20 or 30 moa base question

[Phil]

I need 28.3 MOA to reach 1000 yards,am I better off using a 20 or 30 MOA base?????

If I use the 30 MOA base will I still be able to return to a 100 yard zero?????

12-42 Nightforce NSX .125 adjustments.

 

[ridgeway]

20 is plenty. No problem coming back down to 100 with 20 as well.

 

[Milo 2.0]

A 12-42 NXS scope only has 45moa total travel, a 30moa base wont work.

 

[Phil]

Milo,

I was pretty sure that was the case.....


Sometimes I out think these things so I come here to get confirmation.....

 

[Johnboy]

how to find out if it will work.

find total amount of MOA for the scope being used, then cut that in half ( example 45 total= 22.5 moa )

Now add the amount of MOA you think you'll need to serve your purpose. ( example 22.5 plus 30= 52.5 ) well the 30 want work for its to much and will cause you to bottom out the turret. ( hint not good for a scope )

I'm not the best at telling one how things work so I hope this was helpfull

 

[NateHaler]

A 12-42 NXS scope only has 45moa total travel, a 30moa base wont work.

Not necessarily true. In the couple of dozen or so rifles I've installed scopes on in the past decade, not one of them with a flat mount resulted in the scope being at the midpoint of its adjustment range at a 100y zero. All of them required quite a few MOA, as many as ten or twelve, above the theoretical midpoint, to be zeroed at short range.

So, if the OP's setup resulted in him having a 100y zero -- on a flat mount -- of 8 MOA above the midpoint of the adjustment range, then that means he'd be 30.5 MOA from the bottom, and thus a 30 MOA taper would work. However, all of that is theoretical, and I sure as heck would NOT use a 30 MOA taper base on a scope with such little internal adjustment.

Use the 20 MOA taper, and call it done.

Unless you'll not be shooting short range, in which case it won't matter that you wouldn't be able to get a 100y zero. But for most of us, that would be annoying as hell.

Unless your reticle has intermediate aiming points, ala mildots or any of the various rangefinding/holdoff type reticles widely available these days. In which case, you can probably use a flat mount and use a combination of internal adjustment and holdover, like some of us have (successfully, in matches, honest).

See? This is an easy problem to solve! ;D

 

[Old Navy]

A 12-42 NXS scope only has 45moa total travel, a 30moa base wont work.

Not necessarily true. In the couple of dozen or so rifles I've installed scopes on in the past decade, not one of them with a flat mount resulted in the scope being at the midpoint of its adjustment range at a 100y zero. All of them required quite a few MOA, as many as ten or twelve, above the theoretical midpoint, to be zeroed at short range.

So, if the OP's setup resulted in him having a 100y zero -- on a flat mount -- of 8 MOA above the midpoint of the adjustment range, then that means he'd be 30.5 MOA from the bottom, and thus a 30 MOA taper would work. However, all of that is theoretical, and I sure as heck would NOT use a 30 MOA taper base on a scope with such little internal adjustment.

Use the 20 MOA taper, and call it done.

Unless you'll not be shooting short range, in which case it won't matter that you wouldn't be able to get a 100y zero. But for most of us, that would be annoying as hell.

Unless your reticle has intermediate aiming points, ala mildots or any of the various rangefinding/holdoff type reticles widely available these days. In which case, you can probably use a flat mount and use a combination of internal adjustment and holdover, like some of us have (successfully, in matches, honest).

See? This is an easy problem to solve! ;D

+1 Been waiting a long for this post. Later! Frank

 

[CatShooter]

A 12-42 NXS scope only has 45moa total travel, a 30moa base wont work.

Not necessarily true. In the couple of dozen or so rifles I've installed scopes on in the past decade, not one of them with a flat mount resulted in the scope being at the midpoint of its adjustment range at a 100y zero. All of them required quite a few MOA, as many as ten or twelve, above the theoretical midpoint, to be zeroed at short range.

I have also found this to be true.

I shot my rifles at the long end or long range, so I want all the "up" elevation available.

My approach is to use Burris Signature Zee rings on either Pic rails, or Leupold or Warne two piece, cross slot bases.

I first zero at 100, and then run the elevation dial down to the bottom, and count the clicks - say it is 17 moa.

I add 15 moa worth of the plastic inserts, and that will give me a 100 zero that is 2 moa off the bottom, and in the typical scope, I will have 30 to 40 moa of elevation.

It works great.

 

[Phil]

I too don`t think that I`ve ever optically centered a scope and had it at zero @100 yards.

This is the basis for my question.

I`m shooting a 105 amax from a Dasher as a live varmint gun.

I`m using 3000FPS as an average for velocity and am considering either the Barrett 20/30 MOA rings or the Ivy rings.

