yards and ELR is beyond 1000 yards. Yes! the target shooting community in the English speaking countries defines range in yards. Meters are used when NATO becomes involved. or-or, if you gotta sound Tacticool!

18. At 69 y/o I am NOT into Tacticool. Side Note: I know a guy named Craig P. that builds quality long shooters........would you be him......???

Originally Posted by Nanook
Meters are used when NATO becomes involved. or-or, if you gotta sound Tacticool!

19. That be me. I turned 69 about 6 years ago.