Either of them are taller than I`d like but I`m not sure if the 20 MOA and my scopes adjustment plus the reticle will be "the ticket"

Scope has .125 moa adj. and is a NP-R1

 

[M-61]

Doesn't really address the OP's question however, I'm a bit confused why a "0 moa mounts" are actually sold. In my last few rifles it has always been (back to the OP question) a choice between 20 or 30 MOA. Even if the vast majority of my shooting is 100-250 yds, it's nice to know there is a lot of "UP" left in the scope, should I find myself in need of it.
Reading the posts I see JOHNBOY says that bottoming out of a turret is not a good thing for the scope. I was unaware of this and wondered if there is a reason the 'last click' would not be ok for the scope. I do mean 'last click' and not trying to twist it past that.

 

[CatShooter]

Doesn't really address the OP's question however, I'm a bit confused why a "0 moa mounts" are actually sold. In my last few rifles it has always been (back to the OP question) a choice between 20 or 30 MOA. Even if the vast majority of my shooting is 100-250 yds, it's nice to know there is a lot of "UP" left in the scope, should I find myself in need of it.
Reading the posts I see JOHNBOY says that bottoming out of a turret is not a good thing for the scope. I was unaware of this and wondered if there is a reason the 'last click' would not be ok for the scope. I do mean 'last click' and not trying to twist it past that.

I set me scope so I use as much of the elevation as possible, and if the elevation turret is one moa off of the bottom, all the better. I paid for the 40 (or whatever) of up, not 20 up and 20 wasted.

 

[M-61]

Doesn't really address the OP's question however, I'm a bit confused why a "0 moa mounts" are actually sold. In my last few rifles it has always been (back to the OP question) a choice between 20 or 30 MOA. Even if the vast majority of my shooting is 100-250 yds, it's nice to know there is a lot of "UP" left in the scope, should I find myself in need of it.
Reading the posts I see JOHNBOY says that bottoming out of a turret is not a good thing for the scope. I was unaware of this and wondered if there is a reason the 'last click' would not be ok for the scope. I do mean 'last click' and not trying to twist it past that.

I set me scope so I use as much of the elevation as possible, and if the elevation turret is one moa off of the bottom, all the better. I paid for the 40 (or whatever) of up, not 20 up and 20 wasted.

I agree 100%..................just that" bottoming of the turret" caught my attention, as I had never heard about it.
The closer I get to minimum elevation cranked into the scope that puts me on at 100 yds the happier I am. Why would the 'last click' not be ok?

 

[timeout]

Doesn't really address the OP's question however, I'm a bit confused why a "0 moa mounts" are actually sold. In my last few rifles it has always been (back to the OP question) a choice between 20 or 30 MOA. Even if the vast majority of my shooting is 100-250 yds, it's nice to know there is a lot of "UP" left in the scope, should I find myself in need of it.
Reading the posts I see JOHNBOY says that bottoming out of a turret is not a good thing for the scope. I was unaware of this and wondered if there is a reason the 'last click' would not be ok for the scope. I do mean 'last click' and not trying to twist it past that.

I set me scope so I use as much of the elevation as possible, and if the elevation turret is one moa off of the bottom, all the better. I paid for the 40 (or whatever) of up, not 20 up and 20 wasted.

I agree 100%..................just that" bottoming of the turret" caught my attention, as I had never heard about it.
The closer I get to minimum elevation cranked into the scope that puts me on at 100 yds the happier I am. Why would the 'last click' not be ok?

Since the post is regarding 20 or 30 MOA mounts this probably doesn't apply, but in Tony Boyer's book he describes a method to optically center a scope when mounting it. The method is a bit time consuming, but Tony believes that the optics are at their optimum when centered. I'm certainly not knowledgeable enough to argue with him about it.

 

[Phil]

I too have been told that scopes "perform" better when run close to optical center..........

Someone with more knowledge than me will have to elaborate on that topic..

 

[gaboon]

If you are going to shoot mid ranges more go with the 20 moa base.

 

[CatShooter]

Doesn't really address the OP's question however, I'm a bit confused why a "0 moa mounts" are actually sold. In my last few rifles it has always been (back to the OP question) a choice between 20 or 30 MOA. Even if the vast majority of my shooting is 100-250 yds, it's nice to know there is a lot of "UP" left in the scope, should I find myself in need of it.
Reading the posts I see JOHNBOY says that bottoming out of a turret is not a good thing for the scope. I was unaware of this and wondered if there is a reason the 'last click' would not be ok for the scope. I do mean 'last click' and not trying to twist it past that.

I set me scope so I use as much of the elevation as possible, and if the elevation turret is one moa off of the bottom, all the better. I paid for the 40 (or whatever) of up, not 20 up and 20 wasted.

I agree 100%..................just that" bottoming of the turret" caught my attention, as I had never heard about it.
The closer I get to minimum elevation cranked into the scope that puts me on at 100 yds the happier I am. Why would the 'last click' not be ok?

You do not what the erector cell to hit the scope body - so the last moa is for mechanical clearance.

There some that believe that scopes "perform" better when the adjustments are centered - of course centered to what is a basic question.

But this is a myth - if you take two quality scopes, and set the elevation on one so the erector cell is 1 moa from the bottom, and the other so it is centered - then put the turret covers back on, and give to a shooter and ask him which is which - there is no one that can tell the difference.